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1

FATIGUE DESIGN CURVES FOR  

Office of Scientific and Technical Information (OSTI)

FATIGUE DESIGN CURVES FATIGUE DESIGN CURVES FOR 6061-T6 ALUMINUM* G . T . Yahr Engineering Technology Division Oak Ridge National Laboratory Oak Ridge, Tennessee 37831-8051 ABSTRACT A request has been made to the ASME Boiler and Pressure Vessel Committee that 6061-T6 aluminum be approved for use in the construction of Class 1 welded nuclear vessels so it can be used for the pressure vessel of the Advanced Neutron Source research reactor. Fatigue design curves with and without mean stress effects have been proposed. A knock-down factor of two is applied to the design curve for evaluation of welds. The basis of the curves is explained. The fatigue design curves are compared to fatigue data from base metal and weldments. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States

2

Review of the margins for ASME code fatigue design curve - effects of surface roughness and material variability.  

Science Conference Proceedings (OSTI)

The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. The Code specifies fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Existing fatigue strain-vs.-life ({var_epsilon}-N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. This report provides an overview of the existing fatigue {var_epsilon}-N data for carbon and low-alloy steels and wrought and cast austenitic SSs to define the effects of key material, loading, and environmental parameters on the fatigue lives of the steels. Experimental data are presented on the effects of surface roughness on the fatigue life of these steels in air and LWR environments. Statistical models are presented for estimating the fatigue {var_epsilon}-N curves as a function of the material, loading, and environmental parameters. Two methods for incorporating environmental effects into the ASME Code fatigue evaluations are discussed. Data available in the literature have been reviewed to evaluate the conservatism in the existing ASME Code fatigue evaluations. A critical review of the margins for ASME Code fatigue design curves is presented.

Chopra, O. K.; Shack, W. J.; Energy Technology

2003-10-03T23:59:59.000Z

3

Fatigue behavior and recommended design rules for an automotive composite  

DOE Green Energy (OSTI)

Fatigue curves (stress vs cycles to failure) were generated under a variety of conditions (temperatures, fluid environments, mean stresses, block loadings) for a candidate automotive structural composite. The results were used to (1) develop observations regarding basic fatigue behavioral characteristics and (2) establish fatigue design rules. The composite was a structural reaction injection-molded polyurethane reinforced with continuous strand, swirl-mat E-glass fibers. Tensile fatigue tests on specimens from a single plaque at {minus}40 F, room temperature, and 250 F provided the basic behavioral characteristics. It was found that when stress was normalized by the at-temperature ultimate tensile strength, the fatigue curves at the three temperatures collapsed into a single master curve. An assessment of the individual stress-strain loops throughout each test showed a progressive loss in stiffness and an increase in permanent strain, both of which are indicative of increasing damage. Fatigue tests on specimens from several plaques were used to develop a design fatigue curve, which was established by using a reduction factor of 20 on average cycles to failure. This factor assures that the stiffness loss during the design life is no greater than 10 percent. Fatigue reduction factors were established to account for various fluids. Reversed stress fatigue tests allowed a mean stress rule to be validated, and block loading tests were used to demonstrate the adequacy of Miner`s rule for cumulative fatigue damage.

Corum, J.M.; Battiste, R.L.; Ruggles, M.B.

1998-11-01T23:59:59.000Z

4

Dwell Fatigue Design Criteria - Programmaster.org  

Science Conference Proceedings (OSTI)

Energy Based Fatigue Life Prediction Models and Methods for Combined Low Cycle and High Cycle Fatigue · Fatigue Behavior of AM60B Subjected to Variable  ...

5

A curve design method with shape control  

Science Conference Proceedings (OSTI)

A curve design method has been proposed which, in addition to enjoying the good features of cubic splines, possesses interested shape design features too. Two families of shape parameters have been introduced in such a way that one family of parameters ... Keywords: Bernstein-Bézier, interpolation, shape control, spline, tension

M. Sarfraz; M. Balah

2003-05-01T23:59:59.000Z

6

Designing Oceanographic Surface Moorings to Withstand Fatigue  

Science Conference Proceedings (OSTI)

A method is presented for predicting the fatigue resistance of a single-point oceanographic mooring. The method determines the fraction of life that the components of a mooring lose during a deployment by combining results of dynamic analysis, ...

Mark A. Grosenbaugh

1995-10-01T23:59:59.000Z

7

Cyclic fatigue and resistance-curve behavior of an in situ toughened silicon carbide with Al-B-C additions  

Science Conference Proceedings (OSTI)

The room-temperature crack-growth properties of an in situ toughened, monolithic silicon carbide are reported. Hot pressing was performed at 1900 C with 3 wt.% Al, 2 wt.% C and 0.6 wt.% B additions. Compared to a commercial SiC (Hexoloy SA), significant improvements in both the fracture toughness and cyclic fatigue-crack propagation resistance have been achieved through control of the {beta} to {alpha} transformation. Using fatigue-precracked, disk-shaped compact-tension specimens, marked rising resistance-curve behavior was measured over the first {approximately}600 {micro}m of crack extension, leading to a plateau fracture toughness of K{sub c} {approximately} 9.1 MPa{radical}m; this represents more than a threefold increase over the toughness of Hexoloy, where a K{sub c} value of 2.5 MPa{radical}m was measured with no evidence of a resistance curve. Cyclic fatigue-crack growth rates in the toughened SiC were found to be faster than those under sustained loads (static fatigue) at the same stress-intensity level. The cyclic fatigue-crack growth resistance was found to be far superior to that of Hexoloy. Whereas cracking in the commercial SiC became unstable when the maximum stress intensity K{sub max} exceeded {approximately}2 MPa{radical}m, thresholds for fatigue-crack growth in the in situ toughened material exceeded a K{sub max} of 7 MPa{radical}m. Such dramatic improvements in the crack-growth resistance of SiC are attributed to a microstructure consisting of a network of interlocking, plate-like predominantly {alpha}-phase grains, which combine to both bridge and deflect the crack. These results represent the first reported evidence of cyclic fatigue behavior in a monolithic silicon carbide and the first direct measurement of the resistance curve properties in this ceramic.

Gilbert, C.J.; Cao, J.J.; Moberlychan, W.J.; DeJonghe, L.C.; Ritchie, R.O. [Lawrence Berkeley Lab., CA (United States). Materials Science Div.]|[Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

1996-08-01T23:59:59.000Z

8

Available Technologies: Curved Mandrel Design Enabling ...  

A Berkeley Lab team of engineers led by Shlomo Caspi has invented a technology to construct a curved superconducting magnet capable of bending an ion beam 90° in a ...

9

Design criteria and mitigation options for thermal fatigue effects in ATW blankets.  

Science Conference Proceedings (OSTI)

Thermal fatigue due to beam interruptions is an issue that must be addressed in the design of an ATW blanket. Two different approaches can be taken to address this issue. One approach is to analyze current ATW blanket designs in order to set interrupt frequency design limits for the accelerator. The other approach is to assume that accelerator reliability can not be guaranteed before design and construction of the blanket. In this approach the blanket must be designed so as to accommodate an accelerator with a beam interruption frequency significantly higher than current high power accelerators in order to provide a margin of error. Both approaches are considered in this paper. Both a sodium cooled blanket design and a lead-bismuth cooled blanket design are considered. Thermal hydraulic analysis of the blanket for beam interruption transients is carried out with the SASSYS-1 systems analysis code to obtain the time histories of the coolant temperatures in contact with structural components. These coolant temperatures are then used in a detailed structure temperature calculation to obtain structure surface and structure average temperatures. The difference between the average temperature and the surface temperature is used to obtain thermal strains. Low cycle fatigue curves from the American Society of Mechanical Engineers Boiler and Pressure Vessel Code are used to determine the number of cycles that the structural components can endure, based on these strains. Calculations are made for base case designs and for a number of mitigation options. The mitigation options include using two separate accelerators to provide the beam, reducing the thickness of the above core load pads in the subassemblies, increasing the coolant flow rate or reducing power in order to reduce the core temperature rise, and reducing the superheat in the once-through steam generator.

Dunn, F. E.

2000-12-07T23:59:59.000Z

10

Conductor fatigue life research. Final report  

Science Conference Proceedings (OSTI)

Objective of this Phase II work was to experimentally evaluate the long-term effectiveness of amplitude reductions in arresting the aeolian fatigue deterioration of minimally damaged ACSR conductors supported in standard short-radius suspension clamps. The aeolian vibration was simulated by mechanical means in a controlled laboratory situation and the reduction in vibration amplitudes was a simulation of the addition of amplitude limiting devices (dampers). Conductors were vibrated at high amplitudes until a predetermined number of strand breaks occurred, after which the vibration was continued at reduced amplitudes. The Phase II research expanded the number of cycles of vibration and amplitude reduction values for the conductors used in the Phase I effort. The results indicated that the amplitude reductions arrested long-term fatigue strand breaks in every case tested. Additionally, the maximum fatigue damage arrestment amplitude was expanded and evaluated to be 20 mils at the 3-1/2 inch location for Drake ACSR conductor. Electric utilities can utilize the results of this EPRI project in assessing the fatigue life of minimally damaged transmission lines and in evaluating techniques for mitigating fatigue damage. A secondary objective of the Phase II effort was to develop aeolian vibration Load-N curves (dynamic bending stress versus number of cycles of vibration curves) for some ACSR conductors based on Ontario-Hydro recorder and wind data. The wind data generated Load-N curves developed appear to be too conservative. The modified worst-case Ontario-Hydro recorder Load-N curve developed is recommended as a design guideline curve for aeolian fatigue troubled lines in Georgia. The development and use of Load-N curves in conjunction with S-N curves are required for rational aeolian fatigue design of overhead conductors, and for estimating line fatigue lives.

Ramey, G.E.

1983-11-01T23:59:59.000Z

11

Effects of Materials Parameters and Design Details on the Fatigue of Composite Materials for Wind Turbine Blades  

DOE Green Energy (OSTI)

This paper presents an analysis of the results of nine years of fatigue testing represented in the USDOE/Montana State University (DOE/MSU) Composite Materials Fatigue Database. The focus of the program has been to explore a broad range of glass-fiber-based materials parameters encompassing over 4500 data points for 130 materials systems. Significant trends and transitions in fatigue resistance are shown as the fiber content and fabric architecture are varied. The effects of structural details including ply drops, bonded stiffeners, and other geometries that produce local variations in fiber packing and geometry are also described. Fatigue tests on composite beam structures are then discussed; these show generally good correlation with coupon fatigue data in the database. Goodman diagrams for fatigue design are presented, and their application to predicting the service lifetime of blades is described.

Mandell, J.F.; Samborsky, D.D.; Sutherland, H.J.

1999-03-04T23:59:59.000Z

12

An implicit integration procedure for an elasto-viscoplastic model and its application to thermomechanical fatigue design of automotive parts  

Science Conference Proceedings (OSTI)

Thermomechanical fatigue (TMF) design has nowadays become essential for many industrial parts and cyclic elasto-viscoplastic constitutive models and their numerical integration are the crucial point of the problem. The paper first presents an implicit ... Keywords: Constitutive model, FEM analysis, Numerical integration, Return mapping, Thermomechanical fatigue, Viscoplasticity

F. Szmytka; M. H. Maitournam; L. RéMy

2013-04-01T23:59:59.000Z

13

Design computing of complex-curved geometry using digital fabrication methods  

E-Print Network (OSTI)

The production of design information for digital fabrication is presented in this thesis. This thesis outlines the research of generating information for physical construction as architectural models of complex curved walls ...

Griffith, Kenfield A. (Kenfield Allistair)

2006-01-01T23:59:59.000Z

14

Evaluation of weldment creep and fatigue strength-reduction factors for elevated-temperature design  

SciTech Connect

New explicit weldment strength criteria in the form of creep and fatigue strength-reduction factors were recently introduced into the American Society of Mechanical Engineers Code Case N-47, which governs the design of elevated-temperature nuclear plants components in the United States. This paper provides some of the background and logic for these factors and their use, and it describes the results of a series of long-term, confirmatory, creep-rupture and fatigue tests of simple welded structures. The structures (welded plates and tubes) were made of 316 stainless steel base metal and 16-8-2 weld filler metal. Overall, the results provide further substantiation of the validity of the strength-reduction factor approach for ensuring adequate life in elevated-temperature nuclear component weldments. 16 refs., 7 figs.

Corum, J.M.

1989-01-01T23:59:59.000Z

15

The impact of modern headlamps on the design of sag vertical curves  

E-Print Network (OSTI)

Incorporating safety in the design of a highway is one of the foremost duties of a design engineer. Design guidelines provide standards that help engineers include safety in the design of various geometric features. However, design guidelines are not frequently revised and do not accommodate for the frequent changes in vehicle design. One such example is the change in vehicle headlamps. These changes significantly impact the illuminance provided on the road and in turn the design formula. Roadway visibility is critical for nighttime driving. In the absence of roadway lighting, vehicle headlamps illuminate the road ahead of a vehicle. Sag vertical curve design depends on the available headlight sight distance provided by the 1 degree upward diverging headlamp beam. The sag curve design formulas were developed in the early 1940s when sealed beam headlamps were predominant. However, headlamps have changed significantly and modern headlamps project less light above the horizontal axis. In this research, the difference in illuminance provided by sealed beam headlamps and modern headlamps was examined. For the theoretical analysis, three different sag curves were analyzed. On these curves, about 26 percent reduction in illuminance was observed at a distance equal to the stopping sight distance when comparing sealed beam to modern headlamps. A change in the headlamp divergence angle from 1.0 degree to 0.85 degree will provide the required illuminance on the road when using modern headlamps. A field study was performed to validate the theoretical calculations. It was observed that for modern headlamps, a divergence angle less than 1 degree and greater than 0.5 degrees will provide illuminance values comparable to sealed beam headlamps. As a part of this research, a preliminary study, examining the impact of degraded headlamp lenses on the illuminance provided on sag vertical curves was conducted. A significant reduction in illuminance reaching the roadway on sag curves was observed, due to headlamp lens degradation.

Gogula, Madhuri

2005-05-01T23:59:59.000Z

16

High-cycle fatigue behavior of type 316 stainless steel at 593/sup 0/C  

SciTech Connect

The available low- and high-cycle fatigue data on Type 316 stainless steel at 593 to 600/sup 0/C have been combined and analyzed to provide a preliminary strain-life correlation. This correlation was then reduced by the appropriate safety factors to a design curve and compared with the ASME T-1420-1B curve. The comparison indicates that significant increases in allowable fatigue cycles should be realized when the present study is concluded.

Raske, D.T.

1980-01-01T23:59:59.000Z

17

Assessment of Reactivity Margins and Loading Curves for PWR Burnup Credit Cask Designs  

SciTech Connect

This report presents studies to assess reactivity margins and loading curves for pressurized water reactor (PWR) burnup-credit criticality safety evaluations. The studies are based on a generic high-density 32-assembly cask and systematically vary individual calculational (depletion and criticality) assumptions to demonstrate the impact on the predicted effective neutron multiplication factor, k{sub eff}, and burnup-credit loading curves. The purpose of this report is to provide a greater understanding of the importance of input parameter variations and quantify the impact of calculational assumptions on the outcome of a burnup-credit evaluation. This study should provide guidance to regulators and industry on the technical areas where improved information will most enhance the estimation of accurate subcritical margins. Based on these studies, areas where future work may provide the most benefit are identified. The report also includes an evaluation of the degree of burnup credit needed for high-density casks to transport the current spent nuclear fuel inventory. By comparing PWR discharge data to actinide-only based loading curves and determining the number of assemblies that meet the loading criteria, this evaluation finds that additional negative reactivity (through either increased credit for fuel burnup or cask design/utilization modifications) is necessary to accommodate the majority of current spent fuel assemblies in high-capacity casks. Assemblies that are not acceptable for loading in the prototypic high-capacity cask may be stored or transported by other means (e.g., lower capacity casks that utilize flux traps and/or increased fixed poison concentrations or high-capacity casks with design/utilization modifications).

Wagner, J.C.

2002-12-17T23:59:59.000Z

18

Effects of LWR coolant environments on fatigue lives of austenitic stainless steels  

Science Conference Proceedings (OSTI)

The ASME Boiler and Pressure Vessel Code fatigue design curves for structural materials do not explicitly address the effects of reactor coolant environments on fatigue life. Recent test data indicate a significant decrease in fatigue life of pressure vessel and piping materials in light water reactor (LWR) environments. Fatigue tests have been conducted on Types 304 and 316NG stainless steel in air and LWR environments to evaluate the effects of various material and loading variables, e.g., steel type, strain rate, dissolved oxygen (DO) in water, and strain range, on fatigue lives of these steels. The results confirm the significant decrease in fatigue life in water. The environmentally assisted decrease in fatigue life depends both on strain rate and DO content in water. A decrease in strain rate from 0.4 to 0.004%/s decreases fatigue life by a factor of {approx} 8. However, unlike carbon and low-alloy steels, environmental effects are more pronounced in low-DO than in high-DO water. At {approx} 0.004%/s strain rate, reduction in fatigue life in water containing <10 ppb D is greater by a factor of {approx} 2 than in water containing {ge} 200 ppb DO. Experimental results have been compared with estimates of fatigue life based on the statistical model. The formation and growth of fatigue cracks in austenitic stainless steels in air and LWR environments are discussed.

Chopra, O.K.; Gavenda, D.J. [Argonne National Lab., IL (United States). Energy Technology Div.

1997-07-01T23:59:59.000Z

19

Review of elastic stress and fatigue-to-failure data for branch connections and tees in relation to ASME design criteria for nuclear power piping systems  

SciTech Connect

This is the third in a series of reports on the state-of-the art design guidance for piping system branch connections and tees provided by Section III of the ASME Boiler and Pressure Vessel Code. The other reports covered primary or limit-loads and nozzle flexibility. The principal objective of this report, as with the others, was to identify and collect the pertinent literature on the the subject and to identify needed improvements in the design methods and criteria of the Code based on the evaluation of the available information. This report does not propose changes in the design procedure of the Code. This report discusses the evaluation of stresses in branch connections and tees, correlation of these stresses with fatigue failures, and the Code rules for protection against fatigue failure in design applications. Because of the extensive amount of available information, the report was divided into two parts. Part I discusses cyclic internal pressure loading and Part II discusses moment loadings for the branch and run. The cyclic pressure loading fatigue parameters are mostly based on leakage, whereas, if the parameters were based on crack initiation, different and possibly higher valves would be developed. The fatigue evaluation procedure, which attempts to relate fatigue strength of piping components to strain-controlled, polished bar, and fatigue data appears to be inaccurate on the conservative side for high amplitude cycles and inaccurate on the unconservative side for low amplitude cycles. The report proposes additional analytical and experimental work.

Rodabaugh, E.C.; Moore, S.E.; Gwaltney, R.C.

1994-05-01T23:59:59.000Z

20

On the Design and Optimization of a Quantum Polynomial-Time Attack on Elliptic Curve Cryptography  

Science Conference Proceedings (OSTI)

We consider a quantum polynomial-time algorithm which solves the discrete logarithm problem for points on elliptic curves over GF (2 m ). We improve over earlier algorithms by constructing an efficient ...

Donny Cheung; Dmitri Maslov; Jimson Mathew; Dhiraj K. Pradhan

2008-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

The Development of Confidence Limits for Fatigue Strength Data  

DOE Green Energy (OSTI)

Over the past several years, extensive databases have been developed for the S-N behavior of various materials used in wind turbine blades, primarily fiberglass composites. These data are typically presented both in their raw form and curve fit to define their average properties. For design, confidence limits must be placed on these descriptions. In particular, most designs call for the 95/95 design values; namely, with a 95% level of confidence, the designer is assured that 95% of the material will meet or exceed the design value. For such material properties as the ultimate strength, the procedures for estimating its value at a particular confidence level is well defined if the measured values follow a normal or a log-normal distribution. Namely, based upon the number of sample points and their standard deviation, a commonly-found table may be used to determine the survival percentage at a particular confidence level with respect to its mean value. The same is true for fatigue data at a constant stress level (the number of cycles to failure N at stress level S{sub 1}). However, when the stress level is allowed to vary, as with a typical S-N fatigue curve, the procedures for determining confidence limits are not as well defined. This paper outlines techniques for determining confidence limits of fatigue data. Different approaches to estimating the 95/95 level are compared. Data from the MSU/DOE and the FACT fatigue databases are used to illustrate typical results.

SUTHERLAND,HERBERT J.; VEERS,PAUL S.

1999-11-09T23:59:59.000Z

22

An Energy Based Fatigue Life Prediction Framework for In-Service Structural Components  

Science Conference Proceedings (OSTI)

An energy based fatigue life prediction framework has been developed for calculation of remaining fatigue life of in service gas turbine materials. The purpose of the life prediction framework is to account aging effect caused by cyclic loadings on fatigue strength of gas turbine engines structural components which are usually designed for very long life. Previous studies indicate the total strain energy dissipated during a monotonic fracture process and a cyclic process is a material property that can be determined by measuring the area underneath the monotonic true stress-strain curve and the sum of the area within each hysteresis loop in the cyclic process, respectively. The energy-based fatigue life prediction framework consists of the following entities: (1) development of a testing procedure to achieve plastic energy dissipation per life cycle and (2) incorporation of an energy-based fatigue life calculation scheme to determine the remaining fatigue life of in-service gas turbine materials. The accuracy of the remaining fatigue life prediction method was verified by comparison between model approximation and experimental results of Aluminum 6061-T6. The comparison shows promising agreement, thus validating the capability of the framework to produce accurate fatigue life prediction.

H. Ozaltun; M. H.H. Shen; T. George; C. Cross

2011-06-01T23:59:59.000Z

23

Projection of fractures in ships for the evaluation of fatigue resistant designs  

E-Print Network (OSTI)

Cracks in ships have been of great concern to the maritime industry for a very long time. The problem is controlled by improving design, minimizing operating stresses and through regular inspections and repairs. The big ...

Hadjiyiannis, Nicholas

2009-01-01T23:59:59.000Z

24

Design, build and test of an axial flow hydrokinetic turbine with fatigue analysis  

E-Print Network (OSTI)

OpenProp is an open source propeller and turbine design and analysis code that has been in development since 2007 by MIT graduate students under the supervision of Professor Richard Kimball. In order to test the performance ...

Ketcham, Jerod W

2010-01-01T23:59:59.000Z

25

High Cycle Fatigue of ULTIMET Alloy  

Science Conference Proceedings (OSTI)

curves of this alloy regardless of the testing frequencies and environments. At 20 Hz ... The availability of fatigue data in ULTIMET alloy will provide new commercial .... perchloric, 90 ml distilled water, and 100 ml butylcellosolve was used for ...

26

Development of Yield and Tensile Strength Design Curves for Alloy 617  

SciTech Connect

The U.S. Department of Energy Very High Temperature Reactor Program is acquiring data in preparation for developing an Alloy 617 Code Case for inclusion in the nuclear section of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code. A draft code case was previously developed, but effort was suspended before acceptance by ASME. As part of the draft code case effort, a database was compiled of yield and tensile strength data from tests performed in air. Yield strength and tensile strength at temperature are used to set time independent allowable stress for construction materials in B&PV Code, Section III, Subsection NH. The yield and tensile strength data used for the draft code case has been augmented with additional data generated by Idaho National Laboratory and Oak Ridge National Laboratory in the U.S. and CEA in France. The standard ASME Section II procedure for generating yield and tensile strength at temperature is presented, along with alternate methods that accommodate the change in temperature trends seen at high temperatures, resulting in a more consistent design margin over the temperature range of interest.

Nancy Lybeck; T. -L. Sham

2013-10-01T23:59:59.000Z

27

Thermal fatigue due to beam interruptions in a Lead-Bismuth cooled ATW blanket  

Science Conference Proceedings (OSTI)

Thermal fatigue consequences of frequent accelerator beam interruptions are quantified for both sodium and lead-bismuth cooled blankets in current designs for accelerator transmutation of waste devices. Temperature response was calculated using the SASSYS-1 systems analysis code for an immediate drop in beam current from full power to zero. Coolant temperatures from SASSYS-1 were fed into a multi-node structure temperature calculation to obtain thermal strains for various structural components. Fatigue curves from the American Society of Mechanical Engineers Boiler and Pressure Vessel Code were used to determine the number of cycles that these components could endure, based on these thermal strains. Beam interruption frequency data from a current accelerator were used to estimate design lifetimes for components. Mitigation options for reducing thermal fatigue are discussed.

Dunn, F.

2000-11-15T23:59:59.000Z

28

Crystallographic Orientation Dependence of Fatigue Crack ...  

Science Conference Proceedings (OSTI)

In the present study, fatigue crack propagation behavior of rolled AZ31B magnesium ... Alloy Design for Enhancing the Fracture Resistance of Heat Treated High ...

29

Pressure vessel and piping codes. Technical basis for revised reference crack growth rate curves for pressure boundary steels in LWR environment  

SciTech Connect

Since the inception of the pressure vessel and piping codes the reference fatigue crack growth rate curves have been contained in Appendix A of Sect. XI. The curves have been designed to be applicable to carbon and low alloy pressure vessel steels exposed to either air or light water reactor coolant environments. Data obtained over the past several years have shown a different behavior of these steels in the light water reactor environment than that predicted by the present reference curve. A revised set of reference curves has been formulated, incorporating a new curve shape as well as a dependency of growth rate on R ratio (minimum load/maximum load). This work provides the background and justification for such a revision, details the methodology used to develop the revised curves, and includes an evalution of the adequacy and impact of the revised curves as compared with the single curve which they replace. 24 references.

Bamford, W.H.

1980-11-01T23:59:59.000Z

30

Comparisons of Wilson-Fowler and Parametric Cubic Splines with the Curve-Fitting Algorithms of Several Computer-Aided Design Systems  

SciTech Connect

The purpose of this report is to demonstrate that modern computer-aided design (CAD), computer-aided manufacturing (CAM), and computer-aided engineering (CAE) systems can be used in the Department of Energy (DOE) Nuclear Weapons Complex (NWC) to design new and remodel old products, fabricate old and new parts, and reproduce legacy data within the inspection uncertainty limits. In this study, two two-dimensional splines are compared with several modern CAD curve-fitting modeling algorithms. The first curve-fitting algorithm is called the Wilson-Fowler Spline (WFS), and the second is called a parametric cubic spline (PCS). Modern CAD systems usually utilize either parametric cubic and/or B-splines.

Birchler, W.D.; Schilling, S.A.

2001-02-01T23:59:59.000Z

31

Aircraft Corrosion Fatigue Assessment  

Science Conference Proceedings (OSTI)

...Fatigue in the Presence of Corrosion, Proc., NATO Research and Technology Organization Meeting (Corfu,

32

High cycle fatigue and fatigue crack propagation behavior of ...  

Science Conference Proceedings (OSTI)

And fatigue crack propagation rates of modified A7075 showed slightly lower. Those superior fatigue strength and resistance of fatigue crack propagation of ...

33

Fatigue and Fatigue Crack Propagation Behaviors of High ...  

Science Conference Proceedings (OSTI)

The S-N fatigue and fatigue crack propagation (FCP) behaviors of high ... The mechanisms associated with the improved fatigue resistance for the high ...

34

Design and development of a high-concentration and high-efficiency photovoltaic concentrator using a curved Fresnel lens  

DOE Green Energy (OSTI)

Thermo Electron has designed a high concentration photovoltaic module that uses a domed, point-focus Fresnel lens. Their design, design optimization process, and results from lens and receiver tests are described in this report. A complete module has not been fabricated and probably will not be fabricated in the future; however, Thermo Electron's optical design, analysis, and testing of both secondary optical units and domed Fresnel lenses have made a significant contribution to our project. Tooling errors prevented the lens from reaching its potential efficiency by the end of the contract, and resolution of these tooling problems is currently being attempted with a follow-on contract, No. 68-9463.

Scharlack, R.S.; Moffat, A.

1983-08-01T23:59:59.000Z

35

Estimates of thermal fatigue due to beam interruptions for an ALMR-type ATW  

SciTech Connect

Thermal fatigue due to beam interruptions has been investigated in a sodium cooled ATW using the Advanced Liquid Metal mod B design as a basis for the subcritical source driven reactor. A k{sub eff} of 0.975 was used for the reactor. Temperature response in the primary coolant system was calculated, using the SASSYS- 1 code, for a drop in beam current from full power to zero in 1 microsecond.. Temperature differences were used to calculate thermal stresses. Fatigue curves from the American Society of Mechanical Engineers Boiler and Pressure Vessel Code were used to determine the number of cycles various components should be designed for, based on these thermal stresses.

Dunn, F. E.; Wade, D. C.

1999-11-12T23:59:59.000Z

36

On the Fatigue Analysis of Wind Turbines  

DOE Green Energy (OSTI)

Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. Operational experiences with these large rotating machines indicated that their components (primarily blades and blade joints) were failing at unexpectedly high rates, which led the wind turbine community to develop fatigue analysis capabilities for wind turbines. Our ability to analyze the fatigue behavior of wind turbine components has matured to the point that the prediction of service lifetime is becoming an essential part of the design process. In this review paper, I summarize the technology and describe the ''best practices'' for the fatigue analysis of a wind turbine component. The paper focuses on U.S. technology, but cites European references that provide important insights into the fatigue analysis of wind turbines.

Sutherland, Herbert J.

1999-06-01T23:59:59.000Z

37

Fatigue of Nanocrystalline Materials and Fatigue Property ...  

Science Conference Proceedings (OSTI)

Mar 1, 2011 ... Effects of Ultrasonic Nanocrystal Surface Modification on Fatigue Behavior of SUS316 Austenitic Stainless Steel Tube for Stents: Auezhan ...

38

Probabilistic fatigue methodology and wind turbine reliability  

DOE Green Energy (OSTI)

Wind turbines subjected to highly irregular loadings due to wind, gravity, and gyroscopic effects are especially vulnerable to fatigue damage. The objective of this study is to develop and illustrate methods for the probabilistic analysis and design of fatigue-sensitive wind turbine components. A computer program (CYCLES) that estimates fatigue reliability of structural and mechanical components has been developed. A FORM/SORM analysis is used to compute failure probabilities and importance factors of the random variables. The limit state equation includes uncertainty in environmental loading, gross structural response, and local fatigue properties. Several techniques are shown to better study fatigue loads data. Common one-parameter models, such as the Rayleigh and exponential models are shown to produce dramatically different estimates of load distributions and fatigue damage. Improved fits may be achieved with the two-parameter Weibull model. High b values require better modeling of relatively large stress ranges; this is effectively done by matching at least two moments (Weibull) and better by matching still higher moments. For this purpose, a new, four-moment {open_quotes}generalized Weibull{close_quotes} model is introduced. Load and resistance factor design (LRFD) methodology for design against fatigue is proposed and demonstrated using data from two horizontal-axis wind turbines. To estimate fatigue damage, wind turbine blade loads have been represented by their first three statistical moments across a range of wind conditions. Based on the moments {mu}{sub 1}{hor_ellipsis}{mu}{sub 3}, new {open_quotes}quadratic Weibull{close_quotes} load distribution models are introduced. The fatigue reliability is found to be notably affected by the choice of load distribution model.

Lange, C.H. [Stanford Univ., CA (United States)

1996-05-01T23:59:59.000Z

39

Optimal Railroad Rail Grinding for Fatigue Mitigation  

E-Print Network (OSTI)

This dissertation aims to study the benefit of rail grinding on service life of railroad rails, focusing on failures due to rolling contact fatigue (RCF) at the rail head. Assuming a tangent rail with one-point contact at the running surface, a finite element analysis of a full-scale wheel-rail rolling contact with a nonlinear isotropic kinematic hardening material model is performed to simulate the accumulation of residual stresses and strains in the rail head. Using rolling stress and strain results from the sixth loading cycle, in which residual stresses and strains are at their steady-state, as input, two critical plane fatigue criteria are proposed for fatigue analyses. The first fatigue criterion is the stress-based approach—namely the Findley fatigue criterion. It suggests an important role of tensile residual stresses on subsurface crack nucleation and early growth in the rail head, but applications of the criterion to the near-running-surface region are limited because of plastic deformation from wheel-rail contact. The second fatigue criterion is the strain-based approach—namely the Fatemi-Socie fatigue criterion. Contributed mainly from shear strain amplitudes and factorized by normal stress components, the criterion also predicts fatigue crack nucleation at the subsurface as a possible failure mode as well as fatigue crack nucleation at the near-surface, while maintaining its validity in both regions. A collection of fatigue test data of various types of rail steel from literature is analyzed to determine a relationship between fatigue damages and number of cycles to failure. Considering a set of wheel loads with their corresponding number of rolling passage as a loading unit (LU), optimizations of grinding schedules with genetic algorithm (GA) show that fatigue life of rail increases by varying amount when compared against that from the no-grinding case. Results show that the proposed grinding schedules, optimized with the exploratory and local-search genetic algorithms, can increase fatigue life of rail by 240 percent. The optimization framework is designed to be able to determine a set of optimal grinding schedules for different types of rail steel and different contact configurations, i.e. two-point contact occurred when cornering.

Tangtragulwong, Potchara

2010-12-01T23:59:59.000Z

40

An experimental evaluation of S-N curves and validity of miner's cumulative damage hypothesis for an ACSR conductor  

Science Conference Proceedings (OSTI)

Laboratory simulation of aeolian vibrations was used in determining the fatigue characteristics of an ACSR conductor subjected to constant and varied amplitude loadings. Using linear regression analyses, S-N curves for first through fifth strand breaks were fit to the data, and a pseudo endurance limit of 21.31 MPa (3.09 ksi) estimated. Subjecting the conductor to three different types of load sequences revealed that Miner's Cumulative Damage hypothesis is somewhat conservative, but can be assumed valid for design purposes. This information, in conjunction with the actual load histories, will allow electric utility companies to more accurately design transmission lines.

Brunair, R.M.; Ramey, G. (Auburn Univ., Auburn, AL (US)); Duncan, R.R. III (Univ. of Texas, Austin, TX (US))

1988-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Materials Reliability Program (MRP-149, Revision 1) Fatigue Licensing Basis Monitoring Guideline  

Science Conference Proceedings (OSTI)

All nuclear plants are required to operate their mechanical systems within the parameters defined by fatigue design basis requirements, analyses and assumptions. This monitoring guideline is part of the Electric Power Research Institute’s (EPRI’s) comprehensive and integrated Fatigue Management approach designed to prevent and/or manage cracking of components due to fatigue.BackgroundThis document provides guidance for utility engineers to implement a fatigue ...

2013-12-23T23:59:59.000Z

42

Structural fatigue assessment and management of large-scale port logistics equipments  

Science Conference Proceedings (OSTI)

With the advances of port enterprises, much intensive research has been gradually involved in the structural fatigue assessment and management of port logistics equipments. However, relevant work on large-scale port logistics equipments is still ... Keywords: S-N curve, crack formation, crack propagation life, fatigue assessment, fracture mechanics, gantry cranes, large-scale port logistics equipment, structural safety assessment

Yuan Liu; Weijian Mi; Huiqiang Zheng

2008-11-01T23:59:59.000Z

43

Fatigue Life Data  

Science Conference Proceedings (OSTI)

...It has long been recognized that fatigue data, when resolved into elastic and plastic terms, can be represented as linear functions of life on a logarithmic scale. Figure 41 schematically shows this representation of elastic and plastic components, which together define the total fatigue life...

44

Curves and The Photon  

E-Print Network (OSTI)

The study of the number of photons leads to a new way of characterizing curves and to a novel integral invariant over curves.

L. Stodolsky

2005-11-28T23:59:59.000Z

45

Stress-Based Fatigue Monitoring  

Science Conference Proceedings (OSTI)

The FatiguePro software, developed by the Electric Power Research Institute (EPRI) and first deployed in 1989, is a fatigue monitoring program that is widely used around the world to assist with aging management of nuclear power plants. The FatiguePro stress-based fatigue (SBF) module has used a single stress term for calculating fatigue usage factors. This simplified approach was chosen not only because of computer limitations at the time, but also because the conventional stress cycle counting algorith...

2011-12-05T23:59:59.000Z

46

Fatigue Property Enhancement and Life Prediction  

Science Conference Proceedings (OSTI)

Mar 6, 2013 ... Fatigue in Materials: Microstructure-Driven Modeling and In-Situ Fatigue Characterization: Fatigue Property Enhancement and Life Prediction

47

Fatigue Resistance of Carbon Nanotube Reinforced Aluminum ...  

Science Conference Proceedings (OSTI)

Presentation Title, Fatigue Resistance of Carbon Nanotube Reinforced Aluminum ... Fatigue crack propagation (FCP) and fracture mechanism of Al-CNT  ...

48

Digital Jordan curve theorems  

E-Print Network (OSTI)

Abstract. Efim Khalimsky’s digital Jordan curve theorem states that the complement of a Jordan curve in the digital plane equipped with the Khalimsky topology has exactly two connectivity components. We present a new, short proof of this theorem using induction on the Euclidean length of the curve. We also prove that the theorem holds with another topology on the digital plane but then only for a restricted class of Jordan curves. 1

Christer O. Kiselman

2000-01-01T23:59:59.000Z

49

Functional neuroimaging of circadian fatigue  

Science Conference Proceedings (OSTI)

Along with the increase of demanding mental effort work, sleep loss, extended work period, mental fatigue is a very common phenomenon in everyday modern life. Recently, mental fatigue has been receiving increasing attention from military, transport, ...

Xiaoping Li; Bui Ha Duc

2012-12-01T23:59:59.000Z

50

Fatigue case study and reliability analyses for wind turbines  

DOE Green Energy (OSTI)

Modern wind turbines are fatigue critical machines used to produce electrical power. To insure long term, reliable operation, their structure must be optimized if they are to be economically viable. The fatigue and reliability projects in Sandia`s Wind Energy Program are developing the analysis tools required to accomplish these design requirements. The first section of the paper formulates the fatigue analysis of a wind turbine using a cumulative damage technique. The second section uses reliability analysis for quantifying the uncertainties and the inherent randomness associated with turbine performance and the prediction of service lifetimes. Both research areas are highlighted with typical results.

Sutherland, H.J.; Veers, P.S.

1994-12-31T23:59:59.000Z

51

Guidelines for Addressing Environmental Effects in Fatigue Usage Calculations  

Science Conference Proceedings (OSTI)

Requirements by the U.S. Nuclear Regulatory Commission (NRC) to address reactor water environmental effects on fatigue of class 1 reactor pressure boundary components in license renewal evaluations and for new plants have led to the development of American Society of Mechanical Engineers (ASME) Code Cases designed to provide rules for such evaluations. This report describes the results of efforts by industry participants to complete two sample fatigue evaluations according to the rules of ASME Code ...

2012-12-21T23:59:59.000Z

52

Putting a price on worker fatigue  

Science Conference Proceedings (OSTI)

In a round-the-clock industry such as mining, extended work hours may be necessary for production but damaging to the bottom line. A recent report commissioned by the Minerals Council of Australia (MCA) attempts to document the relationship between sleep, working arrangements and fatigue. The study, titled Work Design, Fatigue and Sleep by Dr. Angela Baker and Dr. Sally Ferguson of the Australian Center for Sleep Research at the University of South Australia contains information useful for managing fatigue in the workplace. The publication is available free online at http://www.minerals.org.au. The study offers guidelines for planing work schedules or for chaning shifts. William G. Sirosis, senior vice president and COO of Circadian Technologies Inc., also addressed this topic in a presentation at the recent MineWest 2006 conference. He pointed out that the exact dollar costs of operating with a fatigued workforce was difficult to pinpoint but the cumulative effect can be damaging to a company's production and profitability. He suggested steps to a successful management programme.

Carter, R.A.

2007-03-15T23:59:59.000Z

53

Photovoltaic I-V curve measurement techniques  

SciTech Connect

Performance evaluation of photovoltaic (PV) arrays under actual field conditions provides important feedback to the module design process. One of the principal methods for assessing an array's performance is to plot its current, I, versus voltage, V, curve. Following a brief review of techniques for measuring the I-V curve, a new, capacitive-based approach is presented. It uses a rapid sweep of the I-V curve that substantially reduces the average power transfer between array and load, and in turn, substantially reduces the size and weight of the curve tracer. Both theoretical and practical aspects of the approach are presented for a 10-kW unit. Performance is verified by comparison with I-V curves obtained by using a conventional load. The agreement is found to be excellent. Approximately an order of magnitude reduction in size, weight and power consumption over conventional units was realized with the experimental I-V curve tracer.

Cox, C.H.; Warner, T.H.

1982-08-01T23:59:59.000Z

54

Program 87: Proceedings of the EPRI International Creep-Fatigue Experts Workshop 5: ASTM ;EPRI Creep-Fatigue Interaction Symposium  

Science Conference Proceedings (OSTI)

The industrial need for extended service life of power generation plants calls for assessing the creep-fatigue performance of traditional boiler and turbine components. This is particularly important for structural integrity and safe operation of units designed for base load operation. The Electric Power Research Institute (EPRI) leads an international experts group, including key industry experts and researchers, for Experts Workshop on Creep-Fatigue Damage Interaction, which is held annually.

2011-09-30T23:59:59.000Z

55

Galilean Classification of Curves  

E-Print Network (OSTI)

In this paper, we classify space-time curves up to Galilean group of transformations with Cartan's method of equivalence. As an aim, we elicit invariats from action of special Galilean group on space-time curves, that are, in fact, conservation laws in physics. We also state a necessary and sufficient condition for equivalent Galilean motions.

Mehdi Nadjafikhah; Ali Mahdipour Shirayeh

2007-11-13T23:59:59.000Z

56

A Summary of the Fatigue Properties of Wind Turbine Materials  

DOE Green Energy (OSTI)

Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. The materials used to construct these machines are subjected to a unique loading spectrum that contains several orders of magnitude more cycles than other fatigue critical structures, e.g., an airplane. To facilitate fatigue designs, a large database of material properties has been generated over the past several years that is specialized to materials typically used in wind turbines. In this paper, I review these fatigue data. Major sections are devoted to the properties developed for wood, metals (primarily aluminum) and fiberglass. Special emphasis is placed on the fiberglass discussion because this material is current the material of choice for wind turbine blades. The paper focuses on the data developed in the U.S., but cites European references that provide important insights.

SUTHERLAND, HERBERT J.

1999-10-07T23:59:59.000Z

57

Gaussian Curve Summations  

NLE Websites -- All DOE Office Websites (Extended Search)

Gaussian Curve Summations Gaussian Curve Summations Name: Jay Status: educator Grade: 9-12 Location: MA Country: USA Date: April 2011 Question: I have noticed that when similar Gaussian curves are placed next to each other with 50% overlap between the curves, the summed curves give a constant value equal to the curve peak. Is there a name for this phenomenon, and is it useful in science? Replies: You have to be careful that what appears to be a real mathematical result is analytically true and not a consequence of the scale of the graphing. For example, let us look at two Gaussian curves, G1 = (1/2pi)^1/2 x exp(-1/2(x-1)^2) and G2 = (1/2pi)^1/2 x exp(-1/2(x+1)^2) and their weighted sum Gt(x)= 2 x G1 + 2 x G2. These are two Gaussian curves with mean values (+/-) 1 and standard deviation = 1. That is, they are equally "fat". If you graph Gt(x) between (+/-)0.5, G(t) appears to be a constant very close to unity. However, if you increase the values of 'x' to (+/-)2 you see that the values of Gt = (+/-)0.5. Certainly not a constant. It is a flaw in our scaling of Gt. Or put another way, we are pulling G1 and G2 apart, with no change in the standard deviation. You could make this trickier if you do not hold the standard deviation constant, but make the standard deviation proportional to the mean, so that the curves get "fatter" as you move G1 and G2 apart.

58

Microstructure-Property-Fatigue Deformation & Damage Relationships  

Science Conference Proceedings (OSTI)

Mar 5, 2013 ... Combining DIC and Ultrasonic Fatigue to Investigate the Very High Cycle Fatigue Behavior of Ti-6242: Jason Geathers1; J. Wayne Jones1; ...

59

Ultrasonic Fatigue Testing System Combined with Nondestructive ...  

Science Conference Proceedings (OSTI)

Presentation Title, Ultrasonic Fatigue Testing System Combined with ... High and Very High Cycle Fatigue in Al and Cu Thin Films on Si Substrate.

60

Ultrasonic Fatigue of Advanced Materials and Systems  

Science Conference Proceedings (OSTI)

Combining Ultrasonic Fatigue with Synchrotron X-radiograhy and in situ Nonlinear ... High and Very High Cycle Fatigue in Al and Cu Thin Films on Si Substrate.

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Fatigue and Corrosion Interaction and Materials Corrosion  

Science Conference Proceedings (OSTI)

Mar 1, 2011 ... Fatigue and Corrosion Damage in Metallic Materials: Fundamentals, ... the high stress ratio corrosion fatigue crack threshold and increases the ...

62

Crude oil supply curves  

E-Print Network (OSTI)

Short-run cost curves shift over time as depletion counters increasing knowledge. Under competition, a rightward (leftward) shift indicates lower (higher) cost and greater (lesser) productivity. A simple coefficient captures ...

Adelman, Morris Albert

1998-01-01T23:59:59.000Z

63

Effects of light water reactor coolant environment on the fatigue lives of  

NLE Websites -- All DOE Office Websites (Extended Search)

Effects of light water reactor coolant environment on the fatigue lives of Effects of light water reactor coolant environment on the fatigue lives of reactor materials July 8, 2013 A metal component can become progressively degraded, and its structural integrity can be adversely impacted when it is subjected to repeated fluctuating loads, or fatigue loading. Fatigue loadings on nuclear reactor pressure vessel components can occur because of changes in pressure and temperature caused by transients during operation, such as reactor startup or shutdown and turbine trip events. The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code recognizes fatigue as a possible cause of failure of reactor materials and provides rules for designing nuclear power plant components to avoid fatigue failures. For various materials, the ASME Code defines the

64

Investigation of learning and experience curves  

DOE Green Energy (OSTI)

The applicability of learning and experience curves for predicting future costs of solar technologies is assessed, and the major test case is the production economics of heliostats. Alternative methods for estimating cost reductions in systems manufacture are discussed, and procedures for using learning and experience curves to predict costs are outlined. Because adequate production data often do not exist, production histories of analogous products/processes are analyzed and learning and aggregated cost curves for these surrogates estimated. If the surrogate learning curves apply, they can be used to estimate solar technology costs. The steps involved in generating these cost estimates are given. Second-generation glass-steel and inflated-bubble heliostat design concepts, developed by MDAC and GE, respectively, are described; a costing scenario for 25,000 units/yr is detailed; surrogates for cost analysis are chosen; learning and aggregate cost curves are estimated; and aggregate cost curves for the GE and MDAC designs are estimated. However, an approach that combines a neoclassical production function with a learning-by-doing hypothesis is needed to yield a cost relation compatible with the historical learning curve and the traditional cost function of economic theory.

Krawiec, F.; Thornton, J.; Edesess, M.

1980-04-01T23:59:59.000Z

65

Characterization of Fatigue Crack Propagation in a Haynes 230 ...  

Science Conference Proceedings (OSTI)

Energy Based Fatigue Life Prediction Models and Methods for Combined Low Cycle and High Cycle Fatigue · Fatigue Behavior of AM60B Subjected to Variable  ...

66

The High Cycle Fatigue, Damage Initiation and Growth and Final ...  

Science Conference Proceedings (OSTI)

Energy Based Fatigue Life Prediction Models and Methods for Combined Low Cycle and High Cycle Fatigue · Fatigue Behavior of AM60B Subjected to Variable  ...

67

Fatigue Crack Initiation in Nickel-Based Superalloy René 88 DT at ...  

Science Conference Proceedings (OSTI)

9% distilled water and 13% butyl cellosolve under conditions of. -35°C, 20V and ... The ultrasonic fatigue stress-life curve for René 88 DT at 593?C is shown in Figure 4 ... 600MPa. Figure 4. S-N data of Rene 88 DT at 593?C (Arrows indicate.

68

Evaluation of Thermal-, Creep-, and Corrosion-Fatigue of Heat Recovery Steam Generator Pressure Parts  

Science Conference Proceedings (OSTI)

The worldwide fleet of combined cycle units with heat recovery steam generators (HRSG) has exhibited a disappointing track record with respect to reliability and availability in terms of fatigue HRSG tube failures (HTF) which are thermal transient driven. This report, which forms part of a series, will assist designer, owners, and operators with the technical basis to facilitate specifying, designing, and operating HRSG in a manner to minimize fatigue damage.

2006-03-31T23:59:59.000Z

69

Fatigue Weak-Link Density and Strength Distribution in High ...  

Science Conference Proceedings (OSTI)

Symposium, Fatigue and Corrosion Damage in Metallic Materials: Fundamentals, Modeling and Prevention. Presentation Title, Fatigue Weak-Link Density and ...

70

Transfinite partitions of Jordan curves  

E-Print Network (OSTI)

The w-asymmetry induced by transfinite partitions makes it impossible for Jordan curves to have an infinite length.

Antonio Leon

2006-08-21T23:59:59.000Z

71

A Dynamic Reversal Bending Fatigue Testing System  

A bending fatigue system has been proposed and developed in this disclosure to test various structural materials in general.

72

Integrative Materials Design: Performance and Sustainability  

Science Conference Proceedings (OSTI)

Effects of Hot Compressive Dwell Condition on the Fatigue Crack Growth Response of Cast Aluminum ... Multi-Scale Design of Open-Cell Aluminum Alloy Foam.

73

Mechanical fatigue analysis of gold microbeams for RF-MEMS applications by pull-in voltage monitoring  

Science Conference Proceedings (OSTI)

This work is focused on the reliability of gold microcantilevers under the effect of mechanical fatigue. A dedicated device for testing the material is designed and built; the material degradation is monitored during the tests by means of a novel technique ... Keywords: Failure analysis, Fatigue, Gold, MEMS, Reliability

G. Pasquale; A. Somà; A. Ballestra

2009-12-01T23:59:59.000Z

74

Fatigue of Composite Materials and Substructures for Wind Turbine Blades  

DOE Green Energy (OSTI)

This report presents the major findings of the Montana State University Composite Materials Fatigue Program from 1997 to 2001, and is intended to be used in conjunction with the DOE/MSU Composite Materials Fatigue Database. Additions of greatest interest to the database in this time period include environmental and time under load effects for various resin systems; large tow carbon fiber laminates and glass/carbon hybrids; new reinforcement architectures varying from large strands to prepreg with well-dispersed fibers; spectrum loading and cumulative damage laws; giga-cycle testing of strands; tough resins for improved structural integrity; static and fatigue data for interply delamination; and design knockdown factors due to flaws and structural details as well as time under load and environmental conditions. The origins of a transition to increased tensile fatigue sensitivity with increasing fiber content are explored in detail for typical stranded reinforcing fabrics. The second focus of the report is on structural details which are prone to delamination failure, including ply terminations, skin-stiffener intersections, and sandwich panel terminations. Finite element based methodologies for predicting delamination initiation and growth in structural details are developed and validated, and simplified design recommendations are presented.

MANDELL, JOHN F.; SAMBORSKY, DANIEL D.; CAIRNS, DOUGLAS

2002-03-01T23:59:59.000Z

75

Parametric System Curves: Correlations Between Fan Pressure Rise and Flow for Large Commercial Buildings  

E-Print Network (OSTI)

distribution, duct design, system curve, fans, leakage iiifan pressure rise and flow measurements over a range of operating conditions. During design,

Sherman, Max

2010-01-01T23:59:59.000Z

76

Report on Assessment of Environmentally--Assisted Fatigue for LWR Extended  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

on Assessment of Environmentally--Assisted Fatigue for LWR on Assessment of Environmentally--Assisted Fatigue for LWR Extended Service Conditions Report on Assessment of Environmentally--Assisted Fatigue for LWR Extended Service Conditions This report provides an update on the assessment of environmentally-assisted fatigue for light water reactor (LWR) extended service conditions. The report is a deliverable in FY11 under the work package for LWRS under the Advanced Reactor Concepts. Most of the current fleet of aging LWRs were designed using the 1970s version of the ASME Boiler and Pressure Vessels Code, Section III, and are reaching their design lifetime of 30-40 yrs. For economic reasons, the utilities have great interest in extending the operating life of the plants via the Nuclear Regulatory Commission (NRC) licensing renewal application

77

Report on Assessment of Environmentally--Assisted Fatigue for LWR Extended  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

on Assessment of Environmentally--Assisted Fatigue for LWR on Assessment of Environmentally--Assisted Fatigue for LWR Extended Service Conditions Report on Assessment of Environmentally--Assisted Fatigue for LWR Extended Service Conditions This report provides an update on the assessment of environmentally-assisted fatigue for light water reactor (LWR) extended service conditions. The report is a deliverable in FY11 under the work package for LWRS under the Advanced Reactor Concepts. Most of the current fleet of aging LWRs were designed using the 1970s version of the ASME Boiler and Pressure Vessels Code, Section III, and are reaching their design lifetime of 30-40 yrs. For economic reasons, the utilities have great interest in extending the operating life of the plants via the Nuclear Regulatory Commission (NRC) licensing renewal application

78

Bilipschitz Homogeneity and Jordan Curves.  

E-Print Network (OSTI)

??We analyze Jordan curves in the plane that are bilipschitz homogeneous with respect to Euclidean distance and/or inner diameter distance. We begin our analysis from… (more)

Freeman, David M.

2009-01-01T23:59:59.000Z

79

Motor Systems Efficiency Supply Curves  

NLE Websites -- All DOE Office Websites (Extended Search)

expert opinion and available data from the United States, Canada, the European Union, Thailand, Vietnam, and Brazil, bottom-up energy efficiency supply curve models were...

80

Snap rounding of Bézier curves  

Science Conference Proceedings (OSTI)

We present an extension of snap roundingfrom straight-line segments (see Guibas and Marimont, 1998)to Bézier curves of arbitrary degree, and thus the first method for geometric roundingof curvilinear arrangements.Our algorithm takes a set of intersecting ... Keywords: Bézier curves, arrangement, geometric rounding, intersection computation, robustness, snap rounding, splines

Arno Eigenwillig; Lutz Kettner; Nicola Wolpert

2007-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Evaluation of Thermal Fatigue Effects on Systems Requiring Aging Management Review for License Renewal for the Calvert Cliffs Nuclear Power Plant  

Science Conference Proceedings (OSTI)

In recent years, the nuclear power industry has devoted significant attention to metal fatigue and its impact on the design qualification and serviceability of operating components. This study provides a pilot plant demonstration of the current industry technical position on fatigue evaluation for license renewal, specifically addressing reactor water environmental effects. It also develops a technical evaluation method for determining fatigue life adequacy in a feedwater piping system, a pressurizer sur...

1998-02-25T23:59:59.000Z

82

Fatigue in Advanced Materials & Environmental Effects  

Science Conference Proceedings (OSTI)

Mar 6, 2013 ... Local variations in crack growth rate, investigations of fatigue crack .... the first step consists in conduct a finite element analysis in order to ...

83

Parameters Controlling the Thermal Fatigue Properties of ...  

Science Conference Proceedings (OSTI)

component thermal fatigue lifetimes ... with a symmetrical cycle shape maintained for the heating and cooling ... to the surfaces of components to enhance. E o.

84

Ultrasonic Fatigue of Metals and Alloys I  

Science Conference Proceedings (OSTI)

Mar 14, 2012... that combines ultrasonic fatigue instrumentation and Digital Image Correlation ... Closed lock loop control of load amplitude and resonance ...

85

Fatigue Behavior in Monocrystalline Ni-Based Superalloys for Blade ...  

Science Conference Proceedings (OSTI)

fatigue resistance, resulting in the need to better understand the effects of alloy microstructure on fatigue crack initiation and propagation. In this study, sustained  ...

86

Effect of Interstitial Content on High Temperature Fatigue Crack ...  

Science Conference Proceedings (OSTI)

instance; resulted in fatigue crack propagation (FCP)' programs like ESDADTA(2) and ENSIP(3). Fatigue resistance of nickel base superalloys is affected by ...

87

Thermal Cycling on Fatigue Failure of the Plutonium Vitrification Melter  

SciTech Connect

One method for disposition of excess plutonium is vitrification into cylindrical wasteforms. Due to the hazards of working with plutonium, the vitrification process must be carried out remotely in a shielded environment. Thus, the equipment must be easily maintained. With their simple design, induction melters satisfy this criterion, making them ideal candidates for plutonium vitrification. However, due to repeated heating and cooling cycles and differences in coefficients of thermal expansion of contacting materials fatigue failure of the induction melter is of concern. Due to the cost of the melter, the number of cycles to failure is critical. This paper presents a method for determining the cycles to failure for an induction melter by using the results from thermal and structural analyses as input to a fatigue failure model.

Jordan, Jeffrey; Gorczyca, Jennifer

2009-02-11T23:59:59.000Z

88

A ROBUST TOPOLOGICAL PRELIMINARY DESIGN EXPLORATION METHOD WITH MATERIALS DESIGN  

E-Print Network (OSTI)

­ Volume ­ Cost ­ Performance · Balance-of-plant (BOP) components ­ Weight ­ Cost ­ Availability, and composite layup · Measure tank strength and fatigue life #12;Track 1: Optimization of materials & design

89

Modeling Thermal Fatigue in CPV Cell Assemblies (Presentation)  

DOE Green Energy (OSTI)

This presentation outlines the modeling of thermal fatigue in concentrating photovoltaic (CPV) assemblies.

Bosco, N.; Panchagade, D.; Kurtz, S.

2011-02-01T23:59:59.000Z

90

Accelerating Fatigue Testing for Cu Ribbon Interconnects (Presentation)  

DOE Green Energy (OSTI)

This presentation describes fatigue experiments and discusses dynamic mechanical loading for Cu ribbon interconnects.

Bosco, N.; Silverman, T.; Wohlgemuth , J.; Kurtz, S.; Inoue, M.; Sakurai, K.; Shioda, T.; Zenkoh, H.; Miyashita, M.; Tadanori, T.; Suzuki, S.

2013-05-01T23:59:59.000Z

91

Design  

NLE Websites -- All DOE Office Websites (Extended Search)

Design Design of a Multithreaded Barnes-Hut Algorithm for Multicore Clusters Technical Report Junchao Zhang and Babak Behzad Department of Computer Science, University of Illinois at Urbana-Champaign {jczhang, bbehza2}@illinois.edu Marc Snir Department of Computer Science, University of Illinois at Urbana-Champaign and MCS Division, Argonne National Laboratory snir@anl.gov Abstract We describe in this paper an implementation of the Barnes-Hut al- gorithm on multicore clusters. Based on a partitioned global ad- dress space (PGAS) library, the design integrates intranode mul- tithreading and internode one-sided communication, exemplifying a PGAS + X programming style. Within a node, the computation is decomposed into tasks (subtasks), and multitasking is used to hide network latency. We study the tradeoffs between locality in private caches and locality in shared caches

92

Incorporating Experience Curves in Appliance Standards Analysis  

E-Print Network (OSTI)

experience curves for wind farms. Energy Policy 33, 133-150.curves for wind power. Energy Policy 30, 1181- Jakob, M. ,

Desroches, Louis-Benoit

2012-01-01T23:59:59.000Z

93

DOE/MSU composite material fatigue database: Test methods, materials, and analysis  

DOE Green Energy (OSTI)

This report presents a detailed analysis of the results from fatigue studies of wind turbine blade composite materials carried out at Montana State University (MSU) over the last seven years. It is intended to be used in conjunction with the DOE/MSU composite Materials Fatigue Database. The fatigue testing of composite materials requires the adaptation of standard test methods to the particular composite structure of concern. The stranded fabric E-glass reinforcement used by many blade manufacturers has required the development of several test modifications to obtain valid test data for materials with particular reinforcement details, over the required range of tensile and compressive loadings. Additionally, a novel testing approach to high frequency (100 Hz) testing for high cycle fatigue using minicoupons has been developed and validated. The database for standard coupon tests now includes over 4,100 data points for over 110 materials systems. The report analyzes the database for trends and transitions in static and fatigue behavior with various materials parameters. Parameters explored are reinforcement fabric architecture, fiber content, content of fibers oriented in the load direction, matrix material, and loading parameters (tension, compression, and reversed loading). Significant transitions from good fatigue resistance to poor fatigue resistance are evident in the range of materials currently used in many blades. A preliminary evaluation of knockdowns for selected structural details is also presented. The high frequency database provides a significant set of data for various loading conditions in the longitudinal and transverse directions of unidirectional composites out to 10{sup 8} cycles. The results are expressed in stress and strain based Goodman Diagrams suitable for design. A discussion is provided to guide the user of the database in its application to blade design.

Mandell, J.F.; Samborsky, D.D. [Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering

1997-12-01T23:59:59.000Z

94

Substrate Creep on The Fatigue Life of A Model Dental Multilayer Structure  

SciTech Connect

In this paper, we investigated the effects of substrate creep on the fatigue behavior of a model dental multilayer structure, in which a top glass layer was bonded to a polycarbonate substrate through a dental adhesive. The top glass layers were ground using 120 grit or 600 grit sand papers before bonding to create different sub-surface crack sizes and morphologies. The multilayer structures were tested under cyclic Hertzian contact loading to study crack growth and obtain fatigue life curves. The experiment results showed that the fatigue lives of the multilayer structures were impaired by increasing crack sizes in the sub-surfaces. They were also significantly reduced by the substrate creep when tested at relatively low load levels i.e. P{sub m} < 60 N (Pm is the maximum magnitude of cyclic load). But at relatively high load levels i.e. P{sub m} > 65 N, slow crack growth (SCG) was the major failure mechanisms. A modeling study was then carried out to explore the possible failure mechanisms over a range of load levels. It is found that fatigue life at relatively low load levels can be better estimated by considering the substrate creep effect (SCE).

Zhou, J; Huang, M; Niu, X; soboyejo, W

2006-10-09T23:59:59.000Z

95

Substrate Creep on The Fatigue Life of A Model Dental Multilayer Structure  

Science Conference Proceedings (OSTI)

In this paper, we investigated the effects of substrate creep on the fatigue behavior of a model dental multilayer structure, in which a top glass layer was bonded to a polycarbonate substrate through a dental adhesive. The top glass layers were ground using 120 grit or 600 grit sand papers before bonding to create different sub-surface crack sizes and morphologies. The multilayer structures were tested under cyclic Hertzian contact loading to study crack growth and obtain fatigue life curves. The experiment results showed that the fatigue lives of the multilayer structures were impaired by increasing crack sizes in the sub-surfaces. They were also significantly reduced by the substrate creep when tested at relatively low load levels i.e. P{sub m} 65 N, slow crack growth (SCG) was the major failure mechanisms. A modeling study was then carried out to explore the possible failure mechanisms over a range of load levels. It is found that fatigue life at relatively low load levels can be better estimated by considering the substrate creep effect (SCE).

Zhou, J; Huang, M; Niu, X; soboyejo, W

2006-10-09T23:59:59.000Z

96

Fatigue  

Science Conference Proceedings (OSTI)

Figure: ...as open symbols, whereas cyclic conditions that led to fracture at <10 7 cycles are represented with closed symbols. The 10 7 cycle

97

Supply Curves of Conserved Energy  

SciTech Connect

Supply curves of conserved energy provide an accounting framework that expresses the potential for energy conservation. The economic worthiness of a conservation measure is expressed in terms of the cost of conserved energy, and a measure is considered economical when the cost of conserved energy is less than the price of the energy it replaces. A supply curve of conserved energy is independent of energy prices; however, the economical reserves of conserved energy will depend on energy prices. Double-counting of energy savings and error propagation are common problems when estimating conservation potentials, but supply curves minimize these difficulties and make their consequences predictable. The sensitivity of the cost of conserved energy is examined, as are variations in the optimal investment strategy in response to changes in inputs. Guidelines are presented for predicting the consequences of such changes. The conservation supply curve concept can be applied to peak power, water, pollution, and other markets where consumers demand a service rather than a particular good.

Meier, Alan Kevin

1982-05-01T23:59:59.000Z

98

The High Cycle Fatigue and Final Fracture Behavior of Alloy Steel ...  

Science Conference Proceedings (OSTI)

Energy Based Fatigue Life Prediction Models and Methods for Combined Low Cycle and High Cycle Fatigue · Fatigue Behavior of AM60B Subjected to Variable  ...

99

Sensitivity of Solder Joint Fatigue to Sources of Variation in Advanced Vehicular Power Electronics Cooling  

SciTech Connect

This paper demonstrates a methodology for taking variation into account in thermal and fatigue analyses of the die attach for an inverter of an electric traction drive vehicle. This method can be used to understand how variation and mission profile affect parameters of interest in a design. Three parameters are varied to represent manufacturing, material, and loading variation: solder joint voiding, aluminum nitride substrate thermal conductivity, and heat generation at the integrated gate bipolar transistor. The influence of these parameters on temperature and solder fatigue life is presented. The heat generation loading variation shows the largest influence on the results for the assumptions used in this problem setup.

Vlahinos, A.; O' Keefe, M.

2010-06-01T23:59:59.000Z

100

TRANSFINITE PARTITIONS OF JORDAN CURVES  

E-Print Network (OSTI)

Abstract. The ?-asymmetry induced by transfinite partitions makes it impossible for Jordan curves to have an infinite length. 1. ?-asymmetry As we known from the XVIII century, ?-partitions (as we call them nowadays) of finite line segments are only possible if the successive adjacent parts of the ?-partition are of a decreasing length. This inevitable restriction induces a huge asymmetry in the very partition. In fact, whatever be the length of the ?-partitioned line segment and whatever be the ?-partition, all its parts, except a finite number of them, will necessarily lie within an arbitrarily small final segment. For the sake of illustration, consider an ?-partition of a 10 30 light years length segment-the assumed diameter of the universe. Whatever be the ?-partition of this enormous line segment all its infinitely many parts, except a finite number of them, will inevitably lie within a final segment inconceivable less than, for instance, Planck length ( ? 10 ?33 cm). There is no way of performing a more equitable partition if the partition has to be ?-ordered. Thus, ?-partitions are ?-asymmetrical. For the same reason it is impossible to consider two proper points in the real line R separated by an infinite euclidean distance, in spite of the assumed infiniteness of the real line. The above simply unaesthetic consequences of ?-partitions become a little more controversial if the partitioned object is a closed line as a Jordan curve. The objective of the following short discussion is just to examine one of those consequences. Figure 1. A cosmic ?-asymmetry. The ?-order makes it impossible a more equitable distribution of the available space. 1 2 Transfinite partitions of Jordan Curves 2. Transfinite partitions of Jordan Curves Let f(x) be a real valued function whose graph is a Jordan Curve J in the euclidean plane R2. If a and b are any two J’s points, we will write L(a, b) to denote the length of the J’s arc ãb whose endpoints are a and b. That is to say: b ? L(a, b) = 1 + (f(x)?) 2dx (1)

Antonio Leon Sanchez; I. E. S. Francisco; Salinas Salamanca

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Application of measured loads to wind turbine fatigue and reliability analysis  

DOE Green Energy (OSTI)

Cyclic loadings produce progressive damage that can ultimately result in wind turbine structural failure. There are many issues that must be dealt with in turning load measurements into estimates of component fatigue life. This paper deals with how the measured loads can be analyzed and processed to meet the needs of both fatigue life calculations and reliability estimates. It is recommended that moments of the distribution of rainflow-range load amplitudes be calculated and used to characterize the fatigue loading. These moments reflect successively more detailed physical characteristics of the loading (mean, spread, tail behavior). Moments can be calculated from data samples and functional forms can be fitted to wind conditions, such as wind speed and turbulence intensity, with standard recession techniques. Distributions of load amplitudes that accurately reflect the damaging potential of the loadings can be estimated from the moments at any, wind condition of interest. Fatigue life can then be calculated from the estimated load distributions, and the overall, long-term, or design spectrum can be generated for any particular wind-speed distribution. Characterizing the uncertainty in the distribution of cyclic loads is facilitated by using a small set of descriptive statistics for which uncertainties can be estimated. The effects of loading parameter uncertainty can then be transferred to the fatigue life estimate and compared with other uncertainties, such as material durability.

Veers, P.S. [Sandia National Labs., Albuquerque, NM (United States); Winterstein, S.R. [Stanford Univ., CA (United States)

1997-01-01T23:59:59.000Z

102

A Review of Stress Corrosion Cracking/Fatigue Modeling for Light Water  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

A Review of Stress Corrosion Cracking/Fatigue Modeling for Light A Review of Stress Corrosion Cracking/Fatigue Modeling for Light Water Reactor Cooling System Components A Review of Stress Corrosion Cracking/Fatigue Modeling for Light Water Reactor Cooling System Components In the United States currently there are approximately 104 operating light water reactors. Of these, 69 are pressurized water reactors (PWRs) and 35 are boiling water reactors (BWRs). In 2007, the 104 light-water reactors (LWRs) in the United States generated approximately 100 GWe, equivalent to 20% of total US electricity production. Most of the US reactors were built before 1970 and the initial design lives of most of the reactors are 40 years. It is expected that by 2030, even those reactors that have received 20-year life extension license from the US Nuclear Regulatory Commission

103

Regression Error Characteristic CurVes  

E-Print Network (OSTI)

Receiver Operating Characteristic (ROC) curves provide a powerful tool for visualizing and comparing classification results. Regression Error Characteristic (REC) curves generalize ROC curves to regression. REC curves plot the error tolerance on the xaxis versus the percentage of points predicted within the tolerance on the y-axis. The resulting curve estimates the cumulative distribution function of the error. The REC curve visually presents commonly-used statistics. The area-over-the-curve (AOC) is a biased estimate of the expected error. The R 2 value can be estimated using the ratio of the AOC for a given model to the AOC for the null model. Users can quickly assess the relative merits of many regression functions by examining the relative position of their REC curves. The shape of the curve reveals additional information that can be used to guide modeling. 1.

Jinbo Bi; Kristin P. Bennett

2003-01-01T23:59:59.000Z

104

Swept measurement of high power I-V curves  

SciTech Connect

Performance evaluation of photovoltaic (PV) arrays under a variety of conditions provides important information for the design and maintenance of PV systems. One of the principal methods for assessing an array's performance is to plot its current, I, versus voltage, V, curve. Following a brief review of techniques for measuring the I-V curve, a new capacitive-based approach is presented. It uses a rapid sweep of the I-V curve which substantially reduces the average power transfer between array and load, and in turn, substantially reduces the size and weight of the curve tracer. Both theoretical and practical aspects of the approach are presented for a 10-kW unit. Performance is verified by comparison with I-V curves obtained by using a conventional load. The agreement is found to be excellent. Approximately an order of magnitude reduction in size, weight and power consumption over conventional units was realized with the experimental I-V curve tracer.

Cox, C.H.; Warner, T.H.

1982-09-01T23:59:59.000Z

105

Swept measurement of high-power I-V curves  

SciTech Connect

Performance evaluation of photovoltaic (PV) arrays under a variety of conditions provides important information for the design and maintenance of PV systems. One of the principal methods for assessing an arrays's performance is to plot its current, I, versus voltage, V, curve. Following a brief review of techniques for measuring the I-V curve, a new capacitive-based approach is presented. It uses a rapid sweep of the I-V curve which substantially reduces the average power transfer between array and load, and in turn, substantially reduces the size and weight of the curve tracer. Both theoretical and practical aspects of the approach are presented for a 10-kW unit. Performance is verified by comparison with I-V curves obtained by using a conventional load. The agreement is found to be excellent. Approximately an order of magnitude reduction in size, weight and power consumption over conventional units was realized with the experimental I-V curve tracer.

Cox, C.H. III; Warner, T.H.

1982-01-01T23:59:59.000Z

106

Failure by fracture and fatigue in "NANO" and "BIO" materials  

E-Print Network (OSTI)

AND FATIGUE IN “NANO” AND “BIO” MATERIALS R. O. Ritchie, 1,3and Fatigue in “Nano” and “Bio” Materials R. O. Ritchie 1 ,structures and biologi- cal/bio-implantable materials, so-

Ritchie, R.O.; Muhlstein, C.L.; Nalla, R.K.

2003-01-01T23:59:59.000Z

107

FATIGUEPRO: On-Line Fatigue Usage Transient Monitoring System  

Science Conference Proceedings (OSTI)

FATIGUEPRO accurately monitors plant data to calculate actual fatigue usage for critical nuclear plant components. This system should improve plant reliability and contribute to plant life extension by providing a more realistic estimation of fatigue demands.

1988-05-01T23:59:59.000Z

108

High Cycle Fatigue in a Single Crystal Superalloy: Time ...  

Science Conference Proceedings (OSTI)

Keywords: Single crystal superalloys, High cycle fatigue, Environmental coatings, Rupture ... modes were modeled separately and then combined into a damage.

109

On the Fatigue Crack Propagation Behavior of Superalloys at ...  

Science Conference Proceedings (OSTI)

ON THE FATIGUE CRACK PROPAGATION BEHAVIOR. OF SUPERALLOYS AT ... the FCP resistance of superalloys ... lead to poor crack propagation behavior.

110

Constant-amplitude fatigue-life data for notched and unnotched annealed ti-6al-4v sheet. Final report, January 1983-September 1986  

Science Conference Proceedings (OSTI)

Three lots of annealed Ti-6A1-4V sheet material in thicknesses of 0.063, 0.070, and 0.078 inch, supplied by two manufacturers, were tested to develop fatigue life curves for MIL-HDBK-5. Notched (Kt=3.0) and unnotched configurations of longitudinal and transverse specimens were tested at R ratios of +0.5, +0.1, and -0.5. Fatigue-life data are presented in both tabular and graphical forms. Results are presented in both tabular and graphical forms. Results were forwarded to the Battelle Memorial Institute, Columbus, Ohio, for analysis, reduction, and inclusion in MIL-HDBK-5.

Rhode, T.M.; Ertel, P.W.

1988-01-01T23:59:59.000Z

111

Fatigue reliability of wind turbine components  

DOE Green Energy (OSTI)

Fatigue life estimates for wind turbine components can be extremely variable due to both inherently random and uncertain parameters. A structural reliability analysis is used to qualify the probability that the fatigue life will fall short of a selected target. Reliability analysis also produces measures of the relative importance of the various sources of uncertainty and the sensitivity of the reliability to each input parameter. The process of obtaining reliability estimates is briefly outlined. An example fatigue reliability calculation for a blade joint is formulated; reliability estimates, importance factors, and sensitivities are produced. Guidance in selecting distribution functions for the random variables used to model the random and uncertain parameters is also provided. 5 refs., 9 figs., 1 tab.

Veers, P.S.

1990-01-01T23:59:59.000Z

112

Fatigue of Composite Material Beam Elements Representative of Wind Turbine Blade Substructure  

DOE Green Energy (OSTI)

The database and analysis methods used to predict wind turbine blade structural performance for stiffness, static strength, dynamic response,and fatigue lifetime are validated through the design, fabrication, and testing of substructural elements. We chose a test specimen representative of wind turbine blade primary substructure to represent the spar area of a typical wind turbine blade. We then designed an I-beam with flanges and web to represent blade structure, using materials typical of many U.S.-manufactured blades. Our study included the fabrication and fatigue testing of 52 beams and many coupons of beam material. Fatigue lifetimes were consistent with predictions based on the coupon database. The final beam specimen proved to be a very useful tool for validating strength and lifetime predictions for a variety of flange and web materials, and is serving as a test bed to ongoing studies of structural details and the interaction between manufacturing and structural performance. Th e beam test results provide a significant validation of the coupon database and the methodologies for predicting fatigue of composite material beam elements.

Mandell, J. F.; Samborsky, D. D.; Combs, D. W.; Scott, M. E.; Cairns, D. S. (Department of Chemical Engineering, Montana State University)

1998-01-11T23:59:59.000Z

113

Conductor assembly formed about a curved axis  

DOE Patents (OSTI)

A conductor assembly of the type which, when conducting current, generates a magnetic field or in which, in the presence of a changing magnetic field, a voltage is induced. In the assembly a first layer, tubular in shape, is formed about an axis. The axis includes a curved portion along which a conductor may be positioned to define a first conductor path. The first layer also includes a curved portion having a shape that includes a curve extending along the curved portion of the axis. A first conductor is arranged about the curved portion of the first layer in a first helical configuration including a curved segment, helical in shape and formed about the curved portion of the axis. The configuration is capable of sustaining a magnetic field having multipole components oriented in directions transverse to the axis.

Meinke, Rainer (Melbourne, FL)

2011-02-15T23:59:59.000Z

114

Fatigue of Wind Blade Laminates:Fatigue of Wind Blade Laminates: Effects of Resin and Fabric Structure  

E-Print Network (OSTI)

Fatigue of Wind Blade Laminates:Fatigue of Wind Blade Laminates: Effects of Resin and Fabric University MCARE 2012 #12;Outline · Overview of MSU Fatigue Program on Wind Blade MaterialsWind Blade Wind Blade Component Materials Acknowledgements: Sandia National Laboratories/DOE (Joshua Paquette

115

Alternative procedures for J-R curve determination  

SciTech Connect

This investigation evaluates alternative displacement techniques with the single-specimen compliance (SSC) procedure which do not require the commonly used load-line displacement measurements in a compact toughness (CT) specimen to determine the J-R curve. The two techniques studied are a double-clip-gage technique involving both crack-mouth displacement and load-line displacement at the edges of the specimen and a technique which requires only crack-mouth displacement. R-curves developed using these techniques are compared to R-curves developed with the normal load-line based deflections. In addition, results of a round-robin program using the SSC procedure are discussed in terms of validating the double-clip-gage technique. R-curves developed from crack-mouth displacements on the J-integral specimen from ASTM E 813 suggest that the standard ASTM E 399 specimen design can be used for both linear-elastic (e.g., K/sub Ic/) and elastic-plastic (e.g., R-curve toughness assessments.

Hiser, A.L.; Loss, F.J.

1983-07-01T23:59:59.000Z

116

Quantifying the Thermal Fatigue of CPV Modules  

DOE Green Energy (OSTI)

A method is presented to quantify thermal fatigue in the CPV die-attach from meteorological data. A comparative; study between cities demonstrates a significant difference in the accumulated damage. These differences are most; sensitive to the number of larger (?T) thermal cycles experienced for a location. High frequency data (<1/min) may; be required to most accurately employ this method.

Bosco, N.; Kurtz, S.

2011-02-01T23:59:59.000Z

117

Certified Approximation of Parametric Space Curves with Cubic B-spline Curves  

E-Print Network (OSTI)

Approximating complex curves with simple parametric curves is widely used in CAGD, CG, and CNC. This paper presents an algorithm to compute a certified approximation to a given parametric space curve with cubic B-spline curves. By certified, we mean that the approximation can approximate the given curve to any given precision and preserve the geometric features of the given curve such as the topology, singular points, etc. The approximated curve is divided into segments called quasi-cubic B\\'{e}zier curve segments which have properties similar to a cubic rational B\\'{e}zier curve. And the approximate curve is naturally constructed as the associated cubic rational B\\'{e}zier curve of the control tetrahedron of a quasi-cubic curve. A novel optimization method is proposed to select proper weights in the cubic rational B\\'{e}zier curve to approximate the given curve. The error of the approximation is controlled by the size of its tetrahedron, which converges to zero by subdividing the curve segments. As an applic...

Shen, Liyong; Gao, Xiao-Shan

2012-01-01T23:59:59.000Z

118

Mechanical behavior analysis of CDIO production-blood vessel robot in curved blood vessel  

Science Conference Proceedings (OSTI)

In order to analyze mechanical behavior of blood vessel robot (student's CDIO production) in curved blood, and provide the data for outline design of robot, the flow field out side of robot is numerical simulated. The results show that the vessel shape ... Keywords: blood vessel robot, curved blood vessel, mechanical behavior analysis, numerical simulation

Fan Jiang; Chunliang Zhang; Yijun Wang

2010-10-01T23:59:59.000Z

119

Mean Stress and Environmental Effects on Fatigue in Type 304 Stainless Steel  

SciTech Connect

Fatigue life tests were performed in air on Type 304 stainless steel (304 SS) to establish the effect of mean stress under both load control and strain control. An apparent reduction of up to 26% in strain-amplitude occurred in the low and intermediate cycle regime (< 10{sup 8} cycles) for a mean stress of 138 Mpa. A quantitative description of mean stress effects using the Smith-Watson-Topper equivalent strain parameter was developed, which incorporates mean stress through the maximum stress. This description provided a tighter fit to the data, and allowed separation of mean stress and cold work effects. With this separation, the effect of mean stress was reduced to 12% decrease in strain amplitude at 138 Mpa. The stress-life curve apparently increased with increasing mean stress, due to the significant work hardening that occurred in tests with high mean stresses, especially under load control. Tests were performed on double-edge notched specimens of 304 SS in air and low oxygen water at 288 C. The elastically calculated increase in the notch tip stress accounted within 10% for the fatigue life reductions for a K{sub t} = 4.8 notch, but was 38% conservative for a K{sub t} = 8.8 notch. Fatigue crack initiation lives (defined as an 0.127 mm crack) in low oxygen water at 288 C were reduced by a factor of four to eight on cycles over those in air. Crack growth occurred throughout most of the fatigue ''initiation'' life. The increase in crack growth rate of 304 SS in water appears to be large enough to explain the reduced ''initiation'' life in this environment.

Kandra, J.T.; Leax, T.R.; Wire, G.L.

1999-04-01T23:59:59.000Z

120

Trends in electric utility load duration curves  

SciTech Connect

This report documents the development and analysis of annual and quarterly load duration curves for each of the 10 Federal regions. The report describes analyses performed to test for changes in load duration curve shapes over time. These analyses are intended to aid the electric utility analyses and modeling activities of the Energy Information Administration (EIA) by expanding the understanding of current and expected load duration curve shapes. 7 figs., 13 tabs.

1984-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Bayesian methods for estimating ROC curves.  

E-Print Network (OSTI)

?? Receiver operating characteristic (ROC) analysis is a fundamental method for assessing imaging systems. However, clinical trials to estimate ROC curves can be costly as… (more)

Zur, Richard Michael

2011-01-01T23:59:59.000Z

122

Adaptive mesh generation for curved domains  

Science Conference Proceedings (OSTI)

This paper considers the technologies needed to support the creation of adaptively constructed meshes for general curved three-dimensional domains and outlines one set of solutions for providing them. A brief review of an effective way to integrate mesh ... Keywords: adaptive meshes, anisotropic meshes, curved meshes

Mark S. Shephard; Joseph E. Flaherty; Kenneth E. Jansen; Xiangrong Li; Xiaojuan Luo; Nicolas Chevaugeon; Jean-François Remacle; Mark W. Beall; Robert M. O'Bara

2005-02-01T23:59:59.000Z

123

Mathematical modelling of brown seaweed drying curves  

Science Conference Proceedings (OSTI)

Simple solution on one-term exponential models is used in the analysis of raw data obtained from the drying experiment. The values of the parameters a, n and the constant k for the models are determined using a plot of curve drying models. Three different ... Keywords: brown seaweed, drying curves, mathematical models

Ahmad Fudholi; Mohd Hafidz Ruslan; Lim Chin Haw; Sohif Mat; Mohd Yusof Othman; Azami Zaharim; Kamaruzzaman Sopian

2012-01-01T23:59:59.000Z

124

Active curve axis Gaussian mixture models  

Science Conference Proceedings (OSTI)

Gaussian Mixture Models (GMM) have been broadly applied for the fitting of probability density function. However, due to the intrinsic linearity of GMM, usually many components are needed to appropriately fit the data distribution, when there are curve ... Keywords: AcaG, AcaGMM, Active curve axis, EM, Finite mixture models, GMM, Unsupervised learning

Baibo Zhang; Changshui Zhang; Xing Yi

2005-12-01T23:59:59.000Z

125

Bayesian curve estimation by model averaging  

Science Conference Proceedings (OSTI)

A Bayesian approach is used to estimate a nonparametric regression model. The main features of the procedure are, first, the functional form of the curve is approximated by a mixture of local polynomials by Bayesian model averaging (BMA), second, the ... Keywords: BIC criterion, Bayesian model averaging, Local polynomial regression, Nonparametric curve fitting, Robustness

Daniel Peña; Dolores Redondas

2006-02-01T23:59:59.000Z

126

PARAMETRIC MODELS FOR ESTIMATING WIND TURBINE FATIGUE LOADS FOR DESIGN  

E-Print Network (OSTI)

. Veers2 Steven R. Winterstein3 1 Department of Civil Engineering, University of Texas at Austin, Austin, TX 78712 2 Sandia National Laboratories, Wind Energy Technology Department, Albuquerque, NM 87185

Sweetman, Bert

127

Systems approach to the design of locomotive fatigue management technologies  

E-Print Network (OSTI)

Falling asleep while operating a vehicle leads to serious accidents and loss of lives. The challenge of detecting drowsiness nonintrusively stems from the absence of a single marker, and the existence of diverse signs and ...

Aboukhalil, Anton

2006-01-01T23:59:59.000Z

128

Fatigue and Creep-Fatigue Deformation of an Ultra-Fine Precipitate Strengthened Advanced Austenitic Alloy  

SciTech Connect

An advanced austenitic alloy, HT-UPS (high-temperature ultrafine-precipitation-strengthened), has been identified as an ideal candidate material for the structural components of fast reactors and energy-conversion systems. HT-UPS alloys demonstrate improved creep resistance relative to 316 stainless steel (SS) through additions of Ti and Nb, which precipitate to form a widespread dispersion of stable nanoscale metallic carbide (MC) particles in the austenitic matrix. The low-cycle fatigue and creep-fatigue behavior of an HT-UPS alloy have been investigated at 650 °C and a 1.0% total strain, with an R-ratio of -1 and hold times at peak tensile strain as long as 150 min. The cyclic deformation response of HT-UPS is directly compared to that of standard 316 SS. The measured values for total cycles to failure are similar, despite differences in peak stress profiles and in qualitative observations of the deformed microstructures. Crack propagation is primarily transgranular in fatigue and creep-fatigue of both alloys at the investigated conditions. Internal grain boundary damage in the form of fine cracks resulting from the tensile hold is present for hold times of 60 min and longer, and substantially more internal cracks are quantifiable in 316 SS than in HT-UPS. The dislocation substructures observed in the deformed material differ significantly; an equiaxed cellular structure is observed in 316 SS, whereas in HT-UPS the microstructure takes the form of widespread and relatively homogenous tangles of dislocations pinned by the nanoscale MC precipitates. The significant effect of the fine distribution of precipitates on observed fatigue and creep-fatigue response is described in three distinct behavioral regions as it evolves with continued cycling.

M.C. Carroll; L.J. Carroll

2012-10-01T23:59:59.000Z

129

Influence of Microstructure on Fatigue Properties of Alloy 718  

Science Conference Proceedings (OSTI)

combination of the various phases that may be present in the microstructure. ... smooth and notch high cycle fatigue behavior at room temperature and 650°C is  ...

130

Sustained Peak Low Cycle Fatigue: The Role of Coatings  

Science Conference Proceedings (OSTI)

The growth process continued by a combined process of oxidation and creep. ... of a model developed for crack growth during sustained peak low cycle fatigue.

131

An Energy-Based Microstructure Model to Account for Fatigue ...  

Science Conference Proceedings (OSTI)

A Quantitative Crystallographic Model for Fatigue Crack Propagation through ... Effect of Temperature on The Loss of Ductility of S-135 Grade Drill Pipe Steel ...

132

High Cycle Fatigue Behavior of Shot-Peened Steels  

Science Conference Proceedings (OSTI)

A Quantitative Crystallographic Model for Fatigue Crack Propagation through ... Effect of Temperature on The Loss of Ductility of S-135 Grade Drill Pipe Steel ...

133

High Temperature Corrosion Fatigue and Grain Size Control in ...  

Science Conference Proceedings (OSTI)

diesel engines and so on, are inevitably subjected to the simultaneous effects of both the mechanical damages such as creep and/or fatigue and the corrosive.

134

Thermal fatigue evaluation of solder alloys. Final report  

SciTech Connect

An evaluation was made of the relative thermal fatigue resistance of 29 solder alloys. A number of these alloys were found to be less susceptible to thermal fatigue cracking in encapsulated printed wiring board applications than the commonly used tin-lead eutectic (63Sn-37Pb). Three alloys, 95Sn-5Ag, 96.5Sn-3.5Ag, and 95Sn-5Sb offered the greatest resistance to thermal fatigue. The selection of the encapsulation materials was confirmed to be a significant factor in thermal fatigue of solder joints, regardless of the solder alloy used.

Jarboe, D.M.

1980-02-01T23:59:59.000Z

135

Structural Changes During Thermal Fatigue of Two Nickel-Based ...  

Science Conference Proceedings (OSTI)

greatly affect the thermal endurance of these heat-resisting alloys. I?. ... factors govern- ing the thermal fatigue behavior of a number of commercial nickel-.

136

Low-Cycle Fatigue Properties of TRIP Steel  

Science Conference Proceedings (OSTI)

Oct 15, 2006 ... AHSS typically have improved fatigue strength over conventional steels and High Strength Steels (HSS) of similar tensile strength. Sample ...

137

Tension and Flex Bending Fatigue of Superelastic Nitinol  

Science Conference Proceedings (OSTI)

Symposium, Shape Memory Alloys. Presentation Title, Tension and Flex Bending Fatigue of Superelastic Nitinol. Author(s), John R Lewandowski, Brian Benini, ...

138

Fatigue Crack Initiation in Alloy 718 at 650 C  

Science Conference Proceedings (OSTI)

gas turbine engine discs, the loss in fatigue life is less severe. ... rotating components such as discs, spacers and cooling plates in gas turbine engines during.

139

General Assessment of Various Types of Fatigue Fracture ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Fatigue cracking accounts for ~90% of service related events encountered in modern gas turbine engine components and must be addressed in ...

140

Fatigue Predictions of Various Joints of Magnesium Alloys  

Science Conference Proceedings (OSTI)

Currently, a front shock tower of passenger vehicle is developed with various magnesium alloys and joining methods. To predict the fatigue behavior of the joints ...

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

High Temperature Fatigue Behavior of Laser Shock Peened ...  

Science Conference Proceedings (OSTI)

Presentation Title, High Temperature Fatigue Behavior of Laser Shock Peened IN718Plus Superalloy. Author(s), Vibhor Chaswal, S R Mannava, Dong Qian, ...

142

Fatigue Property-Microstructure Relationships and Crack Growth  

Science Conference Proceedings (OSTI)

Feb 28, 2011 ... Effect of Microstructure on Fatigue Behavior of Two Pipeline Steels: .... to a transition crack length (LEFM applicable) is approximated using ...

143

Fatigue and Microstructure: A Symposium on Recent Advances  

Science Conference Proceedings (OSTI)

Symposium, Fatigue and Microstructure: A Symposium on Recent Advances. Sponsorship, MS&T Organization. Organizer(s), Amit Shyam, Oak Ridge National  ...

144

Effects of Ultrasonic Nanocrystal Surface Modification on Fatigue ...  

Science Conference Proceedings (OSTI)

Presentation Title, Effects of Ultrasonic Nanocrystal Surface Modification on Fatigue Behavior of SUS316 Austenitic Stainless Steel Tube for Stents. Author(s)  ...

145

Fundamentals of Fatigue Damage and Modeling - Programmaster.org  

Science Conference Proceedings (OSTI)

Feb 28, 2011 ... Fatigue Weak-Link Density and Strength Distribution in High Strength Al Wrought and Cast Alloys: Tongguang Zhai1; Yuanbin Zhang2; ...

146

Characterization of Elevated Temperature Fatigue Crack Growth Rates  

Science Conference Proceedings (OSTI)

temperature fatigue and the crack growth rates may be adequately correlated with the ... During creep crack growth the use of rate dependent elastic/plastic frac-.

147

Treatment effects of the Forsus fatigue resistant device.  

E-Print Network (OSTI)

??Objectives: To evaluate the correction obtained from the Forsus Fatigue Resistant (FRD) device and orthodontic appliances compared to an untreated control group. Methods: Twenty four… (more)

Heinrichs, Dean.

2010-01-01T23:59:59.000Z

148

Comparison of Fatigue and Fracture Properties of Nb- and V ...  

Science Conference Proceedings (OSTI)

In structural applications that are exposed to the environment,? ?such as bridges,? ? wind towers,? ?power transmission towers,? ?even tall buildings,? ?good fatigue ...

149

Fourth International Conference on Very High Cycle Fatigue  

Science Conference Proceedings (OSTI)

Jul 18, 2007 ... Peter K. Liaw, The University of Tennessee, USA. “Fatigue ..... Must-see artifacts include the Lincoln Chair, Kennedy Presidential. Limousine ...

150

Corrosion Fatigue and Crack Propagation of Different Austenitic ...  

Science Conference Proceedings (OSTI)

A FIB Study of the Resistance of Grain Boundaries to Short Fatigue Crack Propagation in Three-Dimensions in High Strength Al Alloys · A Non-Linear Damage ...

151

Enhanced Corrosion Fatigue Resistance of AISI304 Bellows ...  

Science Conference Proceedings (OSTI)

A FIB Study of the Resistance of Grain Boundaries to Short Fatigue Crack Propagation in Three-Dimensions in High Strength Al Alloys · A Non-Linear Damage ...

152

Effect of Thermal-Mechanical Treatment on the Fatigue Crack ...  

Science Conference Proceedings (OSTI)

that fatigue crack propagation (FCP) resistance without holding time has no significant difference between three alloys with 718Plus being the best and 718 the ...

153

Effect of Microstructure and Grain Size on Fatigue Properties of ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Passive metals exposed to fatigue and wear in corrosive ... In order to investigate multi-degradation, an in-house developed lab scale test rig ...

154

Neck curve polynomials in neck rupture model  

SciTech Connect

The Neck Rupture Model is a model that explains the scission process which has smallest radius in liquid drop at certain position. Old fashion of rupture position is determined randomly so that has been called as Random Neck Rupture Model (RNRM). The neck curve polynomials have been employed in the Neck Rupture Model for calculation the fission yield of neutron induced fission reaction of {sup 280}X{sub 90} with changing of order of polynomials as well as temperature. The neck curve polynomials approximation shows the important effects in shaping of fission yield curve.

Kurniadi, Rizal; Perkasa, Yudha S.; Waris, Abdul [Nuclear Physics and Biophysics Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10 Bandung 40132 (Indonesia)

2012-06-06T23:59:59.000Z

155

Fatigue Behavior of AM60B Subjected to Variable Amplitude Loading  

Science Conference Proceedings (OSTI)

Currently, a front shock tower of passenger vehicle is developed with various magnesium alloys. To predict the fatigue behavior of the structure, fatigue ...

156

Cyclic Deformation and Fatigue Cracking Mechanisms of F.C.C. ...  

Science Conference Proceedings (OSTI)

Fatigue Crack Tip Mechanics Following a Tensile Overload · Fatigue Weak-Link Density and Strength Distribution in High Strength Al Wrought and Cast Alloys.

157

Frequency-Domain Synthesis Of The Fatigue Load Spectrum For The Nps 100-Kw Wind Turbine  

E-Print Network (OSTI)

* The LIFE2 code is a fatigue/fracture mechanics code that is specialized to the analysis of wind turbine components. Two frequency-domain stress spectra techniques contained in this code are used to analyze the measured frequency loads spectra from the Northern Power Systems 100-kW turbine. Results of the two techniques are compared to cycle counts obtained directly from time series data. These results provide the wind turbine designer with two techniques for determining the cycle-counts from frequency data and illustrate the accuracy that the designer can expect from various cycle-counting techniques. INTRODUCTION The LIFE2 code is a fatigue/fracture mechanics code that is specialized to the analysis of wind turbine components. 1 This code permits the analysis of both time series 2 and frequency domain data. 3 In the case of the former, a "rainflow counting" algorithm is used to convert time series data into a cycle count matrix suitable for fatigue analysis. For the latter,...

Herbert J. Sutherland; Richard M. Osgood

1992-01-01T23:59:59.000Z

158

Wind turbine blade fatigue tests: lessons learned and application to SHM system development  

DOE Green Energy (OSTI)

This paper presents experimental results of several structural health monitoring (SHM) methods applied to a 9-meter CX-100 wind turbine blade that underwent fatigue loading. The blade was instrumented with piezoelectric transducers, accelerometers, acoustic emission sensors, and foil strain gauges. It underwent harmonic excitation at its first natural frequency using a hydraulically actuated resonant excitation system. The blade was initially excited at 25% of its design load, and then with steadily increasing loads until it failed. Various data were collected between and during fatigue loading sessions. The data were measured over multiple frequency ranges using a variety of acquisition equipment, including off-the-shelf systems and specially designed hardware developed by the authors. Modal response, diffuse wave-field transfer functions, and ultrasonic guided wave methods were applied to assess the condition of the wind turbine blade. The piezoelectric sensors themselves were also monitored using a sensor diagnostics procedure. This paper summarizes experimental procedures and results, focusing particularly on fatigue crack detection, and concludes with considerations for implementing such damage identification systems, which will be used as a guideline for future SHM system development for operating wind turbine blades.

Taylor, Stuart G. [Los Alamos National Laboratory; Farinholt, Kevin M. [Los Alamos National Laboratory; Jeong, Hyomi [Chonbuk National University, Korea; Jang, JaeKyung [Chonbuk National University, Korea; Park, Gyu Hae [Los Alamos National Laboratory; Todd, Michael D. [Los Alamos National Laboratory; Farrar, Charles R. [Los Alamos National Laboratory; Ammerman, Curtt N. [Los Alamos National Laboratory

2012-06-28T23:59:59.000Z

159

Analysis of exoplanetary transit light curves  

E-Print Network (OSTI)

This Thesis considers the scenario in which an extra-solar planet (exoplanet) passes in front of its star relative to our observing perspective. In this event, the light curve measured for the host star features a systematic ...

Carter, Joshua Adam

2009-01-01T23:59:59.000Z

160

Energy flow analysis for curved beams  

Science Conference Proceedings (OSTI)

This paper presents an energy model for the medium- and high-frequency analysis of Love–Kirchhoff curved beams. This model introduced by Nefske and Sung [Statistical Energy Analysis NCA 3

A. Le Bot; M. N. Ichchou; L. Jezequel

1997-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Active learning to maximize area under the ROC curve  

E-Print Network (OSTI)

In active learning, a machine learning algorithm is given an unlabeled set of examples U, and is allowed to request labels for a relatively small subset of U to use for training. The goal of active learning is to judiciously choose which examples in U to have labeled in order to optimize some performance criterion, e.g. generalization accuracy. ROC (Receiver Operating Characteristic) analysis has attracted high attention in machine learning research in the last few years. ROC curves have been advocated and gradually adopted as an al-ternative to classical machine learning metrics such as misclassification rate. We present several heuristics for active learning designed to optimize area under the ROC curve (AUC) and extensively evaluate them, along with other commonly-used active learning algorithms. One of our algorithms (ESTAUC) was the top performer. When good posterior probability estimates were available, ESTAUC and another of our heuristics (RAR) were by far the best.

Matthew G. Culver

2006-01-01T23:59:59.000Z

162

Thermal fatigue due to beam interruptions for an ALMR-type ATW  

SciTech Connect

Accelerator-driven subcritical reactors have been proposed for tasks such as accelerator transmutation of waste (ATW). In such a device, long-lived radioactive fission products and transuranic elements from spent fuel would be converted into short-lived radioactive isotopes and stable isotopes. One concern about such devices is that current proton accelerators typically experience beam interruptions many times per day. The beam interruptions last from seconds to hours. A beam interruption leads to a temperature transient similar to, but faster than, that from a reactor scram. These temperature transients cause thermal fatigue that can eventually lead to structural failures in various reactor components. The objective of the work reported here was to determine the design implications of this thermal fatigue.

Dunn, F.E.

2000-07-01T23:59:59.000Z

163

Neutron cross sections: Book of curves  

Science Conference Proceedings (OSTI)

Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross sections have been included. 11 refs., 4 figs.

McLane, V.; Dunford, C.L.; Rose, P.F.

1988-01-01T23:59:59.000Z

164

A Discrete Gust Model for Use in the Design of Wind Energy Conversion Systems  

Science Conference Proceedings (OSTI)

Discrete gust models, although idealizations of actual atmospheric conditions, are useful for engineering design. For fatigue design, these models must be representative of the conditions a structure or vehicle will experience on a continuous ...

Walter Frost; Robert E. Turner

1982-06-01T23:59:59.000Z

165

Dynamic muscle fatigue detection using self-organizing maps  

Science Conference Proceedings (OSTI)

Wavelets are used for the processing of signals that are non-stationary and time varying. The electromyogram (EMG) contains transient signals related to muscle activity. Wavelet coefficients are proposed as features for identifying muscle fatigue. By ... Keywords: Biomedical signal processing, Comfort, EMG, Muscle fatigue, Neural networks, Self-organizing maps, Transient signal, Visualization, Wavelets

Dimitrios Moshou; Ivo Hostens; George Papaioannou; Herman Ramon

2005-07-01T23:59:59.000Z

166

Conductor fatigue-life research. Final report  

Science Conference Proceedings (OSTI)

This is the final report of Research Project RP 1278-1 sponsored by the Electric Power Research Institute and carried out at the Civil Engineering Department of Auburn University (Auburn, Alabama). The objective of this study was to evaluate the effects of reducing vibration amplitudes of ACSR conductors which had been minimally damaged by aeolian vibration. The aeolian vibration was simulated by mechanical means in a controlled laboratory situation and the reduction in vibration amplitudes was a simulation of the addition of amplitude limiting devices (dampers). Conductors were vibrated at high amplitudes until a predetermined number of strand breaks occurred, after which the vibration was continued at reduced amplitudes. Three different ACSB conductors were tested: 795 KCM 26/7, 795 KCM 45/7, and 397.5 KCM 26/7. These conductors were chosen to establish the effects of conductor size and stranding on the amplitude reduction tests. Two different amplitude reductions were used to establish a threshold value for a maximum reduced amplitude. Previous preliminary research by others indicated that amplitude reductions extended the working life of conductors. This research expanded the amplitude reduction values and conductor sizes and strandings tested. For each set of parameters, four duplicative tests were performed to give statistical credence to the data. The results of the investigation indicated that amplitude reductions arrested fatigue strand breakage in each case. Electric utilities can utilize the results of this EPRI project in assessing the fatigue life of minimally damaged transmisson lines and in evaluating techniques for mitigating fatigue damage.

Ramey, G.E.

1981-07-01T23:59:59.000Z

167

Position paper: Seismic design criteria  

SciTech Connect

The purpose of this paper is to document the seismic design criteria to be used on the Title 11 design of the underground double-shell waste storage tanks and appurtenant facilities of the Multi-Function Waste Tank Facility (MWTF) project, and to provide the history and methodologies for determining the recommended Design Basis Earthquake (DBE) Peak Ground Acceleration (PGA) anchors for site-specific seismic response spectra curves. Response spectra curves for use in design are provided in Appendix A.

Farnworth, S.K.

1995-05-22T23:59:59.000Z

168

Design Optimisation Of An Offshore Wind Energy Converter By Means Of Tailored Dynamics  

E-Print Network (OSTI)

Tailoring the dynamics of an offshore wind energy converter can offer an effective design optimisation during the successive stages of the design process. Concerning the particular problem of fatigue due to combined wind and wave loading two simplified approaches are proposed and demonstrated which are well suited for the early design stages when integrated, non-linear time domain simulations are too cumbersome. This enables the use of standard design tools from the wind energy and offshore technology communities by superposition of separate analyses of hydrodynamic fatigue in the frequency domain and aerodynamic fatigue in the time domain.

M. Kühn

1999-01-01T23:59:59.000Z

169

Updated U.S. Geothermal Supply Curve  

Science Conference Proceedings (OSTI)

This paper documents the approach used to update the U.S. geothermal supply curve. The analysis undertaken in this study estimates the supply of electricity generation potential from geothermal resources in the United States and the levelized cost of electricity (LCOE), capital costs, and operating and maintenance costs associated with developing these geothermal resources. Supply curves were developed for four categories of geothermal resources: identified hydrothermal (6.4 GWe), undiscovered hydrothermal (30.0 GWe), near-hydrothermal field enhanced geothermal systems (EGS) (7.0 GWe) and deep EGS (15,900 GWe). Two cases were considered: a base case and a target case. Supply curves were generated for each of the four geothermal resource categories for both cases. For both cases, hydrothermal resources dominate the lower cost range of the combined geothermal supply curve. The supply curves indicate that the reservoir performance improvements assumed in the target case could significantly lower EGS costs and greatly increase EGS deployment over the base case.

Augustine, C.; Young, K. R.; Anderson, A.

2010-02-01T23:59:59.000Z

170

Fatigue Crack Closure and Corrosion Fatigue in Al 7075 Alloy Using ...  

Science Conference Proceedings (OSTI)

Traditional methods to quantify crack closure load, such as load-displacement curves, are not very accurate. In this study, the degree of crack closure through ...

171

Residential equipment part load curves for use in DOE-2  

SciTech Connect

DOE-2 (DOE2 90) includes several correlation curves that predict the energy use of systems underpart load conditions. DOE-2 simulates systems on an hour-by-hour basis, so the correlations are intended to predict part load energy use (and efficiency) as a function of the part load ratio (PLR) for each hour, where PLR = Hourly Load/Available Capacity. Generally residential and small commercial HVAC equipment meets the load at off-design conditions by cycling on and off. Therefore, the part load correlations must predict the degradation due to this on and off operation over an hourly interval.

Henderson, Hugh; Huang, Y.J.; Parker, D.

1999-02-01T23:59:59.000Z

172

Multi-Agent Model for Fatigue Control in Large Offshore Wind Farm  

Science Conference Proceedings (OSTI)

To control wind turbine fatigue and optimize the fatigue distribution for offshore wind farm, a control network model is proposed based on Multi-Agent theory. A typical model of large-scale offshore wind farm is described. Power fatigue of individual ... Keywords: Multi-Agent model, fatigue, wind turbine, offshore wind farm

Rongyong Zhao; Yongqing Su; Torben Knudsen; Thomas Bak; WenZhong Shen

2008-12-01T23:59:59.000Z

173

Fatigue Testing of 9 m Carbon Fiber Wind Turbine Research Blades  

SciTech Connect

Fatigue testing was conducted on Carbon Experimental and Twist-Bend Experimental (CX-100 and TX-100) 9-m wind turbine research blades. The CX-100 blade was designed to investigate the use of a carbon spar cap to reduce weight and increase stiffness while being incorporated using conventional manufacturing techniques. The TX-100 blade used carbon in the outboard portion of the skin to produce twist-bend coupling to passively alleviate aerodynamic loads. In the fatigue tests, the CX-100 blade was loaded by a single hydraulic cylinder while the TX-100 blade was loaded via a hydraulically-actuated resonant loading system called the Universal Resonant Exciter. The blades were outfitted with approximately 30 strain gages as well as displacement and load sensors. Both blades survived to cycle counts sufficient to demonstrate a 20-year operational life. The CX-100 blade failed at approximately 1.6 million cycles because of a buckle and crack that formed and grew just outboard of max-chord. The TX-100 blade failed because of a crack that grew from the termination point of the spar cap at the midspan of the blade. This paper covers the results of the fatigue tests.

Paquette, J.; van Dam, J.; Hughes, S.; Johnson, J.

2008-01-01T23:59:59.000Z

174

BOOK: Atlas of Stress-Strain Curves, 2nd Edition  

Science Conference Proceedings (OSTI)

Feb 9, 2007 ... The second edition of this publication contains more than 1400 curves, almost three times as many as in the 1987 edition.The curves are ...

175

Does the Environmental Kuznets Curve Describe How Individual Countries Behave?  

E-Print Network (OSTI)

the Environmental Kuznets Curve Does Not Exist,” AustralianDoes the Environmental Kuznets Curve Describe How Individualover time, even if it does not appear to do so immediately.

Deacon, Robert; Norman, Catherine S

2004-01-01T23:59:59.000Z

176

What ROC curves can’t do (and cost curves can  

E-Print Network (OSTI)

Abstract. This paper shows that ROC curves, as a method of visualizing classifier performance, are inadequate for the needs of Artificial Intelligence researchers in several significant respects, and demonstrates that a different way of visualizing performance – the cost curves introduced by Drummond and Holte at KDD’2000 – overcomes these deficiencies. 1

Chris Drummond; Robert C. Holte

2004-01-01T23:59:59.000Z

177

Ductile-reinforcement toughening in [gamma]-TiAl intermetallic-matrix composites: Effects on fracture toughness and fatigue-crack propagation resistance  

Science Conference Proceedings (OSTI)

The influence of the type, volume fraction, thickness and orientation of ductile phase reinforcements on the room temperature fatigue and fracture resistance of [gamma]-TiAl intermetallic alloys is investigated. Large improvements in toughness compared to monolithic [gamma]-TiAl are observed in both the TiNb- and Nb-reinforced composites under monotonic loading. Toughness increases with increasing ductile phase content, reinforcement thickness and strength; orientation effect are minimal. Crack-growth behavior is characterized by steep resistance curves primarily due to crack trapping/renucleation and extensive crack bridging by the ductile-phase particles. In contrast, under cyclic loading the influence of ductile phases on fatigue resistance is strongly dependent upon reinforcement orientation. Compared to monolithic [gamma]-TiAl, improvements in fatigue-crack growth resistance are observed in TiNb-reinforced composites only in the face (C-L) orientation; crack-growth rates for the edge (C-R) orientation are actually faster in the composite. In comparison, Nb-particle reinforcements offer less toughening under monotonic loading but enhance the fatigue properties compared to TiNb reinforcements under cyclic loading.

Venkateswara Rao, K.T.; Ritchie, R.O. (Univ. of California, Berkeley (United States). Dept. of Materials Science and Mineral Engineering); Odette, G.R. (Univ. of California, Santa Barbara (United States). Materials Dept.)

1994-03-01T23:59:59.000Z

178

Compactness of the space of causal curves  

E-Print Network (OSTI)

We prove that the space of causal curves between compact subsets of a separable globally hyperbolic poset is itself compact in the Vietoris topology. Although this result implies the usual result in general relativity, its proof does not require the use of geometry or differentiable structure.

Keye Martin

2004-08-19T23:59:59.000Z

179

Biomimetic soft lithography on curved nanostructured surfaces  

Science Conference Proceedings (OSTI)

In this paper a nano-molding process using a nature-created master is demonstrated. The eye of night moth Agotis exclamationis having 100nm-scale structures on a curved surface is used as biomimetic master mold from which nanostructures are replicated ... Keywords: Antireflective, Biomimetic, Nanostructures, Replication, Soft lithography

V. Auzelyte; V. Flauraud; V. J. Cadarso; T. Kiefer; J. Brugger

2012-09-01T23:59:59.000Z

180

Fractionalization of Interstitials in Curved Colloidal Crystals  

E-Print Network (OSTI)

Understanding the out-of equilibrium behaviour of point defects in crystals, yields insights into the nature and fragility of the ordered state, as well as being of great practical importance. In some rare cases defects are spontaneously healed - a one-dimensional crystal formed by a line of identical charged particles, for example, can accommodate an interstitial (extra particle) by a re-adjusting all particle positions to even out the spacing. In sharp contrast, particles organized into a perfect hexagonal crystal in the plane cannot accommodate an interstitial by a simple re-adjustment of the particle spacing - the interstitial remains instead trapped between lattice sites and diffuses by hopping, leaving the crystal permanently defected. Here we report on the behavior of interstitials in colloidal crystals on curved surfaces. Using optical tweezers operated independently of three dimensional imaging, we insert a colloidal interstitial in a lattice of similar particles on flat and curved (positively and negatively) oil-glycerol interfaces and image the ensuing dynamics. We find that, unlike in flat space, the curved crystals self-heal through a collective rearrangement that re-distributes the increased density associated with the interstitial. The self-healing process can be interpreted in terms of an out of equilibrium interaction of topological defects with each other and with the underlying curvature. Our observations suggest the existence of "particle fractionalization" on curved surface crystals.

William T. M. Irvine; Mark J. Bowick; Paul M. Chaikin

2013-10-11T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Updated Hubbert curves analyze world oil supply  

SciTech Connect

The question is not whether, but when, world crude oil production will start to decline, ushering in the permanent oil shock era. While global information for predicting this event is not so straightforward as the data M. King Hubbert used in creating his famous Hubbert Curve that predicted the US (Lower 48 states, or US/48) 1970 oil production peak, there are strong indications that most of the world`s large exploration targets have now been found. Meanwhile, the earth`s population is exploding along with the oil needs of Asia`s developing nations. This article reviews Hubbert`s original analyses on oil discovery and production curves for the US/48 and projects his proven methodology onto global oil discoveries and production as of 1992. The world`s oil discovery curve peaked in 1962, and thence declined, as a Hubbert Curve predicts. However, global production was restricted after the 1973 Arab oil embargo. Otherwise, world production would have peaked in the mid-1990s. Two graphs show alternate versions of future global oil production.

Ivanhoe, L.F. [Novum Corp., Ojai, CA (United States)

1996-11-01T23:59:59.000Z

182

Fatigue and failure responses of lead zirconate titanate multilayer actuator under unipolar high-field electric cycling  

Science Conference Proceedings (OSTI)

Lead zirconate titanate (PZT) multilayer actuators with an interdigital electrode design were studied under high electric fields (3 and 6 kV/mm) in a unipolar cycling mode. A 100 Hz sine wave was used in cycling. Five specimens tested under 6 kV/mm failed from 3.8 10^5 to 7 10^5 cycles, whereas three other specimens tested under 3 kV/mm were found to be still functional after 10^8 cycles. Variations in piezoelectric and dielectric responses of the tested specimens were observed during the fatigue test, depending on the measuring and cycling conditions. Selected fatigued and damaged actuators were characterized using an impedance analyzer or small signal measurement. A scanning acoustic microscope also was employed as a nondestructive tool to detect the presence of defects. Failed plates were subsequently sectioned, and the extensive cracks and porous regions were observed to be across the PZT layers. The results from this study have demonstrated that the high-field cycling can accelerate the fatigue of PZT stacks as long as the partial discharge is controlled. The small signal measurement can also be integrated into the large signal measurement to characterize the fatigue response of PZT stacks in a more comprehensive basis. The former can further serve as an experimental method to monitor the behavior of PZT stacks.

Zeng, Fan W [ORNL; Wang, Hong [ORNL; Lin, Hua-Tay [ORNL

2013-01-01T23:59:59.000Z

183

Unification of methods for determining distillation curve of oils  

Science Conference Proceedings (OSTI)

For the determination of the distillation curve of oils, various types of flask are recommended by industry-branch standards (OST) and specifications (TU). For example, TU 6-02-1072-86 for PEF fluid and TU 6-02-921-74 for the chlorofluorocarbon oil UF specify a Claisen flask (GOST 25336-82); the standard OST 38.01402-86 for mineral-base vacuum oils specifies a specially designed flask; TU 6-01-26-54-85 for Alkarene type vacuum oils specifies a Bogdanov flask. The latter two flasks are not included in any State (GOST) standards for chemical laboratory ware and hence are not in regular production. The accuracy in determining the distillation curve depends on the separating ability of the flask. Flasks designed as shown do not allow return of part of the condensate to the still section, so that it is impossible to regulate the reflux rate and hence impossible to obtain any reliable data on the fractional composition of the product and the distillation temperature. The Claisen and Bogdanov flasks, which have a developed surface, are more suitable for fractionation of oils.

Khitrik, A.A.; Vagapova, N.Kh.; Shagiakhmetov, R.A.

1994-09-01T23:59:59.000Z

184

Accelerated Fatigue Crack Growth Behavior of PWA 1480 Single ...  

Science Conference Proceedings (OSTI)

3 456. 610. 1520 30. AK . AKrss. MPa v'?! Fig. 10 Fatigue crack growth rate as a function of AKrss and AK. Prediction of the Microscopic Crack Behavior: An ...

185

Effect of Heat Treatment on Fatigue Behavior and Mechanical ...  

Science Conference Proceedings (OSTI)

The effect of heat treatment on the rotating beam fatigue strength of .... E9: Effect of Shot Peening on Bending Strength of AZ31 Magnesium Alloy Pipe · Effect of ...

186

Grain size effects on the fatigue response of nanocrystalline materials  

E-Print Network (OSTI)

The resistance of metals and alloys to fatigue crack initiation and propagation is known to be influenced significantly by grain size. Based on a wealth of experimental results obtained from microcrystalline metals, where ...

Hanlon, Timothy, 1977-

2004-01-01T23:59:59.000Z

187

Corrosion Fatigue Crack Growth and Stress-Corrosion Cracking in ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The high stress ratio (R=0.85) corrosion fatigue crack growth kinetics and stress-corrosion cracking resistance of sensitized (70-175 °C up to ...

188

Vibration Fatigue of Small Bore Socket-Welded Pipe Joints  

Science Conference Proceedings (OSTI)

In the course of developing the screening process for the EPRI Fatigue Management Handbook, TR-104534, several areas were identified in which the industry's understanding of socket welds was somewhat lacking and current ASME Code procedures were inadequate to accurately characterize their high-cycle fatigue resistance. The research described in this report is directed at improving the understanding of socket welds and the factors and parameters that affect a socket weld's ability to resist vibration-indu...

1997-06-27T23:59:59.000Z

189

Millville Wind Turbine Generator: failure analysis and corrective design modification  

DOE Green Energy (OSTI)

Fatigue cracks in the blade skins of the Millville Wind Turbine Generator were fractographically analyzed. It is believed they were caused by large flapwise deflections during a wind storm on December 4, 1978. The deflections caused the skin to buckle, which initiated rapidly growing fatigue cracks. Propagation continued to the leading edge, moving radially inward and outward along the leading edge radius. Communication between Rockwell and Millville resulted in a modified blade design which incorporates several corrective techniques.

Waldon, C.A.; Carr, M.J.; Grotzky, V.K.

1979-07-01T23:59:59.000Z

190

Tilting train smooths out the curves  

Science Conference Proceedings (OSTI)

This article describes a Swedish train that leans into curves and speed around them safely at more than 100 miles per hour and is being tested on a tortuous railroad corridor in the Northeast United States. If the test proves successful, the train--the X2000--could become a fixture in the country's rail system. The train has flexible steering that allows the wheels to hug the rail and permits it to drive around turns faster than most other trains, according to Amtrak. Further, all of the train, expect the locomotive, tilts as it winds its way around the curves. The tilting compensates for the centrifugal force on passengers at high speeds. The X2000 is one of several train systems under consideration by railroads in the United States to improve the rail system in the country. Among the others are Germany's Inter-City Express (ICE) and France's Train a Grande Vitesse (TGV), built by GEC Alshthom (Paris).

O'Connor, L.

1993-02-01T23:59:59.000Z

191

Quantum Mechanics and Closed Timelike Curves  

E-Print Network (OSTI)

General relativity allows solutions exhibiting closed timelike curves. Time travel generates paradoxes and quantum mechanics generalizations were proposed to solve those paradoxes. The implications of self-consistent interactions on acausal region of space-time are investigated. If the correspondence principle is true, then all generalizations of quantum mechanics on acausal manifolds are not renormalizable. Therefore quantum mechanics can only be defined on global hyperbolic manifolds and all general relativity solutions exhibiting time travel are unphysical.

Florin Moldoveanu

2007-04-23T23:59:59.000Z

192

Light Curves of Swift Gamma Ray Bursts  

E-Print Network (OSTI)

Recent observations from the Swift gamma-ray burst mission indicate that a fraction of gamma ray bursts are characterized by a canonical behaviour of the X-ray afterglows. We present an effective theory which allows us to account for X-ray light curves of both (short - long) gamma ray bursts and X-ray rich flashes. We propose that gamma ray bursts originate from massive magnetic powered pulsars.

Paolo Cea

2006-06-05T23:59:59.000Z

193

LIGHT CURVES OF SWIFT GAMMA RAY BURSTS  

E-Print Network (OSTI)

Recent observations from the Swift gamma-ray burst mission indicate that a fraction of gamma ray bursts are characterized by a canonical behaviour of the X-ray afterglows. We present an effective theory which allows us to account for X-ray light curves of both (short- long) gamma ray bursts and X-ray rich flashes. We propose that gamma ray bursts originate from massive magnetic powered pulsars. Subject headings: gamma-rays: bursts 1.

Paolo Cea

2006-01-01T23:59:59.000Z

194

Spectrum Fatigue Lifetime and Residual Strength for Fiberglass Laminates  

SciTech Connect

This report addresses the effects of spectrum loading on lifetime and residual strength of a typical fiberglass laminate configuration used in wind turbine blade construction. Over 1100 tests have been run on laboratory specimens under a variety of load sequences. Repeated block loading at two or more load levels, either tensile-tensile, compressive-compressive, or reversing, as well as more random standard spectra have been studied. Data have been obtained for residual strength at various stages of the lifetime. Several lifetime prediction theories have been applied to the results. The repeated block loading data show lifetimes that are usually shorter than predicted by the most widely used linear damage accumulation theory, Miner's sum. Actual lifetimes are in the range of 10 to 20 percent of predicted lifetime in many cases. Linear and nonlinear residual strength models tend to fit the data better than Miner's sum, with the nonlinear providing a better fit of the two. Direct tests of residual strength at various fractions of the lifetime are consistent with the residual strength models. Load sequencing effects are found to be insignificant. The more a spectrum deviates from constant amplitude, the more sensitive predictions are to the damage law used. The nonlinear model provided improved correlation with test data for a modified standard wind turbine spectrum. When a single, relatively high load cycle was removed, all models provided similar, though somewhat non-conservative correlation with the experimental results. Predictions for the full spectrum, including tensile and compressive loads were slightly non-conservative relative to the experimental data, and accurately captured the trend with varying maximum load. The nonlinear residual strength based prediction with a power law S-N curve extrapolation provided the best fit to the data in most cases. The selection of the constant amplitude fatigue regression model becomes important at the lower stress, higher cycle loading cases. The residual strength models may provide a more accurate estimate of blade lifetime than Miner's rule for some loads spectra. They have the added advantage of providing an estimate of current blade strength throughout the service life.

WAHL, NEIL K.; MANDELL, JOHN F.; SAMBORSKY, DANIEL D.

2002-03-01T23:59:59.000Z

195

Incorporating Experience Curves in Appliance Standards Analysis  

Science Conference Proceedings (OSTI)

The technical analyses in support of U.S. energy conservation standards for residential appliances and commercial equipment have typically assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. There is, however, considerable evidence that this assumption does not reflect real market prices. Costs and prices generally fall in relation to cumulative production, a phenomenon known as experience and modeled by a fairly robust empirical experience curve. Using price data from the Bureau of Labor Statistics, and shipment data obtained as part of the standards analysis process, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These allow us to develop more representative appliance price projections than the assumption-based approach of constant prices. These experience curves were incorporated into recent energy conservation standards for these products. The impact on the national modeling can be significant, often increasing the net present value of potential standard levels in the analysis. In some cases a previously cost-negative potential standard level demonstrates a benefit when incorporating experience. These results imply that past energy conservation standards analyses may have undervalued the economic benefits of potential standard levels.

Garbesi, Karina; Chan, Peter; Greenblatt, Jeffery; Kantner, Colleen; Lekov, Alex; Meyers, Stephen; Rosenquist, Gregory; Buskirk, Robert Van; Yang, Hung-Chia; Desroches, Louis-Benoit

2011-10-31T23:59:59.000Z

196

Late Light Curves of Normally-Luminous Type Ia Supernovae  

E-Print Network (OSTI)

The use of Type Ia supernovae as cosmological tools has reinforced the need to better understand these objects and their light curves. The light curves of Type Ia supernovae are powered by the nuclear decay of $^{56}Ni \\to ^{56}Co \\to ^{56}Fe$. The late time light curves can provide insight into the behavior of the decay products and their effect of the shape of the curves. We present the optical light curves of six "normal" Type Ia supernovae, obtained at late times with template image subtraction, and the fits of these light curves to supernova energy deposition models.

J. C. Lair; M. D. Leising; P. A. Milne; G. G. Williams

2006-01-05T23:59:59.000Z

197

Testing Controls to Mitigate Fatigue Loads in the Controls Advanced Research Turbine  

Science Conference Proceedings (OSTI)

Wind turbines are complex, nonlinear, dynamic systems forced by aerodynamic, gravitational, centrifugal, and gyroscopic loads. The aerodynamics of wind turbines is nonlinear, unsteady, and complex. Turbine rotors are subjected to a complicated three-dimensional (3D) turbulent wind inflow field with imbedded coherent vortices that drive fatigue loads and reduce lifetime. Design of control algorithms for wind turbines must account for multiple control objectives. Future large multi-megawatt turbines must be designed with lighter weight structures, using active controls to mitigate fatigue loads, maximize energy capture, and add active damping to maintain stability for these dynamically active structures operating in a complex environment. Researchers at the National Renewable Energy Laboratory are designing, implementing, and testing advanced controls to maximize energy extraction and reduce structural dynamic loads. These control designs are based on a linear model of the turbine that is generated by specialized modeling software. This paper describes testing of a control algorithm to mitigate blade, tower, and drivetrain loads using advanced state-space control methods. The controller uses independent blade pitch to regulate the turbine's speed in Region 3, mitigate the effects of shear across the rotor disk, and add active damping to the tower's first fore-aft bending mode. Additionally, a separate generator torque control loop is designed to add active damping to the tower's first side-side mode and the first drivetraintorsion mode. This paper discusses preliminary implementation and field tests of this controller in the Controls Advanced Research Turbine at the National Renewable Energy Laboratory. Also included are preliminary comparisons of the performance of this controller to results from a typical baseline Proportional-Integral-Derivative controller designed with just Region 3 speed regulation as the goal.

Wright, A. D.; Fingersh, L. J.; Stol, K. A.

2009-01-01T23:59:59.000Z

198

Design, prototyping and preliminary testing of an elastic-powered climbing exoskeleton  

E-Print Network (OSTI)

Human powered elastic mechanisms can be used to reduce work requirements of muscles, by storing and releasing energy to more evenly distribute work load. An exoskeleton was designed to delay human fatigue during rock ...

Briner, Hazel (Hazel Linn)

2011-01-01T23:59:59.000Z

199

Mooring Design Using Wave-State Estimate from the Southern Ocean  

Science Conference Proceedings (OSTI)

The Southern Ocean Flux Station was deployed near 47°S, 140°E. The extreme wind and wave conditions at this location require appropriate mooring design, which includes dynamic fatigue analysis and static analysis. An accurate estimate of the wave ...

E. W. Schulz; M. A. Grosenbaugh; L. Pender; D. J. M. Greenslade; T. W. Trull

2011-10-01T23:59:59.000Z

200

Factors Influencing Community Health Centers' Efficiency: A Latent Growth Curve Modeling Approach  

Science Conference Proceedings (OSTI)

The objective of study is to examine factors affecting the variation in technical and cost efficiency of community health centers (CHCs). A panel study design was formulated to examine the relationships among the contextual, organizational structural, ... Keywords: Community health centers, Cost efficiency, Growth curve modeling, Technical efficiency

Shriram Marathe; Thomas T. Wan; Jackie Zhang; Kevin Sherin

2007-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Parametric System Curves: Correlations Between Fan Pressure Rise and Flow for Large Commercial Buildings  

SciTech Connect

A substantial fraction of HVAC energy use in large commercial buildings is due to fan operation. Fan energy use depends in part on the relationship between system pressure drop and flow through the fan, which is commonly called a "system curve." As a step toward enabling better selections of air-handling system components and analyses of common energy efficiency measures such as duct static pressure reset and duct leakage sealing, this paper shows that a simple four-parameter physical model can be used to define system curves. Our model depends on the square of the fan flow, as is commonly considered. It also includes terms that account for linear-like flow resistances such as filters and coils, and for supply duct leakage when damper positions are fixed or are changed independently of static pressure or fan flow. Only two parameters are needed for systems with variable-position supply dampers (e.g., VAV box dampers modulating to control flow). For these systems, reducing or eliminating supply duct leakage does not change the system curve. The parametric system curve may be most useful when applied to field data. Non-linear techniques could be used to fit the curve to fan pressure rise and flow measurements over a range of operating conditions. During design, when measurements are unavailable, one could use duct design calculation tools instead to determine the coefficients.

Sherman, Max; Wray, Craig

2010-05-19T23:59:59.000Z

202

Experience curves for power plant emission control technologies  

E-Print Network (OSTI)

1/2, 2004 Experience curves for power plant emission controlcoal-fired electric power plants. In particular, we focus on2004) ‘Experience curves for power plant emission control

Rubin, Edward S.; Yeh, Sonia; Hounshell, David A; Taylor, Margaret R

2007-01-01T23:59:59.000Z

203

Probabilistic lane estimation for autonomous driving using basis curves  

E-Print Network (OSTI)

Lane estimation for autonomous driving can be formulated as a curve estimation problem, where local sensor data provides partial and noisy observations of spatial curves forming lane boundaries. The number of lanes to ...

Huang, Albert S.

204

Discrete Variational Calculus for B-spline Approximated Curves  

E-Print Network (OSTI)

We study variational problems for curves approximated by B-spline curves. We show that, one can obtain discrete Euler-Lagrange equations, for the data describing the approximated curves. Our main application is to the curve completion problem in 2D and 3D. In this case, the aim is to find various aesthetically pleasing solutions as opposed to a solution of a physical problem. The Lagrangians of interest are invariant under the special Euclidean group action for which B-spline approximated curves are well suited. Smooth Lagrangians with special Euclidean symmetries involve curvature, torsion, and arc length. Expressions in these, in the original coordinates, are highly complex. We show that, by contrast, relatively simple discrete Lagrangians offer excellent results for the curve completion problem. The methods we develop for the discrete curve completion problem are general and can be used to solve other discrete variational problems for B-spline curves.

Zhao, Jun

2010-01-01T23:59:59.000Z

205

Trajectory generationinhigh-speed,high-precisionmicromillingusing subdivision curves  

E-Print Network (OSTI)

uni- form, rational, b-spline (NURBS) curves. It is criticalCNC tool path in terms of B-spline curves, Computer-AidedClark, Recursively generated b-spline surface on arbitrary

Vijayaraghavan, Athulan; Sodemann, Angela; Hoover, Aaron; Mayor, J.Rhett; Dornfeld, David

2009-01-01T23:59:59.000Z

206

Simulator evaluation of manually flown curved instrument approaches  

E-Print Network (OSTI)

Pilot performance in flying horizontally curved instrument approaches was analyzed by having nine test subjects fly curved approaches in a fixed-base simulator. Approaches were flown without an autopilot and without a ...

Sager, Dennis Wayne

1973-01-01T23:59:59.000Z

207

R-curve behavior in ferrite ceramics  

SciTech Connect

The unusual dependence of the fracture mode of ferrite ceramics on the stress intensity factor in the subcritical crack growth regime was used to create flaws with different concentrations of crack-interface bridges. Flaws with numerous bridges were produced by indenting under dry silicone oil, while flaws with essentially no bridges were produced by indenting under water. Plots of log failure stress as a function of log indenter load for the two types of flaws reflect the differences in bridging. Those with extensive bridging showed pronounced R-curve behavior. The curve for those initially devoid of bridges showed no plateau but did show deviations from a {minus}1/3 slope that correspond to those predicted by Bennison and Lawn for this type of flaw. The ferrite studies was 62.4 Fe{sub 2}O{sub 3} 26.6 MnO, 11.2nO, and .04 V{sub 2}O{sub 5}. 10 figs.

Beauchamp, E.K.; Monroe, S.L.

1990-01-01T23:59:59.000Z

208

High speed curved position sensitive detector  

DOE Patents (OSTI)

A high speed curved position sensitive porportional counter detector for use in x-ray diffraction, the detection of 5-20 keV photons and the like. The detector employs a planar anode assembly of a plurality of parallel metallic wires. This anode assembly is supported between two cathode planes, with at least one of these cathode planes having a serpentine resistive path in the form of a meander having legs generally perpendicular to the anode wires. This meander is produced by special microelectronic fabrication techniques whereby the meander "wire" fans outwardly at the cathode ends to produce the curved aspect of the detector, and the legs of the meander are small in cross-section and very closely spaced whereby a spatial resolution of about 50 .mu.m can be achieved. All of the other performance characteristics are about as good or better than conventional position sensitive proportional counter type detectors. Count rates of up to 40,000 counts per second with 0.5 .mu.s shaping time constants are achieved.

Hendricks, Robert W. (Montgomery County, VA); Wilson, Jack W. (Knox County, TN)

1989-01-01T23:59:59.000Z

209

Environmentally Assisted Fatigue Gap Analysis and Roadmap for Future Research: Gap Analysis Report  

Science Conference Proceedings (OSTI)

Over the past two decades, there has been growing recognition of the effects of light water reactor (LWR) environments on fatigue initiation life and fatigue crack growth in nuclear power plant components, and environmentally assisted fatigue (EAF) has emerged as a significant issue affecting assessments to justify component lifetimes. Generally speaking, revised assessments are likely to predict reduced fatigue life and enhanced crack growth rates, as compared to corresponding predictions ...

2011-12-23T23:59:59.000Z

210

Materials Reliability Program: Thermal Fatigue Monitoring Guidelines (MRP-32, Revision 1)  

Science Conference Proceedings (OSTI)

This report provides thermal fatigue monitoring guidelines for attached piping systems in which there might be high potential for thermal fatigue cracking. The Materials Reliability Program (MRP) has published guidance under the Nuclear Energy Institute (NEI) 03-08 materials initiative for addressing potential thermal fatigue cycling in non-isolable reactor coolant system branch lines. This guidance calls for monitoring, inspection, and/or fatigue analysis of susceptible lines.

2011-06-16T23:59:59.000Z

211

Materials Reliability Program: Lessons Learned from PWR Thermal Fatigue Management Training (MRP-83)  

Science Conference Proceedings (OSTI)

In January 2001, The EPRI Materials Reliability Program (MRP) issued an Interim Guideline (MRP-24) for the management of thermal fatigue in non-isolable piping attached to reactor coolant piping in pressurized water reactor (PWR) plants (EPRI report 1000701). To assist utility personnel in understanding the potential for thermal fatigue in this piping, the MRP also conducted plant-specific workshops at plant sites. These workshops offered training on fatigue and fatigue cracking in non-isolable piping, a...

2002-12-05T23:59:59.000Z

212

Measured performances of curved inverted-vee, absorber compound parabolic concentrating solar-energy collectors  

SciTech Connect

The design and thermal performance of modified compound parabolic concentrating (CPC) solar-energy collectors are described. The designs incorporate a curved inverted-Vee absorber fin, which allows a reflector of simple geometry to be used. This CPC collector, has exhibited a superior performance to that of a conventional cusp-reflector CPC design, owing to the enhancement of the optical efficiency obtained by eliminating gap optical losses and an enhanced heat removal factor. The consequence upon the performance of a further design refinement, which inhibited the convective heat losses, is also reported.

Norton, B. (Univ. of Ulster at Jordanstown (Ireland)); Prapas, D.E. (Aristotle Univ. of Thessaloniki (Greece)); Eames, P.C.; Probert, S.D. (Cranfield Institute of Technology, Bedford (England))

1989-01-01T23:59:59.000Z

213

Reconstruction of quasi developable surfaces from ribbon curves  

Science Conference Proceedings (OSTI)

This paper deals with the acquisition and reconstruction of physical surfaces by mean of a ribbon device equipped with micro-sensors, providing geodesic curves running on the surface. The whole process involves the reconstruction of these 3D ribbon curves ... Keywords: Capture and reconstruction of surfaces, Coons filling methods, Developable and quasi developable surfaces, Geodesic curve, Hermite interpolation

Mathieu Huard; Nathalie Sprynski; Nicolas Szafran; Luc Biard

2013-07-01T23:59:59.000Z

214

Oil production models with normal rate curves Dudley Stark  

E-Print Network (OSTI)

Oil production models with normal rate curves Dudley Stark School of Mathematical Sciences Queen;Abstract The normal curve has been used to fit the rate of both world and U.S.A. oil production. In this paper we give the first theoretical basis for these curve fittings. It is well known that oil field

Stark, Dudley

215

Efficient pairing computation on Elliptic curves in Hessian form  

Science Conference Proceedings (OSTI)

Pairings in elliptic curve cryptography are functions which map a pair of elliptic curve points to a non-zero element of a finite field. In recent years, many useful cryptographic protocols based on pairings have been proposed. The fast implementations ... Keywords: Elliptic curve, Hessian form, tate paring

Haihua Gu; Dawu Gu; WenLu Xie

2010-12-01T23:59:59.000Z

216

Cost curves: An improved method for visualizing classifier performance  

Science Conference Proceedings (OSTI)

This paper introduces cost curves, a graphical technique for visualizing the performance (error rate or expected cost) of 2-class classifiers over the full range of possible class distributions and misclassification costs. Cost curves are shown to be ... Keywords: Classifiers, Machine learning, Performance evaluation, ROC curves

Chris Drummond; Robert C. Holte

2006-10-01T23:59:59.000Z

217

Classification and forecasting of load curves Nolwen Huet  

E-Print Network (OSTI)

on up to stabilisation of the clusters. Finally, the load profiles are predicted by covariance analysis of electricity customer uses. This load curve is only available for customers with automated meter readingClassification and forecasting of load curves Nolwen Huet Abstract The load curve, which gives

Cuesta, Juan Antonio

218

The Severi problem for rational curves on del Pezzo surfaces  

E-Print Network (OSTI)

Let X be a smooth projective surface and choose a curve C on X. Let VC be the set of all irreducible divisors on X linearly equivalent to C whose normalization is a rational curve. The Severi problem for rational curves ...

Testa, Damiano

2005-01-01T23:59:59.000Z

219

Fatigue case study and loading spectra for wind turbines  

DOE Green Energy (OSTI)

The paper discusses two aspects of Sandia`s Wind Energy Program. The first section of the paper presents a case study of fatigue in wind turbines. This case study was prepared for the American Society of Testing Material`s (ASTM) Standard Technical Publication (STP) on fatigue education. Using the LIFE2 code, the student is lead through the process of cumulative damage summation for wind turbines and typical data are used to demonstrate the range of life estimates that will result from typical parameter variations. The second section summarizes the results from a workshop held by Sandia and the National Renewable Energy Laboratory (NREL) to discuss fatigue life prediction methodologies. This section summarizes the workshop discussions on the use of statistical modeling to deduce the shape and magnitude of the low-probability-of-occurrence, high-stress tail of the load distribution on a wind turbine during normal operation.

Sutherland, H.J.

1994-05-01T23:59:59.000Z

220

A General Method for Fatigue Analysis of Vertical Axis  

E-Print Network (OSTI)

The fatigue life of wind turbine blades that are exposed to the random loading environment of atmospheric winds is described with random data analysis procedures. The incident wind speed and the stresses caused by these winds are expressed in terms of probability density functions, while the fatigue life vs stress level relationship is treated deterministically. This approach uses a "damage density function" to express fatigue damage as a function of wind speed. By examining the constraints on the variables in the damage density expression, some generalizations of the wind turbine fatigue problem are obtained. The area under the damage density function is inversely related to total fatigue life. Therefore, an increase in fatigue life caused by restricted operation in certain wind regimes is readily visualized. An "on parameter", which is the percentage of total time at each wind speed that the turbine actually operates, is introduced for this purpose. An example calculation is presented using data acquired from the DOE 100-kW turbine program. *This work was performed at Sandia National Laboratories and was supported by the US Department of Energy under Contract Number DE-AC04-76DP00789. Acknowledgments The calculations required to produce the figures in this paper would not have been possible without the work of Jerry McNerney and Tim Leonard in developing the AUTOSYM computer simulation, The efforts of Nolan Clark and Ron Davis in collecting data for the DOE 100-kW turbine at the USDA station in Bushland, TX are greatly appreciated. of Vertical Axis Wind Turbine Blades

Paul S. Veers

1983-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Updated U.S. Geothermal Supply Curve  

NLE Websites -- All DOE Office Websites (Extended Search)

CP-6A2-47458 CP-6A2-47458 February 2010 Updated U.S. Geothermal Supply Curve Chad Augustine and Katherine R. Young National Renewable Energy Laboratory Arlene Anderson U.S. Department of Energy Presented at Stanford Geothermal Workshop Stanford, California February 1, 2010 NOTICE The submitted manuscript has been offered by an employee of the Alliance for Sustainable Energy, LLC (ASE), a contractor of the US Government under Contract No. DE-AC36-08-GO28308. Accordingly, the US Government and ASE retain a nonexclusive royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for US Government purposes. This report was prepared as an account of work sponsored by an agency of the United States government.

222

Semilinear Hyperbolic Equations in Curved Spacetime  

E-Print Network (OSTI)

This is a survey of the author's recent work rather than a broad survey of the literature. The survey is concerned with the global in time solutions of the Cauchy problem for matter waves propagating in the curved spacetimes, which can be, in particular, modeled by cosmological models. We examine the global in time solutions of some class of semililear hyperbolic equations, such as the Klein-Gordon equation, which includes the Higgs boson equation in the Minkowski spacetime, de Sitter spacetime, and Einstein & de Sitter spacetime. The crucial tool for the obtaining those results is a new approach suggested by the author based on the integral transform with the kernel containing the hypergeometric function.\\\\ {\\bf Mathematics Subject Classification (2010):} Primary 35L71, 35L53; Secondary 81T20, 35C15.\\\\ {\\bf Keywords:} \\small {de Sitter spacetime; Klein-Gordon equation; Global solutions; Huygens' principle; Higuchi bound}

Karen Yagdjian

2013-05-19T23:59:59.000Z

223

Environmental management by the learning curve  

Science Conference Proceedings (OSTI)

This is a futuristic appreciation of waste management challenges and their solution by means of good management models. A literature review, administrative initiatives, research results, and experiences from practice are combined in this study to render an evolutionary picture of the change in paradigm relative to municipal solid waste possible to occur between 2000 and 2025. The principal stages of progress in the 25 years studied were: the correct characterization of municipal solid waste as a function of geographical location and recycling potential, the divided collection model and its corresponding learning curve, correct opportunity cost accounting tools, and the generally admitted and accepted changeover of municipal solid waste treatment from a technical to a management problem. It is reported that as a result of this progress, the municipal landfill is a species in extinction. Regional landfills with long life spans are the rule in 2025.

Fehr, M

2003-07-01T23:59:59.000Z

224

Modeling Thermal Fatigue in CPV Cell Assemblies: Preprint  

DOE Green Energy (OSTI)

A finite element model has been created to quantify the thermal fatigue damage of the CPV die attach. Simulations are used to compare to results of empirical thermal fatigue equations originally developed for accelerated chamber cycling. While the empirical equations show promise when extrapolated to the lower temperature cycles characteristic of weather-induced temperature changes in the CPV die attach, it is demonstrated that their damage does not accumulate linearly: the damage a particular cycle contributes depends on the preceding cycles. Simulations of modeled CPV cell temperature histories provided for direct comparison of the FEM and empirical methods, and for calculation of equivalent times provided by standard accelerated test sequences.

Bosco, N.; Silverman, T. J.; Kurtz, S.

2011-07-01T23:59:59.000Z

225

Mechanisms for fatigue and wear of polysilicon structural thinfilms  

Science Conference Proceedings (OSTI)

Fatigue and wear in micron-scale polysilicon structural films can severely impact the reliability of microelectromechanical systems (MEMS). Despite studies on fatigue and wear behavior of these films, there is still an on-going debate regarding the precise physical mechanisms for these two important failure modes. Although macro-scale silicon does not fatigue, this phenomenon is observed in micron-scale silicon. It is shown that for polysilicon devices fabricated in the MUMPs foundry and SUMMiT process stress-lifetime data exhibits similar trends in ambient air, shorter lifetimes in higher relative humidity environments and no fatigue failure at all in high vacuum. Transmission electron microscopy of the surface oxides of the samples show an approximate four-fold thickening of the oxide at stress concentrations after fatigue failure, but no thickening after fracture in air or after fatigue cycling in vacuo. It is found that such oxide thickening and fatigue failure (in air) occurs in devices with initial oxide thicknesses of {approx}4-20 nm. Such results are interpreted and explained by a reaction layer fatigue mechanism; specifically, moisture-assisted subcritical cracking within a cyclic stress-assisted thickened oxide layer occurs until the crack reaches a critical size to cause catastrophic failure. Polysilicon specimens from the SUMMiT process are used to study wear mechanisms in micron-scale silicon in ambient air. Worn parts are examined by analytical scanning and transmission electron microscopy, while temperature changes are monitored using infrared microscopy. These results are compared with the development of values of static coefficients of friction (COF) with number of wear cycles. Observations show amorphous debris particles ({approx}50-100 nm) created by fracture through the silicon grains ({approx}500 nm), which subsequently oxidize, agglomerate into clusters and create plowing tracks. A nano-crystalline layer ({approx}20-200 nm) forms at worn regions. No dislocations or extreme temperature increases are found, ruling out plasticity and temperature-assisted mechanisms. The COF reaches a steady-state value of {approx}0.20{+-}0.05 after a short time at an initial value of {approx}0.11{+-}0.01. Plowing tracks are found before the steady-state value of the COF is reached, suggesting only a short adhesive wear regime. This suggests a predominantly abrasive wear mechanism, controlled by fracture, which commences by the first particles created by adhesive wear.

Alsem, Daniel Henricus

2006-12-01T23:59:59.000Z

226

Contributions to an Improved Oxygen and Thermal Transport Model and Development of Fatigue Analysis Software for Asphalt Pavements  

E-Print Network (OSTI)

Fatigue cracking is one primary distress in asphalt pavements, dominant especially in later years of service. Prediction of mixture fatigue resistance is critical for various applications, e.g., pavement design and preventative maintenance. The goal of this work was to develop a tool for prediction of binder aging level and mixture fatigue life in pavement from unaged binder/mixture properties. To fulfill this goal, binder oxidation during the early fast-rate period must be understood. In addition, a better hourly air temperature model is required to provide accurate input for the pavement temperature prediction model. Furthermore, a user-friendly software needs to be developed to incorporate these findings. Experiments were conducted to study the carbonyl group formation in one unmodified binder (SEM 64-22) and one polymer-modified binder (SEM 70-22), aged at five elevated temperatures. Data of SEM 64-22, especially at low temperatures, showed support for a parallel-reaction model, one first order reaction and one zero order reaction. The model did not fit data of SEM 70-22. The polymer modification of SEM 70-22 might be responsible for this discrepancy. Nonetheless, more data are required to draw a conclusion. Binder oxidation rate is highly temperature dependent. Hourly air temperature data are required as input for the pavement temperature prediction model. Herein a new pattern-based air temperature model was developed to estimate hourly data from daily data. The pattern is obtained from time series analysis of measured data. The new model yields consistently better results than the conventional sinusoidal model. The pavement aging and fatigue analysis (PAFA) software developed herein synthesizes new findings from this work and constant-rate binder oxidation and hardening kinetics and calibrated mechanistic approach with surface energy (CMSE) fatigue analysis algorithm from literature. Input data include reaction kinetics parameters, mixture test results, and pavement temperature. Carbonyl area growth, dynamic shear rheometer (DSR) function hardening, and mixture fatigue life decline are predicted as function of time. Results are plotted and saved in spreadsheets.

Jin, Xin

2009-08-01T23:59:59.000Z

227

Selected GHG Emission Supply Curves | Open Energy Information  

Open Energy Info (EERE)

Selected GHG Emission Supply Curves Selected GHG Emission Supply Curves Jump to: navigation, search Tool Summary Name: Selected GHG Emission Supply Curves Agency/Company /Organization: Northwest Power and Conservation Council Sector: Energy Focus Area: Conventional Energy, Energy Efficiency, Renewable Energy, Industry, Transportation, Forestry, Agriculture Topics: GHG inventory, Pathways analysis Resource Type: Dataset, Publications Website: www.nwcouncil.org/energy/grac/20090130_Supply%20Curves_NWPCC_FINAL.pdf Selected GHG Emission Supply Curves Screenshot References: Selected GHG Emission Supply Curves[1] Background "The ECL supply curve model includes data on potential emission reductions for approximately 60 separate technology options. It allows the examination of multiple scenarios involving the inclusion or exclusion of technology

228

Temperature dependence of the intrinsic small fatigue crack growth behavior in Ni-base superalloys based on measurement of crack closure  

Science Conference Proceedings (OSTI)

The effect of temperature on the small fatigue crack growth behavior of a single crystal and directionally solidified Ni-base superalloys was investigated at temperatures between 873 to 1,123 K by measuring the crack closure. The results were also compared with those of the physically long crack. It was found that the propagation resistance and the fatigue threshold of the long cracks increased with temperature in all the materials. The long crack growth rates at three temperatures were approximately represented by an unique curve, after taking account of crack closure level and elastic modulus. In contrast, the small crack growth resistance decreased with temperature even when the crack closure phenomenon was taken into consideration. Furthermore, the small fatigue cracks exhibited considerably higher growth rates than the long cracks at a given effective stress intensity factor range and also grew under effective stress intensity factor ranges below the long crack threshold. The factors responsible for the lack of similitude in propagation rates between small and long cracks were also discussed, based on these observations and the chemical analysis near the crack tip using the electron probe microanalyzer.

Okazaki, M.; Yamada, H. [Nagaoka Univ. of Technology (Japan). Dept. of Mechanical Engineering; Nohmi, S. [Kawasaki Heavy Industries Co. Ltd., Akashi (Japan)

1996-04-01T23:59:59.000Z

229

Damage tolerance design procedures for an automotive composite  

DOE Green Energy (OSTI)

Among the durability issues of concern in the use of composites in automobile structures is the damaging effects that low-energy impacts (e.g., tool drops and roadway kickups) might have on strength and stiffness. This issue was experimentally investigated, and recommended design evaluation procedures were developed for a candidate automotive structural composite--a structural reaction injection-molded polyurethane reinforced with continuous strand, swirl-mat E-glass fibers. Two test facilities were built to cover the range of impacts of interest--a pendulum device to characterize the effects of relative heavy objects at low velocities and an air gun to characterize the effects of relatively light objects at higher velocities. In all cases, the test specimen was a 9 x 9 x 1/8-in.-thick plate clamped on an 8-in.-diam circle. Sixty-five impact tests were performed. Included were tests using various impactor sizes and weights, tests at {minus}40 F, and tests on specimens that has been presoaked in water or exposed to battery acid. Damage areas were determined using ultrasonic C-scans, and the resulting areas were found to correlate with the quantity impactor mass to a power times velocity. A design curve was derived from the correlation and validated using dropped brick tests. To evaluate strength and stiffness reductions, the impacted plate specimens were cut into tensile, compressive, and fatigue test specimens that were used to determine reductions as a function of damage area. It was found that for design purposes, the strength reduction could be determined by representing the damage area by a circular hole of equivalent area.

Corum, J.M.; Battiste, R.L.

1998-11-01T23:59:59.000Z

230

D-Branes in Curved Space  

Science Conference Proceedings (OSTI)

This thesis is a study of D-branes in string compactifications. In this context, D-branes are relevant as an important component of the nonperturbative spectrum, as an incisive probe of these backgrounds, and as a natural stringy tool for localizing gauge interactions. In the first part of the thesis, we discuss half-BPS D-branes in compactifications of type II string theory on Calabi-Yau threefolds. The results we describe for these objects are pertinent both in their role as stringy brane-worlds, and in their role as solitonic objects. In particular, we determine couplings of these branes to the moduli determining the closed-string geometry, both perturbatively and non-perturbatively in the worldsheet expansion. We provide a local model for transitions in moduli space where the BPS spectrum jumps, and discuss the extension of mirror symmetry between Calabi-Yau manifolds to the case when D-branes are present. The next section is an interlude which provides some applications of D-branes to other curved backgrounds of string theory. In particular, we discuss a surprising phenomenon in which fundamental strings moving through background Ramond-Ramond fields dissolve into large spherical D3-branes. This mechanism is used to explain a previously-mysterious fact discovered via the AdS-CFT correspondence. Next, we make a connection between type IIA string vacua of the type discussed in the first section and M-theory compactifications on manifolds of G{sub 2} holonomy. Finally we discuss constructions of string vacua which do not have large radius limits. In the final part of the thesis, we develop techniques for studying the worldsheets of open strings ending on the curved D-branes studied in the first section. More precisely, we formulate a large class of massive two-dimensional gauge theories coupled to boundary matter, which flow in the infrared to the relevant boundary conformal field theories. Along with many other applications, these techniques are used to describe world-volume theories of point-like D-probes of various Calabi-Yau threefolds.

McGreevy, John Austen; /Stanford U., Phys. Dept.

2005-07-06T23:59:59.000Z

231

Probabilistic fatigue damage prognosis using maximum entropy approach  

E-Print Network (OSTI)

al., 1979). Therefore, fatigue damage accumulation is stochastic in nature. Several physical models, parameter estimation and future inspection and maintenance need to be carefully included for risk assessment studies have been reported to combine the information obtained from inspection with the physical model

Liu, Yongming

232

Fatigue-crack propagation behavior of Inconel 718  

DOE Green Energy (OSTI)

The techniques of linear-elastic fracture mechanics were used to characterize the effect of several variables (temperature, environment, cyclic frequency, stress ratio, and heat-treatment variations) upon the fatigue-crack growth behavior of Inconel 718 base metal and weldments. Relevant crack growth data on this alloy from other laboratories is also presented. (33 fig, 39 references) (auth)

James, L.A.

1975-09-01T23:59:59.000Z

233

Fatigue crack growth estimation by relevance vector machine  

Science Conference Proceedings (OSTI)

The investigation of damage propagation mechanisms on a selected safety-critical component or structure requires the quantification of its remaining useful life (RUL) to verify until when it can continue performing the required function. In this work, ... Keywords: Bayesian techniques, Fatigue crack growth, Prognostics, Relevance vector machine, Residual useful life, Support vector machine

Enrico Zio; Francesco Di Maio

2012-09-01T23:59:59.000Z

234

Reversible Bending Fatigue Test System for Investigating Vibration Integrity of Spent Nuclear Fuel during Transportation  

SciTech Connect

Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During transportation, SNF experiences unique conditions and challenges to cladding integrity due to the vibrational and impact loading during road or rail shipment. Oak Ridge National Laboratory (ORNL) has been developing testing capabilities that can be used to improve the understanding of the impacts on SNF integrity due to vibration loading, especially for high burn-up SNF in normal transportation operation conditions. This information can be used to meet the nuclear industry and U.S. Nuclear Regulatory Commission needs in the area of safety and security of spent nuclear fuel storage and transport operations. The ORNL developed test system can perform reversible-bending fatigue testing to evaluate both the static and dynamic mechanical response of SNF rods under simulated loads. The testing apparatus is also designed to meet the challenges of hot-cell operation, including remote installation and detachment of the SNF test specimen, in-situ test specimen deformation measurement, and implementation of a driving system suitable for use in a hot cell. The system contains a U-frame set-up equipped with uniquely designed grip rigs, to protect SNF rod and to ensure valid test results, and use of 3 specially designed LVDTs to obtain the in-situ curvature measurement. A variety of surrogate test rods have been used to develop and calibrate the test system as well as in performing a series of systematic cyclic fatigue tests. The surrogate rods include stainless steel (SS) cladding, SS cladding with cast epoxy, and SS cladding with alumina pellets inserts simulating fuel pellets. Testing to date has shown that the interface bonding between the SS cladding and the alumina pellets has a significant impact on the bending response of the test rods as well as their fatigue strength. The failure behaviors observed from tested surrogate rods provides a fundamental understanding of the underlying failure mechanisms of the SNF surrogate rod under vibration which has not been achieved previously. The newly developed device is scheduled to be installed in the hot-cell in summer 2013 to test high burnup SNF.

Wang, Jy-An John [ORNL; Wang, Hong [ORNL; Bevard, Bruce Balkcom [ORNL; Howard, Rob L [ORNL; Flanagan, Michelle [U.S. Nuclear Regulatory Commission

2013-01-01T23:59:59.000Z

235

Solar winds along curved magnetic field lines  

E-Print Network (OSTI)

Both remote-sensing measurements using the interplanetary scintillation (IPS) technique and in situ measurements by the Ulysses spacecraft show a bimodal structure for the solar wind at solar minimum conditions. At present what makes the fast wind fast and the slow wind slow still remains to be answered. While a robust empirical correlation exists between the coronal expansion rate $f_c$ of the flow tubes and the speeds $v$ measured in situ, further data analysis suggests that $v$ depends on more than just $f_c$. We examine whether the non-radial shape of field lines, which naturally accompanies any non-radial expansion, could be an additional geometrical factor. We solved the transport equations incorporating the heating due to turbulent Alfv\\'en waves for an electron-proton solar wind along curved field lines given by an analytical magnetic field model, representative of a solar minimum corona. The field line shape is found to influence substantially the solar wind parameters, reducing the asymptotic speed ...

Li, Bo; Chen, Yao

2011-01-01T23:59:59.000Z

236

NONPARAMETRIC BAYESIAN ESTIMATION OF PERIODIC LIGHT CURVES  

SciTech Connect

Many astronomical phenomena exhibit patterns that have periodic behavior. An important step when analyzing data from such processes is the problem of identifying the period: estimating the period of a periodic function based on noisy observations made at irregularly spaced time points. This problem is still a difficult challenge despite extensive study in different disciplines. This paper makes several contributions toward solving this problem. First, we present a nonparametric Bayesian model for period finding, based on Gaussian Processes (GPs), that does not make assumptions on the shape of the periodic function. As our experiments demonstrate, the new model leads to significantly better results in period estimation especially when the light curve does not exhibit sinusoidal shape. Second, we develop a new algorithm for parameter optimization for GP which is useful when the likelihood function is very sensitive to the parameters with numerous local minima, as in the case of period estimation. The algorithm combines gradient optimization with grid search and incorporates several mechanisms to overcome the high computational complexity of GP. Third, we develop a novel approach for using domain knowledge, in the form of a probabilistic generative model, and incorporate it into the period estimation algorithm. Experimental results validate our approach showing significant improvement over existing methods.

Wang Yuyang; Khardon, Roni [Department of Computer Science, Tufts University, Medford, MA (United States); Protopapas, Pavlos [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

2012-09-01T23:59:59.000Z

237

Fatigue Fracture Behavior of ARB Processed Aluminum  

Science Conference Proceedings (OSTI)

Design of Pre-Weakening and Evaluation of Structural Safety for Explosive ... Crystallization Temperature of Pd-Cu-Si System Using Integrated Thin Film Samples ... Mechanical Properties of 5083 Aluminium Welds after Manual and Automatic ...

238

ECN GHG Marginal Abatement Cost curves (NAMAC) | Open Energy Information  

Open Energy Info (EERE)

ECN GHG Marginal Abatement Cost curves (NAMAC) ECN GHG Marginal Abatement Cost curves (NAMAC) Jump to: navigation, search Tool Summary Name: ECN GHG Marginal Abatement Cost curves for the Non-Annex I region (NAMAC) Agency/Company /Organization: Energy Research Centre of the Netherlands Sector: Energy, Land Topics: Resource assessment, Pathways analysis, Background analysis Website: www.ecn.nl/docs/library/report/2006/e06060.pdf References: GHG Marginal Abatement Cost curves for the Non-Annex I region[1] GHG Marginal Abatement Cost curves for the Non-Annex I region (NAMAC) (1999-present) ECN has developed a Marginal Abatement Cost curve containing detailed information on mitigation technologies and abatement costs in developing countries. * The MAC was first developed for the Dutch Ministry of Foreign

239

Decline curve derivative analysis for homogeneous and composite reservoirs  

DOE Green Energy (OSTI)

In this study, the rate decline and rate decline derivatives of a constant pressure well are presented for infinite, constant pressure outer boundary, and closed outer boundary homogeneous reservoirs. A rate derivative type curve is provided for these cases as well. The effects of the dimensionless reservoir exterior radius are discussed. Rate decline and rate decline derivatives of a constant pressure well in an infinite composite reservoir are also presented. For composite reservoirs, the effects of mobility ratios and discontinuity distance on both rate decline and rate decline derivatives are presented. Type curves for dimensionless wellbore flow rate derivatives for infinite composite reservoirs are provided. A new correlating group for the derivative type curve is provided, and is different than the correlating group for the rate type curve presented in the past. Finally, an analysis method that comprises type curve and derivative type curve matching to determine the dimensionless variables is proposed and demonstrated with a simulated example.

Demski, J.A.

1987-06-01T23:59:59.000Z

240

Refinements and Tests of an Advanced Controller to Mitigate Fatigue Loads in the Controls Advanced Research Turbine: Preprint  

DOE Green Energy (OSTI)

Wind turbines are complex, nonlinear, dynamic systems forced by aerodynamic, gravitational, centrifugal, and gyroscopic loads. The aerodynamics of wind turbines are nonlinear, unsteady, and complex. Turbine rotors are subjected to a complicated 3-D turbulent wind inflow field, with imbedded coherent vortices that drive fatigue loads and reduce lifetime. Design of control algorithms for wind turbines must account for multiple control objectives. Future large multi-megawatt turbines must be designed with lighter weight structures, using active controls to mitigate fatigue loads, while maximizing energy capture. Active damping should be added to these dynamic structures to maintain stability for operation in a complex environment. At the National Renewable Energy Laboratory (NREL), we have designed, implemented, and tested advanced controls to maximize energy extraction and reduce structural dynamic loads. These control designs are based on linear models of the turbine that are generated by specialized modeling software. In this paper, we present field test results of an advanced control algorithm to mitigate blade, tower, and drivetrain loads in Region 3.

Wright, A.; Fleming, P.

2010-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Motor System Energy Efficiency Supply Curves: A Methodology for...  

NLE Websites -- All DOE Office Websites (Extended Search)

Motor System Energy Efficiency Supply Curves: A Methodology for Assessing the Energy Efficiency Potential of Industrial Motor Systems Speaker(s): Ali Hasanbeigi Date: February 8,...

242

A local fitting algorithm for converting planar curves to  

E-Print Network (OSTI)

In this paper we present a local fitting algorithm for converting smooth planar curves to B-splines. For a smooth planar curve a set of points together with their tangent vectors are first sampled from the curve such that the connected polygon approximates the curve with high accuracy and inflexions are detected by the sampled data efficiently. Then, a G 1 continuous Bézier spline curve is obtained by fitting the sampled data with shape preservation as well as within a prescribed accuracy. Finally, the Bézier spline is merged into a C 2 continuous B-spline curve by subdivision and control points adjustment. The merging is guaranteed to be within another error bound and with no more inflexions than the Bézier spline. In addition to shape preserving and error control, this conversion algorithm also benefits that the knots are selected automatically and adaptively according to local shape and error bound. A few experimental results are included to demonstrate the validity and efficiency of the algorithm. Keywords: curve conversion; B-spline curve; cubic Bézier curve; knot selection; shape preserving 1.

unknown authors

2007-01-01T23:59:59.000Z

243

Synthesis of Space-Filling Curves Through Measure- Preserving ...  

E-Print Network (OSTI)

by composing it with a space-filling curve (SFC), searches for a small group of candidates and ..... machine learning and maximum likelihood estimation.

244

Insulated pipe clamp design  

SciTech Connect

Thin wall large diameter piping for breeder reactor plants can be subjected to significant thermal shocks during reactor scrams and other upset events. On the Fast Flux Test Facility, the addition of thick clamps directly on the piping was undesired because the differential metal temperatures between the pipe wall and the clamp could have significantly reduced the pipe thermal fatigue life cycle capabilities. Accordingly, an insulated pipe clamp design concept was developed. The design considerations and methods along with the development tests are presented. Special considerations to guard against adverse cracking of the insulation material, to maintain the clamp-pipe stiffness desired during a seismic event, to minimize clamp restraint on the pipe during normal pipe heatup, and to resist clamp rotation or spinning on the pipe are emphasized.

Anderson, M.J.; Hyde, L.L.; Wagner, S.E.; Severud, L.K.

1980-01-01T23:59:59.000Z

245

Assessing Fatigue and Ultimate Load Uncertainty in Floating Offshore Wind Turbines Due to Varying Simulation Length  

SciTech Connect

With the push towards siting wind turbines farther offshore due to higher wind quality and less visibility, floating offshore wind turbines, which can be located in deep water, are becoming an economically attractive option. The International Electrotechnical Commission's (IEC) 61400-3 design standard covers fixed-bottom offshore wind turbines, but there are a number of new research questions that need to be answered to modify these standards so that they are applicable to floating wind turbines. One issue is the appropriate simulation length needed for floating turbines. This paper will discuss the results from a study assessing the impact of simulation length on the ultimate and fatigue loads of the structure, and will address uncertainties associated with changing the simulation length for the analyzed floating platform. Recommendations of required simulation length based on load uncertainty will be made and compared to current simulation length requirements.

Stewart, G.; Lackner, M.; Haid, L.; Matha, D.; Jonkman, J.; Robertson, A.

2013-07-01T23:59:59.000Z

246

Assessing Fatigue and Ultimate Load Uncertainty in Floating Offshore Wind Turbines Due to Varying Simulation Length  

DOE Green Energy (OSTI)

With the push towards siting wind turbines farther offshore due to higher wind quality and less visibility, floating offshore wind turbines, which can be located in deep water, are becoming an economically attractive option. The International Electrotechnical Commission's (IEC) 61400-3 design standard covers fixed-bottom offshore wind turbines, but there are a number of new research questions that need to be answered to modify these standards so that they are applicable to floating wind turbines. One issue is the appropriate simulation length needed for floating turbines. This paper will discuss the results from a study assessing the impact of simulation length on the ultimate and fatigue loads of the structure, and will address uncertainties associated with changing the simulation length for the analyzed floating platform. Recommendations of required simulation length based on load uncertainty will be made and compared to current simulation length requirements.

Stewart, G.; Lackner, M.; Haid, L.; Matha, D.; Jonkman, J.; Robertson, A.

2013-07-01T23:59:59.000Z

247

Method for Fatigue Pre-cracking of Pipeline Test Samples  

Science Conference Proceedings (OSTI)

... hydraulic mechanical test frame and cyclically loaded in 4 ... a function of the number of load cycles, coupled ... gage length of ~ 1 m) curved wide plate ...

2012-10-01T23:59:59.000Z

248

White Dwarf Light Curves: Constraining Convection and Mode Identification Using Non-sinusoidal Light Curves  

E-Print Network (OSTI)

In this paper we show how the formalism of Wu & Goldreich developed for weakly nonlinear white dwarf pulsations can be extended to the fully nonlinear case. Due to the computational simplification this affords over the simulations of Brickhill (1992) and Ising & Koester (2001), we are able to obtain the first ever fits of observed light curves. These fits allow us to obtain not only mode identifications but also to constrain the average depth of the convection zone and its sensitivity to changes in effective temperature. We are thus able to probe the fundamental physics of convection in these objects.

M. H. Montgomery

2004-11-14T23:59:59.000Z

249

Solving Elliptic Curve Discrete Logarithm Problems Using Weil Descent  

E-Print Network (OSTI)

We provide the first cryptographically interesting instance of the elliptic curve discrete logarithm problem which resists all previously known attacks, but which can be solved with modest computer resources using the Weil descent attack methodology of Frey. We report on our implementation of index-calculus methods for hyperelliptic curves over characteristic two finite fields, and discuss the cryptographic implications of our results.

Michael Jacobson; Alfred Menezes; Andreas Stein

2001-01-01T23:59:59.000Z

250

Modelling light curves of binary systems: accounting for extended winds  

E-Print Network (OSTI)

We suggest a simple synthesis model of an eclipsing binary system which includes one component with strong stellar wind. Numerical simulations show that the shape of the light curve (and in particularly the widths of the minima) strongly depends on wind parameters. Wind effects are crucial in modelling light curves of binaries including e.g., WR stars.

Antokhina, E A; Cherepashchuk, A M

2013-01-01T23:59:59.000Z

251

Dynamic tracking of page miss ratio curve for memory management  

Science Conference Proceedings (OSTI)

Memory can be efficiently utilized if the dynamic memory demands of applications can be determined and analyzed at run-time. The page miss ratio curve(MRC), i.e. page miss rate vs. memory size curve, is a good performance-directed metric to serve this ... Keywords: memory management, power management, resource allocation

Pin Zhou; Vivek Pandey; Jagadeesan Sundaresan; Anand Raghuraman; Yuanyuan Zhou; Sanjeev Kumar

2004-12-01T23:59:59.000Z

252

Computing the Fréchet distance between piecewise smooth curves  

Science Conference Proceedings (OSTI)

We consider the Frechet distance between two curves which are given as a sequence of m+n curved pieces. If these pieces are sufficiently well-behaved, we can compute the Frechet distance in O(mnlog(mn)) time. The decision version of the problem can be ... Keywords: Shape matching

Günter Rote

2007-08-01T23:59:59.000Z

253

THE ECONOMICS OF CONSERVED-ENERGY "SUPPLY" CURVES  

E-Print Network (OSTI)

PWP-028 THE ECONOMICS OF CONSERVED-ENERGY "SUPPLY" CURVES Steven Stoft April 1995 This paper "SUPPLY" CURVES Steven Stoft April 1995 #12;Table of Contents The Economics of Conserved-Energy "Supply is part of the working papers series of the Program on Workable Energy Regulation (POWER). POWER

California at Berkeley. University of

254

PARABOLIC GEODESICS AS PARALLEL CURVES IN PARABOLIC GEOMETRIES  

E-Print Network (OSTI)

PARABOLIC GEODESICS AS PARALLEL CURVES IN PARABOLIC GEOMETRIES MARC HERZLICH Abstract. We give a simple characterization of the parabolic geodesics introduced by Cap, Slovák and Zádník for all parabolic then show that parabolic geodesics can be characterized as the following data: a curve on the manifold

Paris-Sud XI, Université de

255

Fatigue Enhancement of a Carbon Fiber Reinforced Nanocomposite  

E-Print Network (OSTI)

The primary objective of the present investigation is to study the fatigue characteristics of a woven carbon fiber reinforced polymer which has been modified with either amine or fluorine functionalized carbon nanotubes on the fiber-matrix interface. Multi-wall functionalized carbon nanotubes are sprayed onto both sides of each fiber at 0.2-wt % with respect to the fibers. The composites are fabricated using high temperature vacuum assisted resin transfer molding with four-harness satin weave fabric and EPON 862/Epi-Kure W epoxy. Due to the heterogeneous nature of carbon fiber composites, under dynamic loading the composites undergoes a series of complex failure mechanisms: matrix cracking, fiber-matrix debonding, fiber fracture, and buckling. It is believed that debonding of the fiber-matrix interface is the most crucial of these failure mechanisms. Debonding of the fiber-matrix interface critically hinders the matrix’s ability to transfer loads to the fibers, leading to a poor distribution of load. Due to this distribution, one of three failures occurs: individual yarns of fibers are overloaded and fracture, the matrix losses strength and buckles, or a mixture of the two occurs. It will be shown that functionalized multi-wall carbon nanotubes can strengthen the fiber-matrix interface, resulting in fatigue life improvement. The research investigates this behavior for both tension-tension and tension-compression fatiguing. It is believed that improvements will be best at negative R-ratios and high cycle regimes, because the damage is almost entirely matrix dominated occurs under these conditions. Results have shown improvements in static tensile properties of about twenty percent and an order of magnitude improvement in the fatigue life. Fractographic analysis reveals that the nanocomposites can withstand far greater matrix damage prior to final failure. In addition, both optical and scanning electron microscopy indicates that the nanocomposite exhibits reduced fiber-matrix debonding.

Wilkerson, Justin W.

2008-08-19T23:59:59.000Z

256

Application of the key curve method to determining J-R curves for A533B steel  

SciTech Connect

The experimental development is described of a key curve for compact specimens of A533B steel and the use of this experimental key curve to generate the J-Resistance curve directly from the load displacement records without obtaining crack length estimates from unloading compliance, ultrasonics, electric potential or other techniques. Two complete key curve functions were developed, the first using subsized fatique precracked specimens, the second using subsized but machine notched specimens. In each case eight 1/2 T compact specimens with crack lengths from a/W = 0.5 to 0.9 were used to generate a series of digital load displacement records which were assembled in a computer file as the key curve for geometrically similar compact specimens. This key curve can be thought of as defining the locus of load displacement records expected for geometrically similar compact specimens of this material for similar loading conditions if no crack extension were to take place. Deviations between the key curve function and the load displacement record for a particular specimen can then be attributed to crack extension and a calculation for the amount of crack extension can be made. The key curve also allows corrections to be made to J values to account for effects of this crack extension.

Joyce, J.A.

1980-02-01T23:59:59.000Z

257

Program on Technology Innovation: Proceedings of the Expert Workshop on Creep-Fatigue Damage Interaction  

Science Conference Proceedings (OSTI)

As utilities adopt operating practices that involve more severe cycles, it becomes increasingly important to assess the creep-fatigue performance of traditional boiler and turbine components. EPRI brought together key industry experts for the Expert Workshop on Creep-Fatigue Damage Interaction to: Assess and document current creep-fatigue test methods Evaluate analytical methodologies with respect to crack initiation and growth Discuss life prediction methodologies for different applications Assess defi...

2006-11-20T23:59:59.000Z

258

Program on Technology Innovation: The State-of-Knowledge Report on Creep-Fatigue Interaction  

Science Conference Proceedings (OSTI)

This report is part of an ongoing Electric Power Research Institute (EPRI) initiative to review and document the current state of knowledge regarding creep-fatigue. Industry experts have assessed and documented current creep-fatigue test methods, evaluated analytical and life-prediction methodologies, assessed deficiencies in the current understanding and prediction of creep-fatigue damage, and identified issues for future research and development.

2008-09-16T23:59:59.000Z

259

Plant Component Assessment for Creep-Fatigue Damage: Component Assessment Methodologies  

Science Conference Proceedings (OSTI)

This report is part of an ongoing Electric Power Research Institute (EPRI) project to document the current state of knowledge and to address the creep-fatigue assessment of components. An international group of industry and academic experts led by EPRI has assessed and documented creep-fatigue evaluation, analytical and life prediction methodologies, and deficiencies in the current understanding and prediction of creep-fatigue damage. This led to the identification of issues for future research and devel...

2009-12-23T23:59:59.000Z

260

Application of the key curve and multi-specimen techniques to dynamic J-R Curve testing of alloy steel  

SciTech Connect

J-integral R-Curve tests were performed on three point bend specimens of a 3-Ni steel at three loading rates - quasi-static, intermediate (25mm/s) and a drop tower rate (2.54m/s). The key curve and multi-specimen procedures were employed for the higher rate tests and this investigation is focused primarily on details of the test method development. The multi-specimen and key curve techniques were found to yield upper shelf J-R Curves which were in substantial agreement at the elevated loading rates. Numerical smoothing techniques required to apply a key curve method appear to separate the oscillatory high frequency component from the load-displacement record. For the 3-Ni steel tested for this investigation both J/sub Ic/ and T were found to be elevated with increasing loading rate.

Joyce, J.A.; Hackett, E.M.

1986-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Leave-in-Place Laser Scanning for Fatigue Damage Monitoring and ...  

Science Conference Proceedings (OSTI)

Mechanical Behavior in Human Cortical Bone Across Multiple Length Scales: ... Hydrogen-Accelerated Fatigue Crack Growth in a Low-Strength Pipeline Steel.

262

Effect of Cooling Rate on the Fatigue Life of a Nickel-Base ...  

Science Conference Proceedings (OSTI)

Presentation Title, Effect of Cooling Rate on the Fatigue Life of a Nickel-Base ... The Zinagizado Processes as New Electrochemical Alternative to Prevent the ...

263

Modeling Metal Fatigue As a Key Step in PV Module Life Time Prediction (Presentation)  

DOE Green Energy (OSTI)

This presentation covers modeling metal fatigue as a key step in photovoltaic (PV) module lifetime predictions. Described are time-dependent and time-independent case studies.

Bosco, N.

2012-02-01T23:59:59.000Z

264

Effect of Aging Treatment on Fatigue Behavior of an Al-Cu-Mg-Ag Alloy  

Science Conference Proceedings (OSTI)

Tests were performed to characterize the distribution in fatigue lifetimes at a given stress level and the small-crack growth behavior under the two aging ...

265

Fatigue Testing of Carbon Steels and Low-Alloy Steels [Corrosion...  

NLE Websites -- All DOE Office Websites (Extended Search)

Fatigue Testing of Carbon Steels and Low-Alloy Steels Capabilities Materials Testing Environmentally Assisted Cracking (EAC) of Reactor Materials Corrosion PerformanceMetal...

266

Fatigue Resistance of Al-Cu-Li and Comparison with 7xxx ...  

Science Conference Proceedings (OSTI)

We have studied the fatigue resistance of alloys 2050 (AlCuLi alloy belonging to the AIRWARETM family) and 7050. Crack initiation and propagation have been ...

267

A High-Sensitivity Fiber-Optic Sensor for Fatigue Testing  

Science Conference Proceedings (OSTI)

Presentation Title, A High-Sensitivity Fiber-Optic Sensor for Fatigue Testing. Author(s), Nguyen Q Nguyen, Nikhil Gupta. On-Site Speaker (Planned), Nikhil Gupta.

268

Passive solar design handbook  

DOE Green Energy (OSTI)

The Passive Solar Design Handbook, Volume Three updates Volume Two by presenting extensive new data on the optimum mix of conservation and solar direct gain, sunspaces, thermal storage walls, and solar radiation. The direct gain, thermal storage wall, and solar radiation data are greatly expanded relative to the Volume 2 coverage. The needed flexibility to analyze a variety of system designs is accommodated by the large number of reference designs to be encompassed - 94 in contrast to 6 in Volume two - and the large amount of sensitivity data for direct gain and sunspace systems - approximately 1100 separate curves.

Jones, R.W.

1981-01-01T23:59:59.000Z

269

Conservation screening curves to compare efficiency investments to power plants  

SciTech Connect

This paper describes a simplified methodology to compare supply and demand-side resources. The screening curve approach supplements with load shape information the data contained in a supply curve of conserved energy. In addition, a screening curve contains information on competing supply technologies, such as annualized capital costs, variable costs, and cost per delivered kWh. The information in the screening curve allows policymakers to promptly and conveniently compare the relevant parameters affecting supply and demand-side investment decisions. While many sophisticated computer models have evolved to account for the load shape impacts of energy efficiency investments, this sophistication has, by and large, not trickled down to spreadsheet-level or back-of-the-envelope analyses. This methodology allows a simple summary of load shape characteristics based on the output of the more complicated models. It offers many advantages, principal of which is clarity in analyzing supply and demand-side investment choices. This paper first describes how supply-side screening curves have been used in the past, and develops the conceptual tools needed to apply integrated supply/demand screening curves in the least-cost utility planning process. It then presents examples of supply and demand-side technologies and plots them on a representative screening curve. 12 refs., 3 figs., 3 tabs.

Koomey, J.; Rosenfeld, A.H.; Gadgil, A.

1989-10-01T23:59:59.000Z

270

QUEST1 VARIABILITY SURVEY. III. LIGHT CURVE CATALOG UPDATE  

Science Conference Proceedings (OSTI)

This paper reports an update to the QUEST1 (QUasar Equatorial Survey Team, Phase 1) Variability Survey (QVS) light curve catalog, which links QVS instrumental magnitude light curves to Sloan Digital Sky Survey (SDSS) objects and photometry. In the time since the original QVS catalog release, the overlap between publicly available SDSS data and QVS data has increased by 8% in sky coverage and 16,728 in number of matched objects. The astrometric matching and the treatment of SDSS masks have been refined for the updated catalog. We report on these improvements and present multiple bandpass light curves, global variability information, and matched SDSS photometry for 214,941 QUEST1 objects.

Rengstorf, A. W.; Thompson, D. L. [Purdue University Calumet, Department of Chemistry and Physics, 2200 169th St., Hammond, IN 46323 (United States); Mufson, S. L.; Honeycutt, R. K.; Adams, B.; Baltay, C.; Gebhard, M. [Indiana University, 727 E. 3rd St., Bloomington, IN 47405 (United States); Andrews, P.; Coppi, P.; Emmet, W. [Yale University, Department of Physics, P.O. Box 208121, New Haven, CT 06250-8121 (United States); Vivas, A. K.; Abad, C.; Bongiovanni, A.; Briceno, C.; Bruzual, G.; Prugna, F. Della; Hernandez, J. [Centro de Investigaciones de AstronomIa, Apartado Postal 264, Merida 5101-A (Venezuela, Bolivarian Republic of); Bailyn, C. [Yale University, Department of Astronomy, P.O. Box 208101, New Haven, CT 06250-8101 (United States); Ferrin, I.; Fuenmayor, F. [Universidad de Los Andes, Apartado Postal 26, Merida 5251 (Venezuela, Bolivarian Republic of)], E-mail: adamwr@calumet.purdue.edu (and others)

2009-03-15T23:59:59.000Z

271

An analysis of muscle fatigue due to complex tasks and its relation to the strain index  

E-Print Network (OSTI)

The Strain Index was originally designed to analyze mono-task jobs. An experiment using a grip dynamometer was used to simulate six multiple task jobs to study the effect of complex tasks on localized muscle fatigue and to evaluate six different models used to calcula te a Complex Strain Index score. These models included average Strain Index score, unadjusted summation, duration adjusted summation, complex equation, minimum intensity, and peak intensity. Two methods of calculating a continuous Strain Index score were also analyzed. Ratings of perceived exertion, hand and forearm fatigue and discomfort, Difficulty Rating, maximum voluntary contraction (MVC), and percent strength loss were recorded for each of the six treatments. Electromyography (EMG) was also recorded for the 24 subjects (12 males and females) who completed the experiment. The EMG signal was analyzed using root mean square (RMS), initial mean power frequency (IMnPF), and slope of the mean power frequency (MnPF). Each treatment, lasting one hour each, contained a primary exertion (Task 1) of either 10% or 40% MVC for three seconds and a secondary exertion (Task 2) of either 10% or 40% MVC for one or three seconds. Subjective variables linearly increased (R2 > 0.88) over the duration of the treatments and significantly differed between treatments (p 0.05). A significant difference was found for MnPF slope pre and post treatment, but no treatment effect was found (p > 0.05). The complex equation method of calculating a Strain Index score was the only model of the six evaluated that met all criteria for being an acceptable method of calculating a Complex Strain Index score. The two continuous methods presented for calculating a Strain Index score should not be used for job analysis until further research evaluates their reliability, validity, and critical scores for Hazard Classification.

Stephens, John-Paul

2006-08-01T23:59:59.000Z

272

Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies  

Science Conference Proceedings (OSTI)

The primary goal of this project is to increase the fatigue life of a welded-joint by 10 times and to reduce energy use by 25% through product performance and productivity improvements using an integrated modeling approach. The fatigue strength of a welded-joint is currently the bottleneck to design high performance and lightweight welded structures using advanced materials such as high strength steels. In order to achieve high fatigue strength in a welded-joint it is necessary to manage the weld bead shape for lower stress concentration, produce preferable residual stress distribution, and obtain the desired microstructure for improved material toughness and strength. This is a systems challenge that requires the optimization of the welding process, the welding consumable, the base material, as well as the structure design. The concept of virtual welded-joint design has been proposed and established in this project. The goal of virtual welded-joint design is to develop a thorough procedure to predict the relationship of welding process, microstructure, property, residual stress, and the ultimate weld fatigue strength by a systematic modeling approach. The systematic approach combines five sub-models: weld thermal-fluid model, weld microstructure model, weld material property model, weld residual stress model, and weld fatigue model. The systematic approach is thus based on interdisciplinary applied sciences including heat transfer, computational fluid dynamics, materials science, engineering mechanics, and material fracture mechanics. The sub-models are based on existing models with further development. The results from modeling have been validated with critical experiments. The systematic modeling approach has been used to design high fatigue resistant welds considering the combined effects of weld bead geometry, residual stress, microstructure, and material property. In particular, a special welding wire has been developed in this project to introduce compressive residual stress at weld toe for weld fatigue resistance.

Yang, Z.; Dong, P.; Liu, S.; Babu, S.; Olson, G.; DebRoy, T.

2005-04-15T23:59:59.000Z

273

An Evaluation of Free- and Fixed-Vane Flowmeters with Curved- and Flat-Bladed Savonius Rotors  

Science Conference Proceedings (OSTI)

Speed and direction performances of flowmeters, designed by the authors for in-house use, employing an Aanderaa-type curved-bladed Savonius rotor and a free vane and an Aanderaa-type flat-bladed Savonius rotor and a fixed vane, are discussed. It ...

Antony Joseph; Ehrlich Desa

1994-04-01T23:59:59.000Z

274

21-PWR WASTE PACKAGE WITH ABSORBER PLATES LOADING CURVE EVALUATION  

Science Conference Proceedings (OSTI)

The objective of this calculation is to evaluate the required minimum burnup as a function of initial pressurized water reactor (PWR) assembly enrichment that would permit loading of spent nuclear fuel into the 21 PWR waste package with absorber plates design as provided in Attachment IV. This calculation is an example of the application of the methodology presented in the ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003). The scope of this calculation covers a range of enrichments from 0 through 5.0 weight percent U-235, and a burnup range of 0 through 45 GWd/MTU. Higher burnups were not necessary because 45 GWd/MTU was high enough for the loading curve determination. This activity supports the validation of the use of burnup credit for commercial spent nuclear fuel applications. The intended use of these results will be in establishing PWR waste package configuration loading specifications. Limitations of this evaluation are as follows: (1) The results are based on burnup credit for actinides and selected fission products as proposed in YMP (2003, Table 3-1) and referred to as the ''Principal Isotopes''. Any change to the isotope listing will have a direct impact on the results of this report. (2) The results are based on 1.5 wt% Gd in the Ni-Gd Alloy material and having no tuff inside the waste package. If the Gd loading is reduced or a process to introduce tuff inside the waste package is defined, then this report would need to be reevaluated based on the alternative materials. This calculation is subject to the ''Quality Assurance Requirements and Description'' (QARD) (DOE 2004) because it concerns engineered barriers that are included in the ''Q-List'' (BSC 2004k, Appendix A) as items important to safety and waste isolation.

J.M. Scaglione

2004-12-17T23:59:59.000Z

275

Solvability of small curves of genus 2 - CECM  

E-Print Network (OSTI)

Supporting data: files.zip (2.7Mb). Contains: AllCurves.m (22Mb): Contains all square free polynomials of degree 5 or 6 with integer coordinates between -3 and ...

276

Development of an Equivalent Wind Plant Power-Curve: Preprint  

SciTech Connect

Development of an equivalent wind plant power-curve becomes highly desirable and useful in predicting plant output for a given wind forecast. Such a development is described and summarized in this paper.

Wan, Y. H.; Ela, E.; Orwig, K.

2010-06-01T23:59:59.000Z

277

Convex hulls of a curve in control theory  

Science Conference Proceedings (OSTI)

A classification is obtained for typical singularities of the local transitivity sets of control systems on three-dimensional manifolds with nonconvex indicatrices that are closed smooth spatial curves. Bibliography: 8 titles.

Kurbatskii, Aleksei N [Moscow School of Economics of Lomonosov MSU, Moscow (Russian Federation)

2012-03-31T23:59:59.000Z

278

DOE Updated U.S. Geothermal: Supply Curve (Presentation)  

NLE Websites -- All DOE Office Websites (Extended Search)

2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov The Parker Ranch installation in Hawaii Geothermal Technologies Program (GTP) DOE Updated U.S. Geothermal Supply Curve Chad Augustine National Renewable Energy Laboratory Strategic Energy Analysis Center Chad.Augustine@nrel.gov February 1, 2010 Chad Augustine (NREL) Katherine R. Young (NREL) Arlene Anderson (DOE-GTP) NREL/PR-6A2-47527 Pacific Gas & Electric/PIX 00059 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. 2 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

279

Forecasting distribution system loads using curve shape clustering  

SciTech Connect

Trending using curve fitting to past small area load growth is an economical but not highly accurate method of forecasting loads for distribution planning. A new trending method uses clustering of historical load at the small area level as the forecast algorithm. This new method has significant performance advantages over normal curve fit methods and can be implemented in 16 bit integer arithmetic on most computers. The method and test results are discussed in detail.

Willis, H.L.; Northcote-Green, J.E.D.; Schauer, A.E.; Vismor, T.D.

1983-04-01T23:59:59.000Z

280

Phase light curves for extrasolar Jupiters and Saturns  

E-Print Network (OSTI)

We predict how a remote observer would see the brightness variations of giant planets similar to Jupiter and Saturn as they orbit their central stars. We model the geometry of Jupiter, Saturn and Saturn's rings for varying orbital and viewing parameters. Scattering properties for the planets and rings at wavelenghts 0.6-0.7 microns follow Pioneer and Voyager observations, namely, planets are forward scattering and rings are backward scattering. Images of the planet with or without rings are simulated and used to calculate the disk-averaged luminosity varying along the orbit, that is, a light curve is generated. We find that the different scattering properties of Jupiter and Saturn (without rings) make a substantial difference in the shape of their light curves. Saturn-size rings increase the apparent luminosity of the planet by a factor of 2-3 for a wide range of geometries. Rings produce asymmetric light curves that are distinct from the light curve of the planet without rings. If radial velocity data are available for the planet, the effect of the ring on the light curve can be distinguished from effects due to orbital eccentricity. Non-ringed planets on eccentric orbits produce light curves with maxima shifted relative to the position of the maximum planet's phase. Given radial velocity data, the amount of the shift restricts the planet's unknown orbital inclination and therefore its mass. Combination of radial velocity data and a light curve for a non-ringed planet on an eccentric orbit can also be used to constrain the surface scattering properties of the planet. To summarize our results for the detectability of exoplanets in reflected light, we present a chart of light curve amplitudes of non-ringed planets for different eccentricities, inclinations, and the viewing azimuthal angles of the observer.

Ulyana A. Dyudina; Penny D. Sackett; Daniel D. R. Bayliss; Sara Seager; Carolyn C. Porco; Henry B. Throop; Luke Dones

2004-06-17T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Time-domain Fatigue Response and Reliability Analysis of Offshore Wind Turbines with  

E-Print Network (OSTI)

-domain based simulation model of 750 kW land-based wind turbine Gear contact fatigue analysis of a wind of 750 kW land-based wind turbine Gear contact fatigue analysis of a wind turbine drive train under response and reliability analysis #12;Time domain based simulation model of 750 kW land-based wind turbine

Nørvåg, Kjetil

282

Research on Bolt's Fatigue Characters and Parametric Modeling Based on GL  

Science Conference Proceedings (OSTI)

Base on the ¡¶Guideline for the Certification of Wind Turbines¡·, this paper describes the problem of bolt fatigue broken and its mechanical behaviors under an alternating load. In order to solve the problem and to find a regulation, various types ... Keywords: Bolt connection, Fatigue, GL, Wind turbine, FEM, Parametric modeling

Jingwei Zhou, Wufu Ma

2012-07-01T23:59:59.000Z

283

Fatigue Crack Growth Characteristics of Thin Sheet Titanium Alloy Ti 6-2-2-2-2  

Science Conference Proceedings (OSTI)

Fatigue crack growth rates of Ti 6-2-2-2-2 as a function of stress ratio, temperature (24 or 177 degrees C), tensile orientation and environment (laboratory air or ultrahigh vacuum) are presented. Fatigue crack growth rates of Ti 6-2-2-2-2 are also compared ...

Smith Stephen W.; Piascik Robert S.

2001-03-01T23:59:59.000Z

284

FATIGUEPRO(TM) On-Line Fatigue Monitoring System: Demonstration at the Quad Cities BWR  

Science Conference Proceedings (OSTI)

The FATIGUEPRO system can improve nuclear plant reliability and contribute to plant life extension by calculating accumulated fatigue usage for critical components. In cooperation with Commonwealth Edison Company (CECo), EPRI demonstrated the system at the Quad Cities unit 2 BWR to monitor fatigue on-line.

1989-02-02T23:59:59.000Z

285

Enhanced fatigue and aging resistance using reactive powders in the optical fiber buffer coating V. V. Rondinella  

E-Print Network (OSTI)

Enhanced fatigue and aging resistance using reactive powders in the optical fiber buffer coating V causes a dramatic improvement in the fatigue and aging resistance both in aqueous and in constant for the surface roughening that causes the fatigue knee and strength degradation during zero-stress aging

Matthewson, M. John

286

Corrosion Fatigue Testing of GMAW and Laser Weld Overlays  

Science Conference Proceedings (OSTI)

This report is an update of EPRI’s ongoing laboratory study on corrosion fatigue cracking of weld overlays, applied to waterwalls of boilers suffering high wastage. At this point the work is not complete. At least one more year of testing is needed to study the effect of all variables affecting circumferential cracking of weld overlays. Thus all conclusions based on the work completed to date should be considered preliminary. Major trends observed to date are that the corrosivity of the environment along...

2005-12-09T23:59:59.000Z

287

Machining of Aircraft Titanium with Abrasive-Waterjets for Fatigue Critical Applications  

Science Conference Proceedings (OSTI)

Laboratory tests were conducted to determine the fatigue performance of AWJ-machined aircraft titanium. Dog-bone specimens machined with AWJs were prepared and tested with and without sanding and dry-grit blasting with Al2O3 as secondary processes. The secondary processes were applied to remove the visual appearance of AWJ-generated striations and to clean up the garnet embedment. The fatigue performance of AWJ-machined specimens was compared with baseline specimens machined with CNC milling. Fatigue test results not only confirmed the findings of the aluminum dog-bone specimens but also further enhance the fatigue performance. In addition, titanium is known to be notoriously difficult to cut with contact tools while AWJs cut it 34% faster than stainless steel. AWJ cutting and dry-grit blasting are shown to be a preferred combination for processing aircraft titanium that is fatigue critical.

Liu, H. T.; Hovanski, Yuri; Dahl, Michael E.

2010-10-04T23:59:59.000Z

288

Machining of Aircraft Titanium with Abrasive-Waterjets for Fatigue Critical Applications  

Science Conference Proceedings (OSTI)

Laboratory tests were conducted to determine the fatigue performance of abrasive-waterjet- (AWJ-) machined aircraft titanium. Dog-bone specimens machined with AWJs were prepared and tested with and without sanding and dry-grit blasting with Al2O3 as secondary processes. The secondary processes were applied to remove the visual appearance of AWJ-generated striations and to clean up the garnet embedment. The fatigue performance of AWJ-machined specimens was compared with baseline specimens machined with CNC milling. Fatigue test results of the titanium specimens not only confirmed our previous findings in aluminum dog-bone specimens but in comparison also further enhanced the fatigue performance of the titanium. In addition, titanium is known to be difficult to cut, particularly for thick parts, however AWJs cut the material 34% faster han stainless steel. AWJ cutting and dry-grit blasting are shown to be a preferred ombination for processing aircraft titanium that is fatigue critical.

Liu, H. T.; Hovanski, Yuri; Dahl, Michael E.

2012-02-01T23:59:59.000Z

289

Effect of seawater environmental exposure on fatigue properties of polyethylene pipe  

DOE Green Energy (OSTI)

One laboratory study at NIT was reported to show an unexpected decrease in crystallinity for a polyethylene material exposed to fatigue loading in a synthetic seawater solution. High density polyethylene Sclairpipe, from the OTEC-1 cold water pipe, was evaluated for resistance to corrosion fatigue in natural seawater. Intermediate crystallinity measurements (via bulk density) showed no effect of corrosion fatigue exposure. Heat of fusion (a relative indicator of crystallinity) also showed no effect of the exposure. Seawater exposure produced no significant change in tensile strength. One failure was observed during the corrosion fatigue tests and was attributed to porosity observed by fractography. These data suggest that high density polyethylene is not significantly sensitive to degradation of fatigue strength in natural seawater.

Tipton, D G

1980-10-01T23:59:59.000Z

290

Fatigue of quasi-isotropic composite cylinders under tension-tension loading  

Science Conference Proceedings (OSTI)

A tension fatigue life prediction methodology based on a through-thickness damage accumulation model is used to predict the fatigue failure of composite coupon specimens. Its applicability to thin-walled cylindrical specimens is investigated by comparing the fatigue behavior of composite coupon specimens to that of composite thin-walled cylindrical specimens. AS4/3501-6 graphite-epoxy coupon specimens and thin-walled cylinder specimens with the same layup sequence of (0/+/- 45/90)s were tested under static and fatigue loading conditions. Reasonably good agreement is found between the measured and predicted lives of the coupon specimens. Although the ultimate stresses of coupon and cylindrical specimens are different, it is observed that their fatigue lives at the same percentage of ultimate stress are nearly identical, independent of the coupon edge effect. 23 refs.

Norman, T.L.; Civelek, T.S.; Prucz, J. (West Virginia Univ., Morgantown (United States))

1992-11-01T23:59:59.000Z

291

Transformation Induced Fatigue of Ni-Rich NiTi Shape Memory Alloy Actuators  

E-Print Network (OSTI)

In this work the transformation induced fatigue of Ni-rich NiTi shape memory alloys (SMAs) was investigated. The aerospace industry is currently considering implementing SMA actuators into new applications. However, before any new applications can be put into production they must first be certified by the FAA. Part of this certification process includes the actuator fatigue life. In this study, as-received and polished at dogbone SMA specimens underwent transformation induced fatigue testing at constant loading. The constant applied loading ranged from 100 MPa to 200 MPa. Specimens were thermally cycled through complete actuation (above Af to below Mf ) by Joule heating and environmental cooling. There were three cooling environments studied: liquid, gaseous nitrogen and vortex cooled air. It was shown that polished specimens had fatigue lives that were two to four times longer than those of as-received specimens. Test environment was also found to have an effect on fatigue life. Liquid cooling was observed to be corrosive, while the gaseous nitrogen and vortex air cooling were observed to be non-corrosive. The two non-corrosive cooling environments performed similarly with specimen fatigue lives that were twice that of specimens fatigue tested in the corrosive cooling environment. Transformation induced fatigue testing of polished specimens in a non-corrosive environment at 200 MPa had an average fatigue life of 14400 actuation cycles; at 150 MPa the average fatigue life was 20800 cycles and at 100 MPa it was 111000 cycles. For all specimens constant actuation from the beginning of testing until failure was observed, without the need for training. Finally, a microstructural study showed that the Ni3Ti precipitates in the material were one of the causes of crack initiation and propagation in the actuators.

Schick, Justin Ryan

2009-12-01T23:59:59.000Z

292

Variations in gear fatigue life for different wind turbine braking strategies  

SciTech Connect

A large number of gearbox failures have occurred in the wind industry in a relatively short period, many because service loads were underestimated. High-torque transients that occur during starting and stopping are difficult to predict and may be overlooked in specifying gearbox design. Although these events comprise a small portion of total load cycles, they can be the most damaging. The severity of these loads varies dramatically with the specific configuration of the wind turbine. The large number of failures in Danish-designed Micon 65 wind turbines prompted this investigation. The high-speed and low-speed shaft torques were measured on a two-stage helical gearbox of a single Micon 65 turbine. Transient events and normal running loads were combined statistically to obtain a typical annual load spectrum. The pitting and bending fatigue lives of the gear teeth were calculated by using Miner's rule for four different high-speed shaft brake configurations. Each breaking scenario was run for both a high- and a low-turbulence normal operating load spectrum. The analysis showed increases in gear life by up to a factor of 25 when the standard high-speed shaft brake is replaced with a dynamic brake or modified with a damper. 9 refs., 9 figs., 3 tabs.

McNiff, B.P. (Second Wind, Inc., Somerville, MA (USA)); Musial, W.D. (Solar Energy Research Inst., Golden, CO (USA)); Errichello, R. (GEARTECH, Albany, CA (USA))

1991-06-01T23:59:59.000Z

293

Variations in gear fatigue life for different wind turbine braking strategies  

DOE Green Energy (OSTI)

A large number of gearbox failures have occurred in the wind industry in a relatively short period, many because service loads were underestimated. High-torque transients that occur during starting and stopping are difficult to predict and may be overlooked in specifying gearbox design. Although these events comprise a small portion of total load cycles, they can be the most damaging. The severity of these loads varies dramatically with the specific configuration of the wind turbine. The large number of failures in Danish-designed Micon 65 wind turbines prompted this investigation. The high-speed and low-speed shaft torques were measured on a two-stage helical gearbox of a single Micon 65 turbine. Transient events and normal running loads were combined statistically to obtain a typical annual load spectrum. The pitting and bending fatigue lives of the gear teeth were calculated by using Miner's rule for four different high-speed shaft brake configurations. Each breaking scenario was run for both a high- and a low-turbulence normal operating load spectrum. The analysis showed increases in gear life by up to a factor of 25 when the standard high-speed shaft brake is replaced with a dynamic brake or modified with a damper. 9 refs., 9 figs., 3 tabs.

McNiff, B.P. (Second Wind, Inc., Somerville, MA (USA)); Musial, W.D. (Solar Energy Research Inst., Golden, CO (USA)); Errichello, R. (GEARTECH, Albany, CA (USA))

1991-06-01T23:59:59.000Z

294

Synthetic Spectra and Light Curves of Interacting Binaries and Exoplanets with Circumstellar Material: SHELLSPEC  

E-Print Network (OSTI)

Program SHELLSPEC is designed to calculate light-curves, spectra and images of interacting binaries and extrasolar planets immersed in a moving circumstellar environment which is optically thin. It solves simple radiative transfer along the line of sight in moving media. The assumptions include LTE and optional known state quantities and velocity fields in 3D. Optional (non)transparent objects such as a spot, disc, stream, jet, ufo, shell or stars may be defined (embedded) in 3D and their composite synthetic spectrum calculated. Roche model can be used as a boundary condition for the radiative transfer. Recently a new model of the reflection effect, dust and Mie scattering were incorporated into the code. $\\epsilon$ Aurigae is one of the most mysterious objects on the sky. Prior modeling of its light-curve assumed dark, inclined, disk of dust with the central hole to explain the light-curve with a sharp mid-eclipse brightening. Our model consists of two geometrically thick flared disks. Internal optically thi...

Budaj, Jan

2011-01-01T23:59:59.000Z

295

Implementation of a Two-Axis Servo-Hydraulic System for Full-Scale Fatigue Testing of Wind Turbine Blades  

DOE Green Energy (OSTI)

Recently, the blade fatigue testing capabilities at NREL were upgraded from single-axis to two-axis loading. To implement this, several practical challenges were addressed, as hardware complexity increased dramatically with two actuators applying the loads at right angles to each other. A custom bellcrank was designed and implemented to minimize the load angle errors and to prevent actuator side loading. The control system was upgraded to accept load and displacement feedback from two actuators. The inherent long strokes uniquely associated with wind turbine blade-tests required substantial real-time corrections for both the control and data systems. A custom data acquisition and control system was developed using a National Instruments LabVIEW platform that interfaces with proprietary servo-hydraulic software developed by MTS Corporation. Before testing, the program is run under quasi-static (slow speed) conditions and iterates to determine the correct operational control parameters for the controller, taking into consideration geometry, test speed, and phase angle errors between the two actuators. Comparisons are made between single-axis and two-axis test loads using actual test load data and load uncertainties are qualitatively described. To date, two fatigue tests have been completed and another is currently ongoing using NREL's two-axis capability.

Hughes, S. D.; Musial, W. D. [National Renewable Energy Lab., Golden, CO (US); Stensland, T. [Stensland Technologies (US)

1999-09-09T23:59:59.000Z

296

How to Measure a Camera's Response Curve from Scratch  

E-Print Network (OSTI)

This paper describes how the response curve of a video camera can be determined with the aid of a sheet of paper and two desk lamps only. The calibration process is based on the superposition law of incoherent light and does not make use of any calibrated measurement instrument. 1 Introduction Digitizing and processing of video images has steadily gained importance in recent years. Various applications profit from this technique, in particular industrial inspection, optical measuring, desktop publishing, and remote sensing. For applications which are sensitive to image quality an exact characterization of the properties of the data acquisition equipment is essential. Knowing the equipment's response curve is especially important because many applications either rely on a linear response curve or on a specific power law (fl-correction). Relying on the data sheets of the measurement equipment is only partially useful because 1. The data is often missing (e.g. for the digitizer). 2. The ...

Martin Bichsel; Krystyna W. Ohnesorge

1993-01-01T23:59:59.000Z

297

DEVELOPING FLOW AND HEAT TRANSFER IN STRONGLY CURVED DUCTS OF RECTANGULAR CROSS-SECTION  

E-Print Network (OSTI)

Forced Convection Heat Transfer in Curved RectangularInfluence of Curvature on Heat Transfer to IncompressibleT. , "Forced Convective Heat Transfer in a Curved Channel

Yee, G.

2010-01-01T23:59:59.000Z

298

The shape of heavy ion upset cross section curves  

Science Conference Proceedings (OSTI)

An approach is developed to describe heavy ion single event upset cross section curves. It accounts for all significant mechanisms which cause the curve to deviate from ideal, step function-like behavior. The method is developed in terms of the charge deposited by an incident ion in a memory cell and is therefore free of ambiguities associated with the effective LET concept. It is suggested that this type of approach is an improvement over current methods used to characterize a memory response to accelerator tests. This has significant implications for predicting space upset rates.

Xapsos, M.A. (Naval Research Lab., Washington, DC (United States). Radiation Effects Branch); Weatherford, T.R.; Shapiro, P. (SFA, Inc., Landover, MD (United States))

1993-12-01T23:59:59.000Z

299

Logging and Agricultural Residue Supply Curves for the Pacific Northwest  

DOE Green Energy (OSTI)

This report quantified the volume of logging residues at the county level for current timber harvests. The cost of recovering logging residues was determined for skidding, yearding, loading, chipping and transporting the residues. Supply curves were developed for ten candidate conversion sites in the Pacific Northwest Region. Agricultural field residues were also quantified at the county level using five-year average crop yields. Agronomic constraints were applied to arrive at the volumes available for energy use. Collection costs and transportation costs were determined and supply curves generated for thirteen candidate conversion sites.

Kerstetter, James D.; Lyons, John Kim

2001-01-01T23:59:59.000Z

300

Application of Abrasive-Waterjets for Machining Fatigue-Critical Aircraft Aluminum Parts  

SciTech Connect

The effects of dry-grid blasting of AWJ-machined dog-bone specimens of aircraft aluminum with aluminum oxide abrasives were investigated in terms of enhancement in fatigue performance and mitigating concerns of abrasive contamination. Results obtained from fatigue tests have indicated that the surface roughness, Ra, of AWJ-induced striations is inversely proportional to the fatigue life. The fatigue life of AWJ-machined and baseline specimens, excluding those processed with dry-grit blasting, decreases with the increase in Ra. Removal of the striations with dry-grit blasting until they disappear visually only reduces Ra from 3.5 to 2.4 ?m and is still higher than that of the conventionally machined edges with Ra = 1.6 ?m. From the surface roughness point of view, the fatigue life of the dry-grit blasted specimens should not have exceeded that of the baseline counterparts. Yet the dry-grit blasting process has extended the fatigue life of the AWJ-machined specimens and the baseline counterparts by more than four and three times, respectively. The extraordinary boost in the fatigue performance is believed to be attributed to the induction of residual compressive stresses by dry-grit blasting. Such a belief was subsequent confirmed quantitatively through measurements of residual compressive stresses. Dry-grid blasting can be carried out efficiently and cost effectively by stacking AWJ-machined parts together. The benefits gained from dry-grit blasting simply outweigh the marginal cost increase.

Liu, H. T.; Hovanski, Yuri; Dahl, Michael E.; Zeng, J.

2010-08-19T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

High-Cycle Fatigue of Single-Crystal Silicon Thin Films  

E-Print Network (OSTI)

When subjected to alternating stresses, most materials degrade, e.g., suffer premature failure, due to a phenomenon known as fatigue. It is generally accepted that in brittle materials, such as ceramics, fatigue can only take place in toughened solids, i.e., premature fatigue failure would not be expected in materials such as single crystal silicon. The results of this study, however, appear to be at odds with the current understanding of brittle material fatigue. Twelve thin-film ( 20 m thick) single crystal silicon specimens were tested to failure in a controlled air environment (30 0.1 C, 50 2% relative humidity). Damage accumulation and failure of the notched cantilever beams were monitored electrically during the "fatigue life" test. Specimen lives ranged from about 10 s to 48 days, or 1 10 6 to 1 10 11 cycles before failure over stress amplitudes ranging from approximately 4 to 10 GPa. A variety of mechanisms are discussed in light of the fatigue life data and fracture surface evaluation. [642] Index Terms---Fatigue failure, MEMS devices, single-crystal silicon, thin films.

Christopher L. Muhlstein; Stuart B. Brown; Robert O. Ritchie

2001-01-01T23:59:59.000Z

302

Effect of cerium and impurities on fatigue and fracture properties of 8090 alloy sheets  

Science Conference Proceedings (OSTI)

The objective of the present study is to examine the effect of a rare earth addition, Ce, and some impurities, Fe, Si, Na and K, on the fatigue and fracture properties of 8090 Al-Li alloy sheet by means of the determinations for the fatigue life (N{sub f}) under a constant stress amplitude, fatigue crack propagation (FCP) rates and plane stress fracture toughness. Impurity Fe and Si in 8090 alloy sheets increase the fatigue crack propagation rates and impair the fracture properties although they could not bring about significant effect on the fatigue life under the test conditions maximum cyclic stress of 280 MPa, load ratio of 0.1 and Fe + Si content of 0.24%. Impurity Na and K in 8090 alloy sheets reduce the fracture properties and fatigue life. When the level stress intensity factor is higher, or {Delta} K>10{sup 1.1} Mpam{sup 1/2} in the test, Na and K markedly increase the fatigue crack propagation rates. Ce addition in 8090 alloy sheets containing a certain amount of Fe and Si impurities could suppress the effects of Na and K impurities on the fracture behavior. Adding about 0.28% Ce in 8090 alloy containing trace Fe and Si impurities improves the crack propagation resistance and plane stress fracture toughness. However, adding Ce from 0.10% to 0.29% is unprofitable to the fatigue life of 8090 alloy containing more impurities. There are more and coarser Ce-containing compound particles in the alloy sheets with high Ce content. These particles could produce a detrimental effect on the fatigue properties.

Meng Liang; Zheng Xiulin [Northwestern Polytechnical Univ., Xi`an (China). Dept. of Materials Science and Engineering

1995-07-01T23:59:59.000Z

303

On Modeling and Forecasting Time Series of Smooth Curves  

E-Print Network (OSTI)

/fertility rate curves (Hyndman and Ullah, 2007; Erbas et al., 2007). Other examples include electricity system the rates are unobservable; hence one needs to forecast future rate profiles based on historical call of telephone customer service centers, where forecasts of daily call arrival rate profiles are needed

Shen, Haipeng

304

Experience Curves and Solar PV Fred Heutte, Senior Policy Associate  

E-Print Network (OSTI)

the historical advantage fossil based electricity has had will reverse, with significant consequences for future Electricity Coordinating Council's transmission planning for the 10-year Common Case based plan, and even more of evidence suggests staying with the consensus experience curve estimate ­ a Learning Rate of 20% for solar

305

Real-time rendering of textures with feature curves  

Science Conference Proceedings (OSTI)

The standard bilinear interpolation on normal maps results in visual artifacts along sharp features, which are common for surfaces with creases, wrinkles, and dents. In many cases, spatially varying features, like the normals near discontinuity curves, ... Keywords: Curvilinear feature rendering, GPU algorithms, distance function, normal mapping, resolution independence

Evgueni Parilov; Denis Zorin

2008-03-01T23:59:59.000Z

306

Stochastic Analysis of Wind Turbine Power Curves Edgar Anahua  

E-Print Network (OSTI)

procedure (IEC 61400-12) for power performance charac- terization of a single wind turbines is shown by the standard IEC 61400-12 3 [12]. In this standard procedure the power curve of a single wind turbine of the blade pitch angle system of a wind turbine [9]. The phase averaged P(t,t ) function depends on the time

Peinke, Joachim

307

Projecting diffusion along the normal bundle of a plane curve  

E-Print Network (OSTI)

The purpose of this paper is to provide new formulas for the estimation of the effective diffusion coefficient of an equation of Fick-Jacob's type obtained by projecting the two-dimensional diffusion equation along the normal direction of an arbitrary plane curve.

Carlos Valero Valdes; Rafael Herrera Guzman

2013-08-21T23:59:59.000Z

308

Offshore Wind Resource Global Wind Potential Supply Curves by...  

Open Energy Info (EERE)

Offshore Wind Resource Global Wind Potential Supply Curves by Country, Class, and Depth (quantities in GW)
2012-07-12T22:51:45Z 2012-07-13T20:49:20Z I am submitting data from...

309

Analytic Definition of Curves and Surfaces by Parabolic Blending  

E-Print Network (OSTI)

A procedure for interpolating between specified points of a curve or surface is described. The method guarantees slope continuity at all junctions. A surface panel divided into p x q contiguous patches is completely specified by the coordinates of (p+1) x (q+1) points. Each individual patch, however, depends parametrically on the coordinates of 16 points, allowing shape flexibility and global conformity.

A. W. Overhauser

2005-03-22T23:59:59.000Z

310

Complex Fluid Analysis with the Advanced Distillation Curve Approach  

E-Print Network (OSTI)

the flask. Heaters are controlled by a model predictive proportional-integral-derivative (PID) controllerComplex Fluid Analysis with the Advanced Distillation Curve Approach Thomas J. Bruno, Lisa S. Ott of petroleomics, as asserted by Marshall and Rodgers, include quantitation of species, modeling, and informatics

311

The Foundation and Application of Horizontal Well Deliverability Type Curves  

Science Conference Proceedings (OSTI)

As a development technique to improve oil and gas deliverability, horizontal wells have recently become an important technical support to develop low permeability or extra-low permeability and unconventional oil and gas fields. Therefore, it is quite ... Keywords: Horizontal well, Impermeable and circular boundary reservoir, Stehfest numerical inversion, Blasingame decline curves, Single well dynamic reserves

Rong Wang; Yonggang Duan; Quantang Fang; Cao Tingkuan; Mingqiang Wei

2011-10-01T23:59:59.000Z

312

The Investigation of Newly Designed Transformer Windings with Reduced Thickness of Oil-Impregnated Paper Insulation.  

E-Print Network (OSTI)

??For determining the insulation dimensions, Smit Transformers uses a so called “design curve”. As the oil-impregnated paper insulation of the windings has been improved, a… (more)

Singuran, A.I.

2012-01-01T23:59:59.000Z

313

Thermal fatigue behavior of US and Russian grades of beryllium  

Science Conference Proceedings (OSTI)

A novel technique has been used to test the relative low cycle thermal fatigue resistance of different grades of US and Russian beryllium which is proposed as plasma facing armor for fusion reactor first wall, limiter, and divertor components. The 30 KW electron beam test system at Sandia National Laboratories was used to sweep the beam spot along one direction at 1 Hz. This produces a localized temperature ``spike`` of 750{degrees}C for each pass of the beam. Large thermal stress in excess of the yield strength are generated due to very high spot heat flux, 250 MW/m{sup 2}. Cyclic plastic strains on the order of 0.6% produced visible cracking on the heated surface in less than 3000 cycles. An in-vacuo fiber optic borescope was used to visually inspect the beryllium surfaces for crack initiation. Grades of US beryllium tested included: S-65C, S-65H, S-200F, S-300F-H, Sr-200, I-400, extruded high purity. HIP`d sperical powder, porous beryllium (94% and 98% dense), Be/30% BeO, Be/60% BeO, and TiBe{sub 12}. Russian grades included: TGP-56, TShGT, DShG-200, and TShG-56. Both the number of cycles to crack initiation, and the depth of crack propagation, were measured. The most fatigue resistant grades were S-65C, DShG-200, TShGT, and TShG-56. Rolled sheet Be(SR-200) showed excellent crack propagation resistance in the plane of rolling, despite early formation of delamination cracks. Only one sample showed no evidence of surface melting, Extruded (T). Metallographic and chemical analyses are provided. Good agreement was found between the measured depth of cracks and a 2-D elastic-plastic finite element stress analysis.

Watson, R.D.; Youchison, D.L. [Sandia National Labs., Albuquerque, NM (United States); Dombrowski, D.E. [Brush Wellman, Inc., Cleveland, OH (United States); Guiniatouline, R.N. [Efremov Institute, St. Petersburg (USSR); Kupriynov, I.B. [Russian Inst. of Inorganic Materials, Moscow (USSR)

1996-02-01T23:59:59.000Z

314

A computer-controlled automated test system for fatigue and fracture testing  

SciTech Connect

A computer-controlled system consisting of a servohydraulic test machine, an in-house designed test controller, and a desktop computer has been developed for performing automated fracture toughness and fatigue crack growth testing both in the laboratory and in hot cells for remote testing of irradiated specimens. Both unloading compliance and dc-potential drop can be used to monitor crack growth. The test controller includes a dc-current supply programmer, a function generator for driving the servohydraulic test machine to required test outputs, five measurement channels (each consisting of low-pass filter, track/hold amplifier, and 16-bit analog-to-digital converter), and digital logic for various control and data multiplexing functions. The test controller connects to the computer via a 16-bit wide photo-isolated bidirectional bus. The computer, a Hewlett-Packard series 200/300, inputs specimen and test parameters from the operator, configures the test controller, stores test data from the test controller in memory, does preliminary analysis during the test, and records sensor calibrations, specimen and test parameters, and test data on flexible diskette for later recall and analysis with measured initial and final crack length information. During the test, the operator can change test parameters as necessary. 24 refs., 6 figs.

Nanstad, R.K.; Alexander, D.J.; Swain, R.L.; Hutton, J.T.; Thomas, D.L.

1989-01-01T23:59:59.000Z

315

Fatigue expectations in a molybdenum/silicon multilayer under pulsed soft X-ray radiation  

Science Conference Proceedings (OSTI)

The temperature rise in a Mo/a-Si multilayer x-ray reflective film due to radiation absorption is modeled for the first condenser mirror in a projection lithography system such as the one designed by the Advanced Microtechnology Program at LLNL. The radiation load is pulsed at 1000 Hz with a time average intensity of 500mW/cm{sup 2}. This intensity is the expected maximum on the first condenser mirror. The temperature rise is calculated using the integral transform technique. The film is assumed to have the thermal properties of its poorly conducting substrate, yielding a more conservative (higher) temperature estimate. The surface temperature rise is found to range between 35.6{degrees}C and 76.3{degrees}C. The stress due to this rise is greatest in the molybdenum film and ranges between 73MPa and 166MPa compressive. This fluctuating stress level, however, is believed to be insufficient, by a factor of five or so, to cause fatigue failure of the film.

Weber, F.J.; Kassner, M.E. [Oregon State Univ., Corvallis, OR (United States); Stearns, D.G. [Lawrence Livermore National Lab., CA (United States)

1995-01-19T23:59:59.000Z

316

Regulatory Design for RES-E Support Mechanisms: Learning Curves, Market Structure, and Burden-Sharing  

E-Print Network (OSTI)

Drawing from relevant experiences in power systems around the world, this paper offers a critical review of existing policy support mechanisms for RES-E (renewable energy sources for electricity), with a detailed analysis ...

Batlle, Carlos

317

Design model of the FNPB guide system showing the curved cold beam with four  

E-Print Network (OSTI)

's linear accelerator (Linac) provides beam for both high energy physics research and neutron radiationP.O. Box 500, MS 301 · Batavia, IL 60510 Phone: (630) 840-3865 ·FAX: (630) 840-8766 Email: neutrons@niu.edu Neutrons Against Cancer www.neutrontherapy.niu.edu Institute fo a Institute for Neutron Therapy at Fermilab

318

Materials Reliability Program: Computer-Based NDE Training for Thermal Fatigue Cracking (MRP-36, Revision 2)  

Science Conference Proceedings (OSTI)

This product comes packaged together and contains both #1022875, Materials Reliability Program: NDE Technology for Detection of Thermal Fatigue Damage in Piping, (MRP-23, Revision 1) and Product #1024915, Computer-Based NDE Training for Thermal ...

2012-11-20T23:59:59.000Z

319

Effect of nano-scale twinning on the fracture, fatigue and wear properties of copper  

E-Print Network (OSTI)

Grain refinement in materials has been one of the most common strategies for improving the strength of materials. However this comes at the price of reduced ductility, fracture toughness and stable fatigue crack propagation ...

Singh, Aparna, Ph.D. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

320

High cycle fatigue of polycrystalline silicon thin films in laboratory air  

E-Print Network (OSTI)

When subjected to alternating stresses, most materials degrade, e.g., suffer premature failure, due to a phenomenon known as fatigue. It is generally accepted that in brittle materials, such as ceramics, cyclic fatigue can only take place where there is some degree of toughening, implying that premature fatigue failure would not be expected in polycrystalline silicon where such toughening is absent. However, the fatigue failure of polysilicon is reported in the present work, based on tests on thirteen thin-film (2 µm thick) specimens cycled to failure in laboratory air (~25ºC, 30-50 % relative humidity), where damage accumulation and failure of the notched cantilever beams were monitored electrically during the test. Specimen lives ranged from about 10 seconds to 34 days (5 x 10 5 to 1 x 10 11 cycles) with the stress amplitude at failure being reduced to ~50 % of the low-cycle strength for lives in excess of 10 9 cycles.

C. L. Muhlstein; S. B. Brown; R. O. Ritchie

2000-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Residual stress relief due to fatigue in tetragonal lead zirconate titanate ceramics  

SciTech Connect

High energy synchrotron XRD was employed to determine the lattice strain {epsilon}{l_brace}111{r_brace}and diffraction peak intensity ratio R{l_brace}200{r_brace}in tetragonal PZT ceramics, both in the virgin poled state and after a bipolar fatigue experiment. It was shown that the occurrence of microstructural damage during fatigue was accompanied by a reduction in the gradient of the {epsilon}{l_brace}111{r_brace}-cos{sup 2} {psi} plot, indicating a reduction in the level of residual stress due to poling. In contrast, the fraction of oriented 90 Degree-Sign ferroelectric domains, quantified in terms of R{l_brace}200{r_brace}, was not affected significantly by fatigue. The change in residual stress due to fatigue is interpreted in terms of a change in the average elastic stiffness of the polycrystalline matrix due to the presence of inter-granular microcracks.

Hall, D. A.; Mori, T. [School of Materials, University of Manchester, Grosvenor St., Manchester M1 7HS (United Kingdom); Comyn, T. P. [Institute for Materials Research, Woodhouse Lane, University of Leeds, LS2 9JT (United Kingdom); Ringgaard, E. [Meggitt Sensing Systems, Hejreskovvej 18A, 3490 Kvistgaard (Denmark); Wright, J. P. [ESRF, 6 Rue Jules Horowitz, BP-220, 38043 Grenoble Cedex (France)

2013-07-14T23:59:59.000Z

322

Fatigue Behavior of Tough Fe-Based Bulk-Metallic Glasses  

Science Conference Proceedings (OSTI)

A Fracture Mechanics Model of Fatigue Crack Propagation in Bulk-Metallic ... Air- Oxidation of a (Zr55Cu30Al10Ni5)98Er2 Bulk Metallic Glass at 350-500oc.

323

Creep-fatigue of High Temperature Materials for VHTR: Effect of Cyclic Loading and Environment  

SciTech Connect

Alloy 617 is the one of the leading candidate materials for Intermediate Heat eXchangers (IHX) of a Very High Temperature Reactor (VHTR). System start-ups and shut-downs as well as power transients will produce low cycle fatigue (LCF) loadings of components. Furthermore, the anticipated IHX operating temperature, up to 950°C, is in the range of creep so that creep-fatigue interaction, which can significantly increase the fatigue crack growth, may be one of the primary IHX damage modes. To address the needs for Alloy 617 codification and licensing, a significant creep-fatigue testing program is underway at Idaho National Laboratory. Strain controlled LCF tests including hold times up to 1800s at maximum tensile strain were conducted at total strain range of 0.3% and 0.6% in air at 950°C. Creep-fatigue testing was also performed in a simulated VHTR impure helium coolant for selected experimental conditions. The creep-fatigue tests resulted in failure times up to 1000 hrs. Fatigue resistance was significantly decreased when a hold time was added at peak stress and when the total strain was increased. The fracture mode also changed from transgranular to intergranular with introduction of a tensile hold. Changes in the microstructure were methodically characterized. A combined effect of temperature, cyclic and static loading and environment was evidenced in the targeted operating conditions of the IHX. This paper This paper reviews the data previously published by Carroll and co-workers in references 10 and 11 focusing on the role of inelastic strain accumulation and of oxidation in the initiation and propagation of surface fatigue cracks.

Celine Cabet; L. Carroll; R. Wright; R. Madland

2011-05-01T23:59:59.000Z

324

McKinsey Carbon Supply Curves | Open Energy Information  

Open Energy Info (EERE)

form form View source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit with form History Facebook icon Twitter icon » McKinsey Carbon Supply Curves Jump to: navigation, search Tool Summary LAUNCH TOOL Name: McKinsey Carbon Supply Curves Agency/Company /Organization: McKinsey and Company Sector: Energy, Land Topics: GHG inventory, Resource assessment, Pathways analysis, Background analysis Website: www.mckinsey.com/clientservice/ccsi/ References: McKinsey Climate Change Special Initiative[1] "The transition to a low-carbon economy represents one of the key challenges facing leaders in the early 21st century. Our Climate Change Special Initiative is a cross-functional and cross-industry effort, which

325

Load transfer coupling regression curve fitting for distribution load forecasting  

SciTech Connect

The planning of distribution facilities requires forecasts of future substation and feeder loads. Extrapolation based on a curve fit to past annual peak loads is currently the most popular manner of accomplishing this forecast. Curve fitting suffers badly from data shifts caused by switching as loads are routinely moved from one substation to another during the course of utility operations. This switching contaminates the data, reducing forecast accuracy. A new regression application reduces error due to these transfers by over an order of magnitude. A key to the usefulness of this method is that the amount of the transfer, and its direction (whether it was to or from a substation), is not a required input. The new technique, aspects of computer implementation of it, and a series of tests showing its advantage over normal multiple regression methods are given.

Willis, H.L.; Powell, R.W.

1984-05-01T23:59:59.000Z

326

Modeling software artifact count attribute with s-curves  

E-Print Network (OSTI)

The estimation of software project attributes, such as size, is important for software project resource planning and process control. However, research regarding software attribute modeling, such as size, effort, and cost, are high-level and static in nature. This research defines a new operation-level software project attribute that describes the operational characteristic of a software project. The result is a measurement based on the s-curve parameter that can be used as a control variable for software project management. This result is derived from modeling the count of artifact instances created by the software engineering process, which are stored by software tools. Because of the orthogonal origin of this attribute in regard to traditional static estimators, this s-curve based software attribute can function as an additional indicator of software project activities and also as a quantitative metric for assessing development team capability.

Ma, Norman K.

2007-12-01T23:59:59.000Z

327

Fast B-spline Curve Fitting by L-BFGS  

E-Print Network (OSTI)

We propose a novel method for fitting planar B-spline curves to unorganized data points. In traditional methods, optimization of control points and foot points are performed in two very time-consuming steps in each iteration: 1) control points are updated by setting up and solving a linear system of equations; and 2) foot points are computed by projecting each data point onto a B-spline curve. Our method uses the L-BFGS optimization method to optimize control points and foot points simultaneously and therefore it does not need to perform either matrix computation or foot point projection in every iteration. As a result, our method is much faster than existing methods.

Zheng, Wenni; Liu, Yang; Wang, Wenping

2012-01-01T23:59:59.000Z

328

Nonparametric inference of quantile curves for nonstationary time series  

E-Print Network (OSTI)

The paper considers nonparametric specification tests of quantile curves for a general class of nonstationary processes. Using Bahadur representation and Gaussian approximation results for nonstationary time series, simultaneous confidence bands and integrated squared difference tests are proposed to test various parametric forms of the quantile curves with asymptotically correct type I error rates. A wild bootstrap procedure is implemented to alleviate the problem of slow convergence of the asymptotic results. In particular, our results can be used to test the trends of extremes of climate variables, an important problem in understanding climate change. Our methodology is applied to the analysis of the maximum speed of tropical cyclone winds. It was found that an inhomogeneous upward trend for cyclone wind speeds is pronounced at high quantile values. However, there is no trend in the mean lifetime-maximum wind speed. This example shows the effectiveness of the quantile regression technique.

Zhou, Zhou

2010-01-01T23:59:59.000Z

329

Motor System Energy Efficiency Supply Curves: A Methodology for Assessing  

NLE Websites -- All DOE Office Websites (Extended Search)

Motor System Energy Efficiency Supply Curves: A Methodology for Assessing Motor System Energy Efficiency Supply Curves: A Methodology for Assessing the Energy Efficiency Potential of Industrial Motor Systems Speaker(s): Ali Hasanbeigi Date: February 8, 2011 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Aimee McKane Motor-driven equipment accounts for approximately 60% of manufacturing final electricity use worldwide. A major barrier to effective policymaking, and to more global acceptance of the energy efficiency potential in industrial motor systems, is the lack of a transparent methodology for quantifying the magnitude and cost-effectiveness of these energy savings. This paper presents the results of groundbreaking analyses conducted for five countries and one region to begin to address this barrier. Using a combination of expert opinion and available data from the United States,

330

EARLY SUPERNOVAE LIGHT CURVES FOLLOWING THE SHOCK BREAKOUT  

Science Conference Proceedings (OSTI)

The first light from a supernova (SN) emerges once the SN shock breaks out of the stellar surface. The first light, typically a UV or X-ray flash, is followed by a broken power-law decay of the luminosity generated by radiation that leaks out of the expanding gas sphere. Motivated by recent detection of emission from very early stages of several SNe, we revisit the theory of shock breakout and the following emission, paying special attention to the photon-gas coupling and deviations from thermal equilibrium. We derive simple analytic light curves of SNe from various progenitors at early times. We find that for more compact progenitors, white dwarfs, Wolf-Rayet stars (WRs), and possibly more energetic blue-supergiant explosions, the observed radiation is out of thermal equilibrium at the breakout, during the planar phase (i.e., before the expanding gas doubles its radius), and during the early spherical phase. Therefore, during these phases we predict significantly higher temperatures than previous analysis that assumed equilibrium. When thermal equilibrium prevails, we find the location of the thermalization depth and its temporal evolution. Our results are useful for interpretation of early SN light curves. Some examples are (1) red supergiant SNe have an early bright peak in optical and UV flux, less than an hour after breakout. It is followed by a minimum at the end of the planar phase (about 10 hr), before it peaks again once the temperature drops to the observed frequency range. In contrast, WRs show only the latter peak in optical and UV. (2) Bright X-ray flares are expected from all core-collapse SNe types. (3) The light curve and spectrum of the initial breakout pulse hold information on the explosion geometry and progenitor wind opacity. Its spectrum in more compact progenitors shows a (nonthermal) power law and its light curve may reveal both the breakout diffusion time and the progenitor radius.

Nakar, Ehud [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Sari, Re'em [Racah Institute for Physics, Hebrew University, Jerusalem 91904 (Israel)

2010-12-10T23:59:59.000Z

331

Forecasting technology costs via the Learning Curve - Myth or Magic?  

E-Print Network (OSTI)

is generally considered to be traditional fossil fuel power stations, hence making a further assumption that such a value for cost can be forecasted). In situations where niche markets exist (for example solar PV electricity for remote areas or hand held... Solar PV provides a good example of the use and dangers of using experience curves to forecast future costs of an energy technology. It is a good example since solar PV modules are generally accessed by an international market allowing for worldwide...

Alberth, Stephan

332

Motor Systems Efficiency Supply Curves | Open Energy Information  

Open Energy Info (EERE)

Motor Systems Efficiency Supply Curves Motor Systems Efficiency Supply Curves Jump to: navigation, search Tool Summary Name: Motor Systems Efficiency Supply Curves Agency/Company /Organization: United Nations Industrial Development Organization Sector: Energy Focus Area: Energy Efficiency, Industry Topics: Technology characterizations Resource Type: Publications, Case studies/examples Website: www.unido.org/fileadmin/user_media/Services/Energy_and_Climate_Change/ Country: United States, Canada, Thailand, Vietnam, Brazil UN Region: South-Eastern Asia, "Latin America and Caribbean" is not in the list of possible values (Eastern Africa, Middle Africa, Northern Africa, Southern Africa, Western Africa, Caribbean, Central America, South America, Northern America, Central Asia, Eastern Asia, Southern Asia, South-Eastern Asia, Western Asia, Eastern Europe, Northern Europe, Southern Europe, Western Europe, Australia and New Zealand, Melanesia, Micronesia, Polynesia, Latin America and the Caribbean) for this property., Northern America, "Western & Eastern Europe" is not in the list of possible values (Eastern Africa, Middle Africa, Northern Africa, Southern Africa, Western Africa, Caribbean, Central America, South America, Northern America, Central Asia, Eastern Asia, Southern Asia, South-Eastern Asia, Western Asia, Eastern Europe, Northern Europe, Southern Europe, Western Europe, Australia and New Zealand, Melanesia, Micronesia, Polynesia, Latin America and the Caribbean) for this property.

333

Indonesia Greenhouse Gas Abatement Cost Curve | Open Energy Information  

Open Energy Info (EERE)

Indonesia Greenhouse Gas Abatement Cost Curve Indonesia Greenhouse Gas Abatement Cost Curve Jump to: navigation, search Tool Summary Name: Indonesia Greenhouse Gas Abatement Cost Curve Agency/Company /Organization: Government of Indonesia Topics: Baseline projection, GHG inventory, Co-benefits assessment, Background analysis Resource Type: Software/modeling tools Website: www.dnpi.go.id/report/DNPI-Media-Kit/reports/indonesia-ghg_abatement_c Country: Indonesia UN Region: South-Eastern Asia Coordinates: -0.789275°, 113.921327° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":-0.789275,"lon":113.921327,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

334

Meta-design: design for designers  

Science Conference Proceedings (OSTI)

One fundamental challenge for the design of the interactive systems of the future is to invent and design environments and cultures in which humans can express themselves and engage in personally meaningful activities. Unfortunately, a large number of ... Keywords: consumer and designer mindsets, designing “out of the box”, domain-oriented design environments, evolutionary growth, impact of new media on design, open evolvable systems, open source, reseeding model, seeding, underdesigned systems

Gerhard Fischer; Eric Scharff

2000-08-01T23:59:59.000Z

335

BWRVIP-196: BWR Vessel and Internals Project, Assessment of Mixing Tee Thermal Fatigue Susceptibility in BWR Plants  

Science Conference Proceedings (OSTI)

In 1998, a French pressurized water reactor (PWR) plant experienced leakage due to thermal fatigue from piping immediately downstream of a residual heat removal (RHR) heat exchanger. EPRI report 1013305, Materials Reliability Program: Assessment of RHR Mixing Tee Thermal Fatigue in PWR Plants (MRP-192), December 2006, was prepared so that owners of PWR plants could determine if their RHR piping systems might be susceptible to similar thermal fatigue cracking and if additional inspection should be recomme...

2008-09-23T23:59:59.000Z

336

Final Report on Round-Robin Conducted in Support of Standard Test Method for Creep-Fatigue Testing  

Science Conference Proceedings (OSTI)

With the increased flexible operation of power plants, many components may now be subject to creep-fatigue damage mechanisms. This report covers the findings from a round-robin test program facilitated by the Electric Power Research Institute (EPRI) with broad international participation. The overall goal was to support the development of a new industry standard for addressing creep-fatigue crack initiation.BackgroundCreep-fatigue is a complex material ...

2013-07-31T23:59:59.000Z

337

Evaluation of Waterwall Corrosion Fatigue, Volume 2: Roadmap Case Study: Evaluation of AEP's Big Sandy Unit 1  

Science Conference Proceedings (OSTI)

As we continue to operate an ever-aging fleet of power plants, we experience increased boiler tube failures from failure mechanisms related to aging. One such failure mechanism is corrosion fatigue. Corrosion fatigue may result in failures in any water-touched surface in boilers and has been found in waterwalls, risers, and supply tubing, and drums. This report provides detailed research on the causes and actions to address corrosion fatigue in boiler waterwall tubing.

2011-05-31T23:59:59.000Z

338

Determination of the R-curve from the strength-indentation load relation  

SciTech Connect

Strength as a function of indentation load has been measured to evaluate toughness versus crack size curves (i.e., R-curves) of ceramics. In the past, this evaluation is achieved by generating a family of global stress intensity versus crack size curves (i.e., K-curves) at each indentation load and its corresponding strength, and then fitting an envelope of tangency points to these curves. This envelope yields the R-curve. A methodology is proposed in the present study to define the point in the K-curve at which the R-curve intersects. This methodology complements the conventional ``tangency condition`` approach in determining the R-curve from the experimental strength-indentation load relation.

Hsueh, C.H.; Becher, P.F. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Division

1995-08-01T23:59:59.000Z

339

Goal 4 Long Life Pavement Rehabilitation Strategies-Rigid: Flexural Fatigue Life of Hydraulic Cement Concrete Beams  

E-Print Network (OSTI)

Flexural Fatigue Life of Hydraulic Cement Concrete Beamsperformance of Fast-Setting Hydraulic Cement Concrete (and Thermal Expansion of Hydraulic Cement Concrete Mixes”,

Kohler, Erwin R.; Ali, Abdikarim; Harvey, John T

2005-01-01T23:59:59.000Z

340

Effect of Creep and Oxidation on Reduced Creep-Fatigue life of Ni-based Alloy 617 at 850 C  

SciTech Connect

Low cycle fatigue (LCF) and creep fatigue testing of Ni-based alloy 617 was carried out at 850 C. Compared with its LCF life, the material s creep fatigue life decreases to different extents depending on test conditions. To elucidate the microstructure-fatigue property relationship for alloy 617 and the effect of creep and oxidation on its fatigue life, systematic microstructural investigations were carried out using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electron backscatter diffraction (EBSD). In LCF tests, as the total strain range increased, deformations concentrated near high angle grain boundaries (HAGBs). The strain hold period in the creep fatigue tests introduced additional creep damage to the material, which revealed the detrimental effect of the strain hold time on the material fatigue life in two ways. First, the strain hold time enhanced the localized deformation near HAGBs, resulting in the promotion of intergranular cracking of alloy 617. Second, the strain hold time encouraged grain boundary sliding, which resulted in interior intergranular cracking of the material. Oxidation accelerated the initiation of intergranular cracking in alloy 617. In the crack propagation stage, if oxidation was promoted and the cyclic oxidation damage was greater than the fatigue damage, oxidation-assisted intergranular crack growth resulted in a significant reduction in the material s fatigue life.

Chen, Xiang [ORNL] [ORNL; Yang, Zhiqing [ORNL] [ORNL; Sokolov, Mikhail A [ORNL] [ORNL; ERDMAN III, DONALD L [ORNL] [ORNL; Mo, Kun [ORNL] [ORNL; Stubbins, James [ORNL] [ORNL

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Positive design  

Science Conference Proceedings (OSTI)

This article is focused on the changes needed in design to create positive solutions for all involved in design processes. It draws upon the rich discussion and discourse from a conference focused on positive design involving managers, designers, and ...

Jurgen Faust

2009-09-01T23:59:59.000Z

342

NREL: Computational Science - Inverse Design  

NLE Websites -- All DOE Office Websites (Extended Search)

Inverse Design Inverse Design The NREL Computational Science Center collaborates with the High Throughput and Inverse Band Structure (HT/IBS) Group within the Center for Inverse Design (CID) to research, design, and create materials with given target properties. The Center for Inverse Design is an Energy Frontier Research Center of the U.S. Department of Energy Office of Science. To address a crucial scientific grand challenge, the Center is pursuing a new approach to material science. Rather than using the conventional direct approach ("Given the structure, find the electronic properties"), we are using a "materials by inverse design" approach ("Given the desired property, find the structure"). Illustration of a blue arrow pointing to a graphic with three curved lines that represent an electronic structure and blue arrow pointing to a red and blue balls that represent an atomic configuration.

343

Average Soil Water Retention Curves Measured by Neutron Radiography  

SciTech Connect

Water retention curves are essential for understanding the hydrologic behavior of partially-saturated porous media and modeling flow transport processes within the vadose zone. In this paper we report direct measurements of the main drying and wetting branches of the average water retention function obtained using 2-dimensional neutron radiography. Flint sand columns were saturated with water and then drained under quasi-equilibrium conditions using a hanging water column setup. Digital images (2048 x 2048 pixels) of the transmitted flux of neutrons were acquired at each imposed matric potential (~10-15 matric potential values per experiment) at the NCNR BT-2 neutron imaging beam line. Volumetric water contents were calculated on a pixel by pixel basis using Beer-Lambert s law after taking into account beam hardening and geometric corrections. To remove scattering effects at high water contents the volumetric water contents were normalized (to give relative saturations) by dividing the drying and wetting sequences of images by the images obtained at saturation and satiation, respectively. The resulting pixel values were then averaged and combined with information on the imposed basal matric potentials to give average water retention curves. The average relative saturations obtained by neutron radiography showed an approximate one-to-one relationship with the average values measured volumetrically using the hanging water column setup. There were no significant differences (at p < 0.05) between the parameters of the van Genuchten equation fitted to the average neutron radiography data and those estimated from replicated hanging water column data. Our results indicate that neutron imaging is a very effective tool for quantifying the average water retention curve.

Cheng, Chu-Lin [ORNL; Perfect, Edmund [University of Tennessee, Knoxville (UTK); Kang, Misun [ORNL; Voisin, Sophie [ORNL; Bilheux, Hassina Z [ORNL; Horita, Juske [Texas Tech University (TTU); Hussey, Dan [NIST Center for Neutron Research (NCRN), Gaithersburg, MD

2011-01-01T23:59:59.000Z

344

Moisture Retention Curves of Topopah Spring Tuff at Elevated Temperatures  

SciTech Connect

Knowledge of unsaturated flow and transport in porous media is critical for understanding the movement of water and solute through the unsaturated zone. The suction potential of rock determines the imbibition of water and, therefore, the moisture retention in the matrix. That, in turn, affects the relative importance of matrix flow and fracture flow, and their interaction, because greater suction potential moves more water from fractures into the matrix and therefore retards fracture flow. The moisture content as a function of the suction potential is called a moisture retention curve or a characteristic curve. Moisture-retention data are important input for numerical models of water movement in unsaturated porous media. Also important are the effect of sample history on the moisture-retention curves and whether there is significant hysteresis between wetting and drying measurements. The Yucca Mountain Site Characterization Project (YMP) of the U.S. Department of Energy is studying the suitability of the tuffaceous rock at Yucca Mountain, Nevada, for a potential high-level nuclear waste repository. The potential repository horizon will be in the unsaturated zone of the Topopah Spring member (densely welded) of the Paintbrush Tuff unit at Yucca Mountain. This unit is highly fractured. Therefore, transport of water within the near field of the nuclear waste package in the repository is strongly influenced by the suction potential of the repository host rocks at elevated temperatures. In a high-level nuclear waste repository, the rock mass around the waste packages will become dry because of the thermal load of the waste but will then re-wet during the cool-down period as the thermal output of the waste packages declines. Much of this process will occur at temperatures above ambient temperature. The goal of our work is to determine the importance of temperature and the wetting-drying hysteresis on the measured moisture retention curves of the densely welded tuff. For Topopah Spring tuff the suction potential is assumed to be primary due to the matric potential.

Lin, W.; Roberts, J.; Carlberg, E.; Ruddle, D.; Pletcher, R.

2001-11-30T23:59:59.000Z

345

Electricity Price Curve Modeling and Forecasting by Manifold Learning  

E-Print Network (OSTI)

This paper proposes a novel nonparametric approach for the modeling and analysis of electricity price curves by applying the manifold learning methodology—locally linear embedding (LLE). The prediction method based on manifold learning and reconstruction is employed to make short-term and mediumterm price forecasts. Our method not only performs accurately in forecasting one-day-ahead prices, but also has a great advantage in predicting one-week-ahead and one-month-ahead prices over other methods. The forecast accuracy is demonstrated by numerical results using historical price data taken from the Eastern U.S. electric power markets.

Jie Chen; Shi-Jie Deng; Xiaoming Huo

2008-01-01T23:59:59.000Z

346

FPGA curved track fitter with very low resource usage  

SciTech Connect

Standard least-squares curved track fitting process is tailored for FPGA implementation. The coefficients in the fitting matrices are carefully chosen so that only shift and accumulation operations are used in the process. The divisions and full multiplications are eliminated. Comparison in an application example shows that the fitting errors of the low resource usage implementation are less than 4% bigger than the fitting errors of the exact least-squares algorithm. The implementation is suitable for low-cost, low-power applications such as high energy physics detector trigger systems.

Wu, Jin-Yuan; Wang, M.; Gottschalk, E.; Shi, Z.; /Fermilab

2006-11-01T23:59:59.000Z

347

Approximating RR Lyrae light curves using cubic polynomials  

E-Print Network (OSTI)

In this paper, we use cubic polynomials to approximate RR Lyrae light curves and apply the method to HST data of RR Lyraes in the halo of M31. We compare our method to the standard method of Fourier decomposition and find that the method of cubic polynomials eliminates virtually all ringing effects and does so with significantly fewer parameters than the Fourier technique. Further, for RRc stars the parameters in the fit are all physical. Our study also reveals a number of additional periodicites in this data not found previously: we find 23 RRc stars, 29 RRab stars and 3 multiperiodic stars.

Reyner, Steven; Ngeow, C; Morgan, C

2010-01-01T23:59:59.000Z

348

Information Geometry and Chaos on Negatively Curved Statistical Manifolds  

E-Print Network (OSTI)

A novel information-geometric approach to chaotic dynamics on curved statistical manifolds based on Entropic Dynamics (ED) is suggested. Furthermore, an information-geometric analogue of the Zurek-Paz quantum chaos criterion is proposed. It is shown that the hyperbolicity of a non-maximally symmetric 6N-dimensional statistical manifold M_{s} underlying an ED Gaussian model describing an arbitrary system of 3N non-interacting degrees of freedom leads to linear information-geometric entropy growth and to exponential divergence of the Jacobi vector field intensity, quantum and classical features of chaos respectively.

Carlo Cafaro

2008-10-25T23:59:59.000Z

349

Robust entrainment of circadian oscillators requires specific phase response curves  

E-Print Network (OSTI)

tool based on this rendering method. Our interactive tangible daylighting design system can be used by novice or experienced designers who need not be experts in daylighting technology or advanced graphical heliodon system [42], [43] that complements modern desktop architectural daylighting design software tools

Paris-Sud XI, Université de

350

Novel Experiments to Characterize Creep-Fatigue Degradation in VHTR Alloys  

SciTech Connect

It is well known in energy systems that the creep lifetime of high temperature alloys is significantly degraded when a cyclic load is superimposed on components operating in the creep regime. A test method has been developed in an attempt to characterize creep-fatigue behavior of alloys at high temperature. The test imposes a hold time during the tensile phase of a fully reversed strain-controlled low cycle fatigue test. Stress relaxation occurs during the strain-controlled hold period. This type of fatigue stress relaxation test tends to emphasize the fatigue portion of the total damage and does not necessarily represent the behavior of a component in-service well. Several different approaches to laboratory testing of creep-fatigue at 950°C have been investigated for Alloy 617, the primary candidate for application in VHTR heat exchangers. The potential for mode switching in a cyclic test from strain control to load control, to allow specimen extension by creep, has been investigated to further emphasize the creep damage. In addition, tests with a lower strain rate during loading have been conducted to examine the influence of creep damage occurring during loading. Very short constant strain hold time tests have also been conducted to examine the influence of the rapid stress relaxation that occurs at the beginning of strain holds.

J. K. Wright; J. A. Simpson; L. J. Carroll; R. N. Wright; T.-L. Sham

2013-10-01T23:59:59.000Z

351

An analytical study of rail grinding optimization for rail-head fatigue defect prevention  

E-Print Network (OSTI)

Over the last two decades, the railroad industry has experienced a significant increase in heavy axle loads acting on railroad rails. In addition, railroad operations have been consolidated resulting in the elimination of redundant routes and increased train traffic on the remaining routes. These changes in railroad industry practice have caused an increase in the rate of occurrence of rail head fatigue defects, one potential cause of train derailment. The primary form of maintenance employed by the individual railroads to combat the formation of fatigue defects is rail grinding. Current rail grinding practices involve removal of surface defects and reshaping worn rail, but they do not involve grinding as a means to mitigate internal fatigue damage. In this study, a model for optimizing a grinding schedule which will prevent the formation of internal fatigue defects is proposed. The model includes a statistical representation of wheel loads, a rail head stress analysis, a rail head fatigue analysis, and optimization of a grinding schedule via mathematical programming. Results from using this model indicate that rail grinding might be performed in such a way as to double the useful service life of railroad rail.

Jones, Scott Laurence

1997-01-01T23:59:59.000Z

352

2008. Approximating learning curves for active-learning-driven annotation  

E-Print Network (OSTI)

Active learning (AL) is getting more and more popular as a methodology to considerably reduce the annotation effort when building training material for statistical learning methods for various NLP tasks. A crucial issue rarely addressed, however, is when to actually stop the annotation process to profit from the savings in efforts. This question is tightly related to estimating the classifier performance after a certain amount of data has already been annotated. While learning curves are the default means to monitor the progress of the annotation process in terms of classifier performance, this requires a labeled gold standard which – in realistic annotation settings, at least – is often unavailable. We here propose a method for committee-based AL to approximate the progression of the learning curve based on the disagreement among the committee members. This method relies on a separate, unlabeled corpus and is thus well suited for situations where a labeled gold standard is not available or would be too expensive to obtain. Considering named entity recognition as a test case we provide empirical evidence that this approach works well under simulation as well as under real-world annotation conditions. 1.

Katrin Tomanek; Udo Hahn

2008-01-01T23:59:59.000Z

353

Controlling adsorption of semiflexible polymers on planar and curved substrates  

E-Print Network (OSTI)

We study the adsorption of semiflexible polymers such as polyelectrolytes or DNA on planar and curved substrates, e.g., spheres or washboard substrates via short-range potentials using extensive Monte-Carlo simulations, scaling arguments, and analytical transfer matrix techniques. We show that the adsorption threshold of stiff or semiflexible polymers on a planar substrate can be controlled by polymer stiffness: adsorption requires the highest potential strength if the persistence length of the polymer matches the range of the adsorption potential. On curved substrates, i.e., an adsorbing sphere or an adsorbing washboard surface, the adsorption can be additionally controlled by the curvature of the surface structure. The additional bending energy in the adsorbed state leads to an increase of the critical adsorption strength, which depends on the curvature radii of the substrate structure. For an adsorbing sphere, this gives rise to an optimal polymer stiffness for adsorption, i.e., a local minimum in the critical potential strength for adsorption, which can be controlled by curvature. For two- and three-dimensional washboard substrates, we identify the range of persistence lengths and the mechanisms for an effective control of the adsorption threshold by the substrate curvature.

Tobias A. Kampmann; Horst-Holger Boltz; Jan Kierfeld

2013-06-20T23:59:59.000Z

354

Extremum seeking control techniques applied to photovoltaic systems with multimodal power curves  

E-Print Network (OSTI)

) Current(A) 0 200 320025 I-V curve P-V curve VMPP Power(W) 1000 Fig. 1. Photovoltaic cell I-V and P generator method, open-circuit voltage photovoltaic cell test method, incremental conductance method (CI) [5Extremum seeking control techniques applied to photovoltaic systems with multimodal power curves

Recanati, Catherine

355

Some new results on non-rigid correspondence and classification of curves  

Science Conference Proceedings (OSTI)

We present two new algorithms for correspondence and classification of planar curves in a non-rigid sense. In the first algorithm we define deforming energy based on aligning curves using certain of their properties, namely Multi-Step-Size Local Similarity ... Keywords: correspondence, curve alignment, dynamic programming, recognition

Xiqiang Zheng; Yunmei Chen; David Groisser; David Wilson

2005-11-01T23:59:59.000Z

356

REMARKS ON THE PARABOLIC CURVES ON SURFACES AND ON THE MANYDIMENSIONAL M  

E-Print Network (OSTI)

REMARKS ON THE PARABOLIC CURVES ON SURFACES AND ON THE MANY­DIMENSIONAL M ¨ OBIUS--STURM THEORY V. I. Arnold V. A. Steklov Mathematical Institute August 26, 1997 Conjecture on Four Parabolic Curves of several variables) show that natural analogs of inflection points are parabolic curves of surfaces

Arnold, Vladimir Igorevich

357

A simple method of estimating wind turbine blade fatigue at potential wind turbine sites  

SciTech Connect

This paper presents a technique of estimating blade fatigue damage at potential wind turbine sites. The cornerstone of this technique is a simple model for the blade`s root flap bending moment. The model requires as input a simple set of wind measurements which may be obtained as part of a routine site characterization study. By using the model to simulate a time series of the root flap bending moment, fatigue damage rates may be estimated. The technique is evaluated by comparing these estimates with damage estimates derived from actual bending moment data; the agreement between the two is quite good. The simple connection between wind measurements and fatigue provided by the model now allows one to readily discriminate between damaging and more benign wind environments.

Barnard, J.C.; Wendell, L.L.

1995-06-01T23:59:59.000Z

358

Atmospheric and Wake Turbulence Impacts on Wind Turbine Fatigue Loading: Preprint  

DOE Green Energy (OSTI)

Large-eddy simulations of atmospheric boundary layers under various stability and surface roughness conditions are performed to investigate the turbulence impact on wind turbines. In particular, the aeroelastic responses of the turbines are studied to characterize the fatigue loading of the turbulence present in the boundary layer and in the wake of the turbines. Two utility-scale 5 MW turbines that are separated by seven rotor diameters are placed in a 3 km by 3 km by 1 km domain. They are subjected to atmospheric turbulent boundary layer flow and data is collected on the structural response of the turbine components. The surface roughness was found to increase the fatigue loads while the atmospheric instability had a small influence. Furthermore, the downstream turbines yielded higher fatigue loads indicating that the turbulent wakes generated from the upstream turbines have significant impact.

Lee, S.; Churchfield, M.; Moriarty, P.; Jonkman, J.; Michalakes, J.

2011-12-01T23:59:59.000Z

359

Estimation of fatigue and extreme load distributions from limited data with application to wind energy systems.  

SciTech Connect

An estimate of the distribution of fatigue ranges or extreme loads for wind turbines may be obtained by separating the problem into two uncoupled parts, (1) a turbine specific portion, independent of the site and (2) a site-specific description of environmental variables. We consider contextually appropriate probability models to describe the turbine specific response for extreme loads or fatigue. The site-specific portion is described by a joint probability distribution of a vector of environmental variables, which characterize the wind process at the hub-height of the wind turbine. Several approaches are considered for combining the two portions to obtain an estimate of the extreme load, e.g., 50-year loads or fatigue damage. We assess the efficacy of these models to obtain accurate estimates, including various levels of epistemic uncertainty, of the turbine response.

Fitzwater, LeRoy M. (Stanford University, Stanford, CA)

2004-01-01T23:59:59.000Z

360

Fatigue resistance and microstructure of experimental dual phase Fe/2Si/0. 1C steel  

Science Conference Proceedings (OSTI)

The fatigue behavior of an experimental dual phase Fe/2Si/0.1C steel has been examined as a function of constituent morphology with the objective of developing ferritic-martensitic microstructures with optimum strength and fatigue crack propagation resistance. Microstructure containing fine globular or coarse martensite within a coarse-grained ferritic matrix were found to show the highest fatigue threshold stress intensity range ..delta..K/sub o/ values reported to date (to our knowledge) and certainly the highest combination of strength and ..delta..K/sub o/ for steels (..delta..K/sub o/ values above 19 MPa..sqrt..m with yield strengths in excess of 600 MPa). Such unusually high crack growth resistance is attributed primarily to a meandering crack path morphology which promotes slower crack extension rates from crack deflection and roughness-induced crack closure mechanisms.

Dutta, V.B.; Suresh, S.; Thomas, G.; Ritchie, R.O.

1983-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Photon Green Functions in Curved Space-Time  

E-Print Network (OSTI)

Quantization of electrodynamics in curved space-time in the Lorenz gauge and with arbitrary gauge parameter makes it necessary to study Green functions of non-minimal operators with variable coefficients. Starting from the integral representation of photon Green functions, we link them to the evaluation of integrals involving Gamma-functions. Eventually, the full asymptotic expansion of the Feynman photon Green function at small values of the world function, as well as its explicit dependence on the gauge parameter, are obtained without adding by hand a mass term to the Faddeev-Popov Lagrangian. Coincidence limits of second covariant derivatives of the associated Hadamard function are also evaluated, as a first step towards the energy-momentum tensor in the non-minimal case.

Giuseppe Bimonte; Enrico Calloni; Luciano Di Fiore; Giampiero Esposito; Leopoldo Milano; Luigi Rosa

2005-11-23T23:59:59.000Z

362

Equilibrium spherically curved 2D Lennard-Jones systems  

E-Print Network (OSTI)

To learn about basic aspects of nano-scale spherical molecular shells during their formation, spherically curved two-dimensional N-particle Lennard-Jones systems are simulated, studying curvature evolution paths at zero-temperature. For many N-values (N<800) equilibrium configurations are traced as a function of the curvature radius R. Sharp jumps for tiny changes in R between trajectories with major differences in topological structure correspond to avalanche-like transitions. For a typical case, N=25, equilibrium configurations fall on smooth trajectories in state space which can be traced in the E-R plane. The trajectories show-up with local energy minima, from which growth in N at steady curvature can develop.

J. M. Voogd; P. M. A. Sloot; R. van Dantzig

2005-07-06T23:59:59.000Z

363

Graphene: QFT in curved spacetimes close to experiments  

E-Print Network (OSTI)

A recently proposed step-by-step procedure, to merge the low-energy physics of the $\\pi$-bonds electrons of graphene, and quantum field theory on curved spacetimes, is recalled. The last step there is the proposal of an experiment to test a Hawking-Unruh effect, emerging from the model, that manifests itself as an exact (within the model) prediction for the electronic local density of states, in the ideal case of the graphene membrane shaped as a Beltrami pseudosphere. A discussion about one particular attempt to experimentally test the model on molecular graphene is presented, and it is taken as an excuse to solve some basic issues that will help future experiments. In particular, it is stated that the effect should be visible on generic surfaces of constant negative Gaussian curvature, that are infinite in number.

Alfredo Iorio

2013-04-09T23:59:59.000Z

364

Simulation and Experiment of Thermal Fatigue in the CPV Die Attach: Preprint  

DOE Green Energy (OSTI)

FEM simulation and accelerated thermal cycling have been performed for the CPV die attach. Trends in fatigue damage accumulation and equivalent test time are explored and found to be most sensitive to temperature ramp rate. Die attach crack growth is measured through cycling and found to be in excellent agreement with simulations of the inelastic strain energy accumulated. Simulations of an entire year of weather data provides for the relative ranking of fatigue damage between four cites as well as their equivalent accelerated test time.

Bosco, N.; Silverman, T.; Kurtz, S.

2012-05-01T23:59:59.000Z

365

Fatigue analysis of WECS (Wind Energy Conversion System) components using a rainflow counting algorithm  

Science Conference Proceedings (OSTI)

A rainflow counting algorithm'' has been incorporated into the LIFE2 fatigue/fracture analysis code for wind turbines. The count algorithm, with its associated pre- and post-count algorithms, permits the code to incorporate time-series data into its analysis scheme. After a description of the algorithms used here, their use is illustrated by the examination of stress-time histories from the Sandia 34-m Test Bed vertical axis wind turbine. The results of the rainflow analysis are compared and contrasted to previously reported predictions for the service lifetime of the fatigue critical component for this turbine. 14 refs., 8 figs., 3 tabs.

Sutherland, H.J.; Schluter, L.L.

1990-01-01T23:59:59.000Z

366

The Effect of Tube Bend Geometry on the Development of Corrosion Fatigue Damage  

Science Conference Proceedings (OSTI)

Corrosion fatigue cracking in supply and riser tubing has occurred in a range of fossil plants. Tubing of this type can run outside the boiler so that, in some cases, the failures result in significant damage and risk for the safety of personnel. The overall EPRI effort in examining corrosion fatigue damage in supply and riser tube systems is aimed at the following: Developing a set of case studies in which the background is collated on plants exhibiting problems as well as plants where no significant da...

2011-06-30T23:59:59.000Z

367

One-Year Longitudinal Study of Fatigue, Cognitive Functions, and Quality of Life After Adjuvant Radiotherapy for Breast Cancer  

SciTech Connect

Purpose: Most patients with localized breast cancer (LBC) who take adjuvant chemotherapy (CT) complain of fatigue and a decrease in quality of life during or after radiotherapy (RT). The aim of this longitudinal study was to compare the impact of RT alone with that occurring after previous CT on quality of life. Methods and Materials: Fatigue (the main endpoint) and cognitive impairment were assessed in 161 CT-RT and 141 RT patients during RT and 1 year later. Fatigue was assessed with Functional Assessment of Cancer Therapy-General questionnaires, including breast and fatigue modules. Results: At baseline, 60% of the CT-RT patients expressed fatigue vs. 33% of the RT patients (p <0.001). Corresponding values at the end of RT were statistically similar (61% and 53%), and fatigue was still reported at 1 year by more than 40% of patients in both groups. Risk factors for long-term fatigue included depression (odds ratio [OR] = 6), which was less frequent in the RT group at baseline (16% vs. 28 %, respectively, p = 0.01) but reached a similar value at the end of RT (25% in both groups). Initial mild cognitive impairments were reported by RT (34 %) patients and CT-RT (24 %) patients and were persistent at 1 year for half of them. No biological disorders were associated with fatigue or cognitive impairment. Conclusions: Fatigue was the main symptom in LBC patients treated with RT, whether they received CT previously or not. The correlation of persistent fatigue with initial depressive status favors administering medical and psychological programs for LBC patients treated with CT and/or RT, to identify and manage this main quality-of-life-related symptom.

Noal, Sabine [Medical Oncology Department, Centre Francois Baclesse, Caen (France); Clinical Research Department, Centre Francois Baclesse, Caen (France); Levy, Christelle [Medical Oncology Department, Centre Francois Baclesse, Caen (France); Hardouin, Agnes [Department of Medical Biology, Centre Francois Baclesse, Caen (France); Rieux, Chantal [Clinical Research Department, Centre Francois Baclesse, Caen (France); Heutte, Natacha [Universite de Caen Basse Normandie GRECAN, Caen (France); Segura, Carine [Medical Oncology Department, Centre Francois Baclesse, Caen (France); Collet, Fabienne [Clinical Research Department, Centre Francois Baclesse, Caen (France); Allouache, Djelila; Switsers, Odile; Delcambre, Corinne; Delozier, Thierry [Medical Oncology Department, Centre Francois Baclesse, Caen (France); Henry-Amar, Michel [Clinical Research Department, Centre Francois Baclesse, Caen (France); Joly, Florence, E-mail: f.joly@baclesse.fr [Medical Oncology Department, Centre Francois Baclesse, Caen (France); Clinical Research Department, Centre Francois Baclesse, Caen (France); CHU, Cote de Nacre, Caen (France)

2011-11-01T23:59:59.000Z

368

Creep and Fatigue Interactions of Haynes 282 at Elevated ...  

Science Conference Proceedings (OSTI)

On Closed-Cell Aluminum Foam Used as Train Floor and Side Plate ... Piezoelectric Smart Composites: Electromechanical Properties and Design Maps

369

Atomistic modeling of nanowires, small-scale fatigue damage in cast magnesium, and materials for MEMS.  

Science Conference Proceedings (OSTI)

Lightweight and miniaturized weapon systems are driving the use of new materials in design such as microscale materials and ultra low-density metallic materials. Reliable design of future weapon components and systems demands a thorough understanding of the deformation modes in these materials that comprise the components and a robust methodology to predict their performance during service or storage. Traditional continuum models of material deformation and failure are not easily extended to these new materials unless microstructural characteristics are included in the formulation. For example, in LIGA Ni and Al-Si thin films, the physical size is on the order of microns, a scale approaching key microstructural features. For a new potential structural material, cast Mg offers a high stiffness-to-weight ratio, but the microstructural heterogeneity at various scales requires a structure-property continuum model. Processes occurring at the nanoscale and microscale develop certain structures that drive material behavior. The objective of the work presented in this report was to understand material characteristics in relation to mechanical properties at the nanoscale and microscale in these promising new material systems. Research was conducted primarily at the University of Colorado at Boulder to employ tightly coupled experimentation and simulation to study damage at various material size scales under monotonic and cyclic loading conditions. Experimental characterization of nano/micro damage will be accomplished by novel techniques such as in-situ environmental scanning electron microscopy (ESEM), 1 MeV transmission electron microscopy (TEM), and atomic force microscopy (AFM). New simulations to support experimental efforts will include modified embedded atom method (MEAM) atomistic simulations at the nanoscale and single crystal micromechanical finite element simulations. This report summarizes the major research and development accomplishments for the LDRD project titled 'Atomistic Modeling of Nanowires, Small-scale Fatigue Damage in Cast Magnesium, and Materials for MEMS'. This project supported a strategic partnership between Sandia National Laboratories and the University of Colorado at Boulder by providing funding for the lead author, Ken Gall, and his students, while he was a member of the University of Colorado faculty.

Dunn, Martin L. (University of Colorado, Boulder, CO); Talmage, Mellisa J. (University of Colorado, Boulder, CO); McDowell, David L., 1956- (,-Georgia Institute of Technology, Atlanta, GA); West, Neil (University of Colorado, Boulder, CO); Gullett, Philip Michael (Mississippi State University , MS); Miller, David C. (University of Colorado, Boulder, CO); Spark, Kevin (University of Colorado, Boulder, CO); Diao, Jiankuai (University of Colorado, Boulder, CO); Horstemeyer, Mark F. (Mississippi State University , MS); Zimmerman, Jonathan A.; Gall, K (Georgia Institute of Technology, Atlanta, GA)

2006-10-01T23:59:59.000Z

370

OTEC SKSS preliminary designs. Volume IV. Appendixes. Final report  

DOE Green Energy (OSTI)

This volume contains appendices to the Station Keeping Subsystem design study for the 40 MeW Modular Experiment OTEC platforms. Appendices presented include: detailed drag calculations; sample CALMS computer printouts for SPAR and BARGE static analyses; sample time domain computer printouts (Hydromechanics, Inc.) program; extreme value and fatigue load calculations; anchor design calculations; deployment calculations; bottom slope plots; time domain analysis report by Hydromechanics Inc.; detailed cost analysis; control systems study report by Sperry Systems Management; cost estimates for model basin tests; and hydrodynamic loading on the mooring cables. (WHK)

,

1980-02-29T23:59:59.000Z

371

Measurement of rising R-curve behavior in toughened silicon nitride by stable crack propagation in bending  

SciTech Connect

A simple procedure for measuring the R-curve properties of ceramics by a stable fracture test in three-point bending is described. As a typical case, data are displayed for a Si{sub 3}N{sub 4} material toughened by the presence of acicular grains in situ grown during the sintering process. The fracture mechanics specimen was a single-edge double-notched beam (SEDNB), whose notch was sharpened to a radius of < 10 {micro}m in order to reduce the amount of elastic energy stored at its root prior to crack extension. Furthermore, a stabilizer, specially designed for the bending geometry, was used to control crack stability. During stable extension, the crack could be easily arrested at selected locations of the load-displacement curve, the load quickly released, and the stable crack extension directly measured by the die-penetration technique. The crack resistance, K{sub R}, of the material was calculated from the measured crack extent and the onset load value before unloading. This method enabled them to precisely monitor the critical load value at which the load-displacement curve deviated from linear behavior, as well as crack extensions from a few tens of micrometers to about 1 mm. As an application of this method, the fracture resistance of a Si{sub 3}N{sub 4} material with rising R-curve behavior was measured and found to increase from about 5.5 to 9.0 MPa {center_dot} m{sup 1/2} within a 0.8-mm extension.

Nishida, Toshihiko; Hanaki, Yoshikazu [Kyoto Inst. of Tech. (Japan). Dept. of Materials; Nojima, Taketoshi [Kyoto Univ. (Japan). Dept. of Aeronautical Engineering; Pezzotti, G. [Toyohashi Univ. of Technology (Japan). Dept. of Materials Science

1995-11-01T23:59:59.000Z

372

A New Method To Predict Fatigue Crack Growth Life for the Armored Hull  

Science Conference Proceedings (OSTI)

Based on theories of dynamics of multi-body systems and linear elastic fracture mechanics, by using virtual prototyping technique, the model of tracked vehicle is established, and stress spectrums of the armored hull’s weak points are tested by ... Keywords: Virtual Prototyping, Virtual Test, Fatigue Crack Grow, Simulation

Wang Hongyan; Yang Tao; Shang Qigang

2010-11-01T23:59:59.000Z

373

Hold-Time Effects on Low-Cycle-Fatigue Behavior of Hastelloy® X ...  

Science Conference Proceedings (OSTI)

Total strain-controlled low-cycle-fatigue tests with and without hold times were ... frequency-modified tensile-hysteresis-energy method. The predicted lives were ... usage of this material in gas-turbine and chemical-process industries is based ...

374

Delamination of a sensitized commercial AlMg alloy during fatigue crack growth  

E-Print Network (OSTI)

as sensitization to corrosion and stress corrosion cracking [1,3,4,8], with exposure to tem- peratures between 50,9­12]. The presence and growth of b-phase have been shown to severely degrade the corrosion resistance and stressDelamination of a sensitized commercial Al­Mg alloy during fatigue crack growth J.K. Brosi and J

Rollins, Andrew M.

375

International Journal of Fatigue 21 (1999) 725731 www.elsevier.com/locate/ijfatigue  

E-Print Network (OSTI)

performance materials subject to severe operating conditions in the high temperature turbine section of gas fatigue crack propagation behavior of a nickel-base turbine disk alloy S.A. Padula II a , A. Shyam a , R turbine engines. Turbine blades in modern engines are fabricated from Ni-base alloy single crystals which

Ritchie, Robert

376

Interfacial delamination and fatigue life estimation of 3D solder bumps in flip-chip packages  

E-Print Network (OSTI)

fracture behaviors under thermal load. The 3D analysis also estimated thermal fatigue life of solder bumps, small profiles, and good electrical performance, area-array solder-bumped flip-chip technology-dimensional finite element analysis was carried out for area-array solder-bumped flip-chip packages. The analysis

Nakamura, Toshio

377

Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue  

E-Print Network (OSTI)

Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue Kyu Hun Kim-based foams10­14 and aero- gels15,16 . However, all nanotube-based foams and aerogels devel- oped so far10,11,13,14 when they are subjected to cyclic strain. Here, we show that an inelastic aerogel made

Islam, Mohammad F.

378

Understanding Microstructural Effects on Long Term Electrical Fatigue in Multilayer PZT Actuators*  

E-Print Network (OSTI)

and lower device degradation with usage time was observed. Keywords: lead zirconate titanate, PbTixZr1-xO3Understanding Microstructural Effects on Long Term Electrical Fatigue in Multilayer PZT Actuators to 1325 °C. Sintering times were 6 and 24 minutes. Samples were poled and additionally electrically

Balzar, Davor

379

Influence of Hold Time on Creep-Fatigue Behavior of an Advanced Austenitic Alloy  

Science Conference Proceedings (OSTI)

An advanced austenitic alloy, HT-UPS (high temperature-ultrafine precipitate strengthened), is a candidate material for the structural components of fast reactors and energy-conversion systems. HT-UPS provides improved creep resistance through a composition based on 316 stainless steel (SS) with additions of Ti and Nb to form nano-scale MC precipitates in the austenitic matrix. The low cycle fatigue and creep-fatigue behavior of a HT-UPS alloy has been investigated at 650 C, 1.0% total strain, and an R ratio of -1 with hold times as long as 9000 sec at peak tensile strain. The cyclic deformation response of HT-UPS is compared to that of 316 SS. The cycles to failure are similar, despite differences in peak stress profiles and the deformed microstructures. Cracking in both alloys is transgranular (initiation and propagation) in the case of continuous cycle fatigue, while the primary cracks also propagate transgranularly during creep-fatigue cycling. Internal grain boundary damage as a result of the tensile hold is present in the form of fine cracks for hold times of 3600 sec and longer and substantially more internal cracks are visible in 316 SS than HT-UPS. The dislocation substructures observed in the deformed material are different. An equiaxed cellular structure is observed in 316 SS, whereas tangles of dislocations are present at the nanoscale MC precipitates in HT-UPS and no cellular substructure is observed.

Mark Carroll; Laura Carroll

2011-09-01T23:59:59.000Z

380

2009 ASME WIND ENERGY SYMPOSIUM Static and Fatigue Testing of Thick Adhesive Joints for  

E-Print Network (OSTI)

1 2009 ASME WIND ENERGY SYMPOSIUM Static and Fatigue Testing of Thick Adhesive Joints for Wind as wind blade size has increased. Typical blade joints use paste adhesives several millimeters thick aircraft, which are also of relevance to wind blades in many instances. The strengths of lap-shear and many

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Analysis of SNL/MSU/DOE fatigue database trends for wind turbine blade materials.  

DOE Green Energy (OSTI)

This report presents an analysis of trends in fatigue results from the Montana State University program on the fatigue of composite materials for wind turbine blades for the period 2005-2009. Test data can be found in the SNL/MSU/DOE Fatigue of Composite Materials Database which is updated annually. This is the fifth report in this series, which summarizes progress of the overall program since its inception in 1989. The primary thrust of this program has been research and testing of a broad range of structural laminate materials of interest to blade structures. The report is focused on current types of infused and prepreg blade materials, either processed in-house or by industry partners. Trends in static and fatigue performance are analyzed for a range of materials, geometries and loading conditions. Materials include: sixteen resins of three general types, five epoxy based paste adhesives, fifteen reinforcing fabrics including three fiber types, three prepregs, many laminate lay-ups and process variations. Significant differences in static and fatigue performance and delamination resistance are quantified for particular materials and process conditions. When blades do fail, the likely cause is fatigue in the structural detail areas or at major flaws. The program is focused strongly on these issues in addition to standard laminates. Structural detail tests allow evaluation of various blade materials options in the context of more realistic representations of blade structure than do the standard test methods. Types of structural details addressed in this report include ply drops used in thickness tapering, and adhesive joints, each tested over a range of fatigue loading conditions. Ply drop studies were in two areas: (1) a combined experimental and finite element study of basic ply drop delamination parameters for glass and carbon prepreg laminates, and (2) the development of a complex structured resin-infused coupon including ply drops, for comparison studies of various resins, fabrics and pry drop thicknesses. Adhesive joint tests using typical blade adhesives included both generic testing of materials parameters using a notched-lap-shear test geometry developed in this study, and also a series of simulated blade web joint geometries fabricated by an industry partner.

Mandell, John F. (Montana State University, Bozeman, MT); Ashwill, Thomas D.; Wilson, Timothy J. (Montana State University, Bozeman, MT); Sears, Aaron T. (Montana State University, Bozeman, MT); Agastra, Pancasatya (Montana State University, Bozeman, MT); Laird, Daniel L.; Samborsky, Daniel D. (Montana State University, Bozeman, MT)

2010-12-01T23:59:59.000Z

382

Comparison of Low Cycle (Notch) Fatigue Behaviour at ...  

Science Conference Proceedings (OSTI)

as part of a life cycle costing approach during preliminary design ..... combined with the stress state at the notch root (which can be seen in Figure 9 to be ...

383

Development of reduced-variable master curves for estimating tensile stresses of encapsulated solar cells caused by module deflection or thermal expansion  

DOE Green Energy (OSTI)

Complex computer programs are being used by Spectrolab, Inc., to achieve encapsulation engineering optimization of photovoltaic modules. Optimization involves structural adequacy, electrical isolation (safety), maximum optical transmission, and minimum module temperature, at the lowest life-cycle energy cost. A goal of this activity is the generation, where possible, of encapsulation engineering generalities, principles, and design aids (tables or graphs) that would permit a ready, desktop capability of an engineering evaluation of encapsulation options involving materials or designs. The first efforts to generate reduced-variable mater curves for thermal expansion and deflection stress to serve as structural-analysis design aids are reported.

Cuddihy, E.F.

1981-10-01T23:59:59.000Z

384

Fatigue and Creep Crack Propagation behaviour of Alloy 617 in the Annealed and Aged Conditions  

Science Conference Proceedings (OSTI)

The crack propagation behaviour of Alloy 617 was studied under various conditions. Elevated temperature fatigue and creep-fatigue crack growth experiments were conducted at 650 and 800 degrees C under constant stress intensity (triangle K) conditions and triangular or trapezoidal waveforms at various frequencies on as-received, aged, and carburized material. Environmental conditions included both laboratory air and characteristic VHTR impure helium. As-received Alloy 617 displayed an increase in the crack growth rate (da/dN) as the frequency was decreased in air which indicated a time-dependent contribution component in fatigue crack propagation. Material aged at 650°C did not display any influence on the fatigue crack growth rates nor the increasing trend of crack growth rate with decreasing frequency even though significant microstructural evolution, including y’ (Ni3Al) after short times, occurred during aging. In contrast, carburized Alloy 617 showed an increase in crack growth rates at all frequencies tested compared to the material in the standard annealed condition. Crack growth studies under quasi-constant K (i.e. creep) conditions were also completed at 650 degrees C and a stress intensity of K = 40 MPa9 (square root)m. The results indicate that crack growth is primarily intergranular and increased creep crack growth rates exist in the impure helium environment when compared to the results in laboratory air. Furthermore, the propagation rates (da/dt) continually increased for the duration of the creep crack growth either due to material aging or evolution of a crack tip creep zone. Finally, fatigue crack propagation tests at 800 degrees C on annealed Alloy 617 indicated that crack propagation rates were higher in air than impure helium at the largest frequencies and lowest stress intensities. The rates in helium, however, eventually surpass the rates in air as the frequency is reduced and the stress intensity is decreased which was not observed at 650 degrees C.

Julian K. Benz; Richard N. Wright

2013-10-01T23:59:59.000Z

385

Javascript Design  

Science Conference Proceedings (OSTI)

From the Publisher:JavaScript Design shows designers how to create interactive JavaScript applications for the Web. It provides detailed descriptions of:JavaScript structures, statements and objectsUsing JavaScript to create different ...

Bill B. Sanders

2001-12-01T23:59:59.000Z

386

Estimating Carbon Supply Curves for Global Forests and Other Land Uses |  

Open Energy Info (EERE)

Estimating Carbon Supply Curves for Global Forests and Other Land Uses Estimating Carbon Supply Curves for Global Forests and Other Land Uses Jump to: navigation, search Tool Summary Name: Estimating Carbon Supply Curves for Global Forests and Other Land Uses Agency/Company /Organization: Resources for the Future Sector: Land Focus Area: Forestry, Agriculture Topics: GHG inventory, Resource assessment Resource Type: Guide/manual Website: www.rff.org/documents/RFF-DP-01-19.pdf Estimating Carbon Supply Curves for Global Forests and Other Land Uses Screenshot References: Estimating Carbon Supply Curves for Global Forests and Other Land Uses[1] Abstract "This study develops cumulative carbon "supply curves" for global forests utilizing an dynamic timber supply model for sequestration of forest carbon. Because the period of concern is the next century, and

387

The R-curve response of ceramics with microscopic reinforcements: Reinforcement and additive effects  

SciTech Connect

Using direct observations with the scanning electron and optical microscopes, simultaneous measurements of fracture resistance versus crack length (R-curve behavior) and crack interactions with microstructural features at the crack tip and in its wake were made. Selecting whisker-reinforced aluminas and self-reinforced silicon nitrides, one can examine the effects of systematic modifications of microstructure and composition on the R-curve response and the mechanisms giving rise to it. Specifically, increases in whisker content and size can increase the R-Curve response, even for short crack lengths. In the self-reinforced silicon nitrides, changes in alumina: yttria additive ratios also modify the R-curve. Modeling of the R-curve response allows one to verify toughening mechanisms and, with experimental studies, to optimize the R-curve behavior in ceramics containing microscopic reinforcements, e.g., whiskers and elongated grain structures.

Becher, P.F.; Sun, E.Y.; Plucknett, K,P.; Hsueh, C.H.

1996-05-01T23:59:59.000Z

388

Experimental design  

Science Conference Proceedings (OSTI)

Maximizing data information requires careful selection, termed design, of the points at which data are observed. Experimental design is reviewed here for broad classes of data collection and analysis problems, including: fractioning techniques ... Keywords: Key Design Issues in Data Mining, Science and Technology, Statistical Fundamentals

J. P. Morgan; Xinwei Deng

2012-03-01T23:59:59.000Z

389

R-curve response of silicon carbide whisker-reinforced alumina: Microstructural influence  

SciTech Connect

Rising fracture resistance with crack extension (R-curve response) can lead to improvements in the mechanical reliability of ceramics. To understand how microstructures influence the R-curve behavior, direct observations of crack interactions with microstructural features were conducted on SiC whisker-reinforced alumina. The contribution of the dominant toughening mechanisms to the R-curve behavior of these composites is discussed using experimental and theoretical studies.

Sun, E.Y.; Hsueh, C.H.; Becher, P.F.

1995-12-31T23:59:59.000Z

390

Conservation screening curves to compare efficiency investments to power plants: Applications to commercial sector conservation programs  

E-Print Network (OSTI)

and Ashok K. Gadgil. 1989. Conservation Screening Curves forof Utility Experience with Conservation and Load ManagementSupport Document: Energy Conservation Standards for Consumer

Koomey, Jonathan; Rosenfeld, Arthur H.; Gadgil, Ashok J.

2008-01-01T23:59:59.000Z

391

Stabilizing control of parallel AC-DC power transmission systems by approximate switching curve  

SciTech Connect

A method to improve the transient stability of bulk power transmission system is presented. The method stabilizes the control of parallel ac-dc transmission systems using an approximate switching curve. The optimal switching curve is approximated by a power series and the resulting switching curve is determined independent of type and duration of faults that occur to the system. In addition, coefficients of the switching curve can be calculated on a off-line basis which allows use of simple on-line algebraic calculations in emergency conditions.

Ichiyanagi, K.; Kobayashi, H.; Kakehu, H.

1980-01-01T23:59:59.000Z

392

Use of experience curves to estimate the future cost of power plants with CO2 capture  

E-Print Network (OSTI)

2004. Experience curves for power plant emission controlassessments of fossil fuel power plants with CO 2 capturethe future cost of power plants with CO 2 capture Edward S.

Rubin, Edward S.; Yeh, Sonia; Antes, Matt; Berkenpas, Michael; Davison, John

2007-01-01T23:59:59.000Z

393

A centurial history of technological change and learning curves or pulverized coal-fired utility boilers  

E-Print Network (OSTI)

OECD. Experience curves for energy technology policy. Paris,generation. National Energy Technology Laboratory, U.S. DOE;CO. Assessing new energy technologies using an energy system

Yeh, Sonia; Rubin, Edward

2007-01-01T23:59:59.000Z

394

Learning curves for environmental technology and their importance for climate policy analysis  

E-Print Network (OSTI)

DG. Dynamics of energy technologies and global change.CO. Experience curves for energy technology policy. Paris,o f technologies, including energy technologies [3-7]. Cost

Rubin, Edward S.; Taylor, Margaret R; Yeh, Sonia; Hounshell, David A.

2007-01-01T23:59:59.000Z

395

Use of experience curves to estimate the future cost of power plants with CO2 capture  

E-Print Network (OSTI)

the combined cycle gas turbine—an experience curve analysis.reduction (SCR) systems, gas turbine combined cycle (GTCC)catalytic reduction (SCR) Gas turbine combined cycle (GTCC)

Rubin, Edward S.; Yeh, Sonia; Antes, Matt; Berkenpas, Michael; Davison, John

2007-01-01T23:59:59.000Z

396

Economic growth and transition : econometric analysis of Lim's S-curve hypothesis.  

E-Print Network (OSTI)

??Professor Lim Chong Yah's S-Curve hypothesis is a simple yet highly insightful theory. By augmenting the mathematical and econometrical sophistication of the hypothesis, this thesis… (more)

Sng, Hui Ying.

2008-01-01T23:59:59.000Z

397

Decline curve analysis in unconventional resource plays using logistic growth models.  

E-Print Network (OSTI)

??Current models used to forecast production in unconventional oil and gas formations are often not producing valid results. When traditional decline curve analysis models are… (more)

Clark, Aaron James

2011-01-01T23:59:59.000Z

398

Designing Creativity  

E-Print Network (OSTI)

Is it possible to design for creativity? This is one of the most important research questions in AI and Design. This paper raises the question whether automated software agent design can be creative. Not only is the artefact dynamic in the sense that it adapts to its environment, it is also autonomous: an agent decides on its own when to be modified and by whom. An agent's functionality may evolve beyond the expectations of its designers and/or users resulting in very new, unique artefacts. Is this type of design creative? Is the process creative? The result? 1.

Frances M. T. Brazier; Niek J. E. Wijngaards

2002-01-01T23:59:59.000Z

399

Robust Entrainment of Circadian Oscillators Requires Specific Phase Response Curves  

E-Print Network (OSTI)

Function (BTDF); Architectural design; Daylighting simulation; Shadow volumes; Complex fenestration systems system (CFS) technologies to respond more efficiently to these parameters [6­9]. But only if daylighting with advanced fenestration products reveal additional chal- lenges for adoption: "This system produces not only

Lefranc, Marc

400

Robust entrainment of circadian oscillators requires specific phase response curves  

E-Print Network (OSTI)

, particularly in regard to daylighting and mechanical system operations, offer many lessons learned for ongoing, the designers of Wilson's daylighting systems used a combination of interior and exterior light shelves with the engineered daylighting system to augment it when needed. Using two rows of high-efficiency light fixtures

Lefranc, Marc

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Discrete sliding-mode control of a PWM inverter for sinusoidal output waveform synthesis with optimal sliding curve  

SciTech Connect

This paper presents a discrete sliding-mode control scheme with feedforward compensation for the closed-loop regulation of the pulse-width modulated (PWM) inverter used in an uninterruptible power supply (UPS). The proposed feedforward controller can effectively improve the tracking performance of the PWM inverter. In designing the sliding-mode controller, the authors have taken load disturbance into consideration to enhance the robustness of the PWM inverter. Moreover, the upper bound of the load disturbance under which the sliding condition can be maintained has also been derived. The sliding curve of the sliding-mode controller is designed such that the behavior of the controlled PWM inverter is optimal subject to the selected cost function. Due to the coordinate transformation proposed in this paper, only the output voltage needs to be measured as feedback for the purpose of closed-loop regulation. Simulation and experimental results are given to show the effectiveness of the proposed control scheme.

Jung, S.L.; Tzou, Y.Y. [National Chiao Tung Univ., Hsinchu (Taiwan, Province of China). Dept. of Control Engineering

1996-07-01T23:59:59.000Z

402

A Study on Fatigue-Crack-Deformation Behavior Following a Single ...  

Science Conference Proceedings (OSTI)

Apr 27, 2009 ... Width. Using this method, the respective crack—opening load (COL) at various crack-growth stages can be determined ?om the curve of the ...

403

TPX: Contractor preliminary design review. Volume 3, Design and analysis  

Science Conference Proceedings (OSTI)

Several models have been formed for investigating the maximum electromagnetic loading and magnetic field levels associated with the Tokamak Physics eXperiment (TPX) superconducting Poloidal Field (PF) coils. The analyses have been performed to support the design of the individual fourteen hoop coils forming the PF system. The coils have been sub-divided into three coil systems consisting of the central solenoid (CS), PF5 coils, and the larger radius PF6 and PF7 coils. Various electromagnetic analyses have been performed to determine the electromagnetic loadings that the coils will experience during normal operating conditions, plasma disruptions, and fault conditions. The loadings are presented as net body forces acting individual coils, spatial variations throughout the coil cross section, and force variations along the path of the conductor due to interactions with the TF coils. Three refined electromagnetic models of the PF coil system that include a turn-by-turn description of the fields and forces during a worst case event are presented in this report. A global model including both the TF and PF system was formed to obtain the force variations along the path of the PF conductors resulting from interactions with the TF currents. In addition to spatial variations, the loadings are further subdivided into time-varying and steady components so that structural fatigue issues can be addressed by designers and analysts. Other electromagnetic design issues such as the impact of the detailed coil designs on field errors are addressed in this report. Coil features that are analyzed include radial transitions via short jogs vs. spiral type windings and the effects of layer-to-layer rotations (i.e clocking) on the field errors.

NONE

1995-06-30T23:59:59.000Z

404

Application of the U.S. high cycle fatigue data base to wind turbine blade lifetime predictions  

DOE Green Energy (OSTI)

This paper demonstrates a methodology for predicting the service lifetime of wind turbine blades using the high-cycle fatigue data base for typical U.S. blade materials developed by Mandell, et al. (1995). The first step in the analysis is to normalize the data base (composed primarily of data obtained from specialized, relatively small coupons) with fatigue data from typical industrial laminates to obtain a Goodman Diagram that is suitable for analyzing wind turbine blades. The LIFE2 fatigue analysis code for wind turbines is then used for the fatigue analysis of a typical turbine blade with a known load spectrum. In the analysis, a linear damage model, Miner`s Rule, is used to demonstrate the prediction of the service lifetime for a typical wind turbine blade under assumed operating strain ranges and stress concentration factors. In contrast to typical European data, the asymmetry in this data base predicts failures under typical loads to be compressive.

Sutherland, H.J. [Sandia National Labs., Albuquerque, NM (United States); Mandell, J.F. [Montana State Univ., Bozeman, MT (United States)

1995-12-01T23:59:59.000Z

405

Coarsening of the Sn-Pb Solder Microstructure in Constitutive Model-Based Predictions of Solder Joint Thermal Mechanical Fatigue  

SciTech Connect

Thermal mechanical fatigue (TMF) is an important damage mechanism for solder joints exposed to cyclic temperature environments. Predicting the service reliability of solder joints exposed to such conditions requires two knowledge bases: first, the extent of fatigue damage incurred by the solder microstructure leading up to fatigue crack initiation, must be quantified in both time and space domains. Secondly, fatigue crack initiation and growth must be predicted since this metric determines, explicitly, the loss of solder joint functionality as it pertains to its mechanical fastening as well as electrical continuity roles. This paper will describe recent progress in a research effort to establish a microstructurally-based, constitutive model that predicts TMF deformation to 63Sn-37Pb solder in electronic solder joints up to the crack initiation step. The model is implemented using a finite element setting; therefore, the effects of both global and local thermal expansion mismatch conditions in the joint that would arise from temperature cycling.

Vianco, P.T.; Burchett, S.N.; Neilsen, M.K.; Rejent, J.A.; Frear, D.R.

1999-04-12T23:59:59.000Z

406

Thermo-mechanical fatigue of polycrystalline, directionally solidified and single crystal nickel base superalloys repaired by laser beam welding.  

E-Print Network (OSTI)

??The low cycle thermo-mechanical fatigue of laser beam welded conventionally cast Inconel 738, directionally solidified René 80 and single crystal René N5 has been evaluated.… (more)

Durocher, Jonathan

2013-01-01T23:59:59.000Z

407

Proceedings of the 2000 International Conference on Fatigue of Reactor Components (MRP-46): PWR Materials Reliability Program (PWRMR P)  

Science Conference Proceedings (OSTI)

This report contains information presented at the First International Conference on Fatigue of Reactor Components held July 31 - August 2, 2000, in Napa, California. The conference -- sponsored by EPRI, the Organisation for Economic Co-operation and Development Nuclear Energy Agency/Committee on the Safety of Nuclear Installations (OECD NEA/CSNI), and the U.S. Nuclear Regulatory Commission (U.S. NRC) -- provided a forum for the technical discussion of fatigue issues that affect the integrity and operatio...

2001-06-25T23:59:59.000Z

408

Materials characterization of silicon carbide reinforced titanium (Ti/SCS-6) metal matrix composites. Part 1: Tensile and fatigue behavior  

Science Conference Proceedings (OSTI)

Flexural fatigue behavior was investigated on titanium (Ti-15V-3Cr) metal matrix composites reinforced with cross-ply, continuous silicon carbide (SiC) fibers. The titanium composites had an eight-ply (0, 90, +45, {minus}45 deg) symmetric layup. Fatigue life was found to be sensitive to fiber layup sequence. Increasing the test temperature from 24 C to 427 C decreased fatigue life. Interface debonding and matrix and fiber fracture were characteristic of tensile behavior regardless of test temperature. In the tensile fracture process, interface debonding between SiC and the graphite coating and between the graphite coating and the carbon core could occur. A greater amount of coating degradation at 427 C than at 24 C reduced the Ti/SiC interface bonding integrity, which resulted in lower tensile properties at 427 C. During tensile testing, a crack could initiate from the debonded Ti/SiC interface and extend to the debonded interface of the neighboring fiber. The crack tended to propagate through the matrix and the interface. Dimpled fracture was the prime mode of matrix fracture. Interface debonding, matrix cracking, and fiber bridging were identified as the prime modes of fatigue mechanisms. To a lesser extent, fiber fracture was observed during fatigue. However, fiber fracture was believed to occur near the final stage of fatigue failure. In fatigued specimens, facet-type fracture appearance was characteristic of matrix fracture morphology. Theoretical modeling of the fatigue behavior of Ti/SCS-6 composites is presented in Part 2 of this series of articles.

Liaw, P.K. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Diaz, E.S. [Westinghouse Science and Technology Center, Pittsburgh, PA (United States); Chiang, K.T.; Loh, D.H. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.

1995-12-01T23:59:59.000Z

409

Comparison of Emperical Decline Curve Analysis for Shale Wells  

E-Print Network (OSTI)

This study compares four recently developed decline curve methods and the traditional Arps or Fetkovich approach. The four methods which are empirically formulated for shale and tight gas wells are: 1. Power Law Exponential Decline (PLE). 2. Stretched Exponential Decline (SEPD). 3. Duong Method. 4. Logistic Growth Model (LGM). Each method has different tuning parameters and equation forms. The main objective of this work is to determine the best method(s) in terms of Estimated Ultimate Recovery (EUR) accuracy, goodness of fit, and ease of matching. In addition, these methods are compared against each other at different production times in order to understand the effect of production time on forecasts. As a part of validation process, all methods are benchmarked against simulation. This study compares the decline methods to four simulation cases which represent the common shale declines observed in the field. Shale wells, which are completed with horizontal wells and multiple traverse highly-conductive hydraulic fractures, exhibit long transient linear flow. Based on certain models, linear flow is preceded by bilinear flow if natural fractures are present. In addition to this, linear flow is succeeded by Boundary Dominated Flow (BDF) decline when pressure wave reaches boundary. This means four declines are possible, hence four simulation cases are required for comparison. To facilitate automatic data fitting, a non-linear regression program was developed using excel VBA. The program optimizes the Least-Square (LS) objective function to find the best fit. The used optimization algorithm is the Levenberg-Marquardt Algorithm (LMA) and it is used because of its robustness and ease of use. This work shows that all methods forecast different EURs and some fit certain simulation cases better than others. In addition, no method can forecast EUR accurately without reaching BDF. Using this work, engineers can choose the best method to forecast EUR after identifying the simulation case that is most analogous to their field wells. The VBA program and the matching procedure presented here can help engineers automate these methods into their forecasting sheets.

Kanfar, Mohammed Sami

2013-08-01T23:59:59.000Z

410

Role of crack tip shielding in the initiation and growth of long and small fatigue cracks in composite microstructures  

Science Conference Proceedings (OSTI)

The role of crack tip shielding in retarding the initiation and growth of fatigue cracks has been examined in metallic composite microstructures (consisting of hard and soft phases), with the objective of achieving maximum resistance to fatigue. Specifically, duplex ferritic-martensitic structures have been developed in AISI 1008 and 1015 mild steels to promote shielding without loss in strength. The shielding is developed primarily from crack deflection and resultant crack closure, such that unusually high long crack propagation resistance is obtained. It is found that the fatigue threshold ..delta..K/sub TH/ in AISI 1008 can be increased by more than 100 pct to over 20 MPa ..sqrt..m, without sacrifice in strength, representing the highest ambient temperature threshold reported for a metallic alloy to date. Similar but smaller increases are found in AISI 1015. The effect of the dual-phase microstructures on crack initiation and small crack (10 to 1000 ..mu..m) growth, however, is markedly different, characteristic of behavior influenced by the mutual competition of intrinsic and extrinsic (shielding) ''toughening'' mechanisms. Accordingly, the composite microstructures which appear to show the highest resistance to the growth of long cracks, show the lowest resistance to crack initiation and small crack growth. In general, dual-phase steels are found to display remarkable fatigue properties, with fatigue limits as high as 58 pct of the tensile strengths and fatigue thresholds in the range of 13 to 20 MPa..sqrt..m.

Shang, J.K.; Tzou, J.L.; Ritchie, R.O. (Materials and Chemical Sciences Div., Lawrence Berkeley Lab., and Dept. of Materials Science and Mineral Engineering, Univ. of California, Berkeley, CA (US))

1987-09-01T23:59:59.000Z

411

The geometry of the critically-periodic curves in the space of cubic polynomials  

E-Print Network (OSTI)

We provide an algorithm for computing the Euler characteristic of the curves $S_p$ in the space of cubic polynomials, consisting of all polynomials with a periodic critical point of period $p$. The curves were introduced in [Milnor, Bonifant-Kiwi-Milnor], and the algorithm applies the main results of [DeMarco-Pilgrim]. The output is shown for periods $p \\leq 26$.

DeMarco, Laura

2012-01-01T23:59:59.000Z

412

High-speed hardware implementations of Elliptic Curve Cryptography: A survey  

Science Conference Proceedings (OSTI)

For the last decade, Elliptic Curve Cryptography (ECC) has gained increasing acceptance in the industry and the academic community and has been the subject of several standards. This interest is mainly due to the high level of security with relatively ... Keywords: Efficiency-flexibility tradeoffs, Elliptic Curve Cryptography, High-speed hardware implementation, Network applications, Public-key cryptography

Guerric Meurice de Dormale; Jean-Jacques Quisquater

2007-02-01T23:59:59.000Z

413

Serial Data Fusion Using Space-filling Curves in Wireless Sensor Networks  

E-Print Network (OSTI)

Serial Data Fusion Using Space-filling Curves in Wireless Sensor Networks Swapnil Patil and Samir R-- This paper considers serial fusion as a mechanism for collaborative signal detection. The advantage fusion based on simple models . We also develop a space-filling curve-based routing mechanism for message

Nasipuri, Asis

414

Effects of wind shear and turbulence on wind turbine power curves  

DOE Green Energy (OSTI)

It is a common practice to use wind speeds at hub height in determining wind turbine power curves. Although the possible influence of other variables (sub as turbulence and wind shear) is generally neglected in power curve measurements, we discovered the importance of other variables in an analysis of power curves for three 2.5 MW wind turbines. When the power curves were stratified by turbulence intensity. Such a large sensitivity to turbulence was not expected, and further analyses were conducted to determine if other factors accompanying the change in turbulence level could cause or contribute to the observed sensitivity of the power curves to turbulence. In summary, the sensitivity of the observed power curves was largely due to two factors: (1) an actual sensitivity to turbulence in determining the power curve and (2) the deviation of the disk-averaged velocity from the hub-height velocity under low turbulence conditions that were most prevalent at the site. An examination of the wind shear profiles over the height of the rotor disk revealed that low turbulence conditions were characterized by strong shear in the lower half of the rotor disk and weak or negative shear in the upper half. Implications of this analysis are that significant errors in power curve measurements can result if the effects of wind shear and turbulence are ignored. 7 refs., 6 figs.

Elliott, D.L. (Pacific Northwest Lab., Richland, WA (USA)); Cadogan, J.B. (USDOE, Washington, DC (USA))

1990-09-01T23:59:59.000Z

415

High-power I-V curve tracer employing a capacitive load  

SciTech Connect

A portable, photovoltaic voltage versus current curve tracer is discussed. The curve tracer employs a capacitive load to provide automatic sweeping of the array voltage. The unit is capable of measuring arrays up to 10 kW, but is similar and lighter than a conventional 2.5-kW dissipative load.

Warner, T.H.; Cox, C.H. III

1981-01-01T23:59:59.000Z

416

Explaining the light curves of Gamma-ray Bursts with precessing jets  

E-Print Network (OSTI)

A phenomenological model is presented to explain the light curves of gamma-ray bursts. Gamma-rays are produced in a narrow beam which sweeps through space due to the precession of a slaved accretion disc. The light curve expected from such a precessing luminosity cone can explain the complex temporal behavior of bright gamma-ray bursts.

Simon Portegies Zwart

1999-03-13T23:59:59.000Z

417

A C²-continous B-spline Quaternion Curve Interpolating a Given Sequence of Solid Orientations  

E-Print Network (OSTI)

An algorithm is presented that constructs a C²-continuous B-spline quaternion curve which interpolates a given sequence of unit quaternions on the rotation group SO(3). The de Casteljau type construction method of B-spline curves can be extended to generate B-spline quaternion curves [Sch92]; however, the B-spline quaternion curves do not have C²-continuity in SO(3). The authors [KKS94a] recently suggested a new construction method that can extend a Bspline curve to a similar one in SO(3) while preserving the C^k-continuity of the B-spline curve. We adapt this method for the construction of a B-spline quaternion interpolation curve. Thus, the problem essentially reduces to the problem of finding the control points for the B-spline interpolation curve. However, due to the non-linearity of the associated constraint equations, it is non-trivial to compute the B-spline control points. We provide an efficient iterative refinement solution which can approximate the control points...

Myoung-Jun Kim; Myung-soo Kim; Sung Yong Shin

1995-01-01T23:59:59.000Z

418

A Probabilistic Graphical Approach to Computing Electricity Price Duration Curves under Price and  

E-Print Network (OSTI)

A Probabilistic Graphical Approach to Computing Electricity Price Duration Curves under Price,oren}@ieor.berkeley.edu Abstract-- The electricity price duration curve (EPDC) repre- sents the probability distribution function of the electricity price considered as a random variable. The price uncertainty comes both from the demand side

Oren, Shmuel S.

419

MODULI SPACES OF PARABOLIC HIGGS BUNDLES AND PARABOLIC K(D) PAIRS OVER SMOOTH CURVES: I  

E-Print Network (OSTI)

MODULI SPACES OF PARABOLIC HIGGS BUNDLES AND PARABOLIC K(D) PAIRS OVER SMOOTH CURVES: I HANS U. BODEN AND K â?? OJI YOKOGAWA Abstract. This paper concerns the moduli spaces of rank two parabolic Higgs bundles and parabolic K(D) pairs over a smooth curve. Precisely which parabolic bundles occur in stable K

Boden, Hans U.

420

Hardware architectures for MSP430-based wireless sensor nodes performing elliptic curve cryptography  

Science Conference Proceedings (OSTI)

Maximizing the battery lifetime of wireless sensor nodes and equipping them with elliptic curve cryptography is a challenge that requires new energy-saving architectures. In this paper, we present an architecture that drops a hardware accelerator between ... Keywords: ASIC, MSP430, elliptic curve cryptography, hardware, software, wireless sensor nodes

Erich Wenger

2013-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Sampling points on regular parametric curves with control of their distribution  

Science Conference Proceedings (OSTI)

We propose an iterative algorithm to generate a sequence of a prescribed number of points on a parametric curve with control of their distribution. Our algorithm depends on a free parameter which controls the achievement of a final distribution of points ... Keywords: arc length parametrization, parametric curves, rational linear reparametrization, sampling points

Victoria Hernández-Mederos; Jorge Estrada-Sarlabous

2003-09-01T23:59:59.000Z

422

Melting curve and Hugoniot of molybdenum up to 400 GPa by ab initio simulations  

E-Print Network (OSTI)

with the high pressure melting curve from static compression experiments. Our calculated P(V ) and T(P) Hugoniot on new ab initio calculations of Tm(P) for Mo, and on the P(V ) and T(P) relations on the Hugoniot. We it to calculate melting curves. In such calculations, no empirical model is used to describe the interactions

Alfè, Dario

423

A parameterization of the Fermat curves satisfying x^(2N)+y^(2N)=1  

E-Print Network (OSTI)

Note that the family of closed curves C_N={(x,y)\\in R^2;x^(2N)+y^(2N)=1} for N=1,2,3,... approaches the boundary of [-1,1]^2 as N \\to \\infty. In this paper we exhibit a natural parameterization of these curves and generalize to a larger class of equations.

Kerry M. Soileau

2007-07-20T23:59:59.000Z

424

Progress Letter Report on Bending Fatigue Test System Development for Spent Nuclear Fuel Vibration Integrity Study (Out-of-cell fatigue testing development - Task 2.4)  

SciTech Connect

Vibration integrity of high burn-up spent nuclear fuel in transportation remains to be a critical component of US nuclear waste management system. The structural evaluation of package for spent fuel transportation eventually will need to see if the content or spent fuel is in a subcritical condition. However, a system for testing and characterizing such spent fuel is still lacking mainly due to the complication involved with dealing radioactive specimens in a hot cell environment. Apparently, the current state-of-the-art in spent fuel research and development is quite far away from the delivery of reliable mechanical property data for the assessment of spent fuels in the transport package evaluation. Under the sponsorship of US NRC, ORNL has taken the challenge in developing a robust testing system for spent fuel in hot cell. An extensive literature survey was carried out and unique requirements of such testing system were identified. The U-frame setup has come to the top among various designs examined for reverse bending fatigue test of spent fuel rod. The U-frame has many features that deserve mentioned here: Easy to install spent fuel rod in test; Less linkages than in conventional bending test setup such as three-point or four-point bending; Target the failure mode relevant to the fracture of spent fuel rod in transportation by focusing on pure bending; The continuous calibrations and modifications resulted in the third generation (3G) U-frame testing setup. Rigid arms are split along the LBB axis at rod sample ends. For each arm, this results in a large arm body and an end piece. Mating halves of bushings were modified into two V-shaped surfaces on which linear roller bearings (LRB) are embedded. The rod specimen is installed into the test fixture through opening and closing slide end-pieces. The 3G apparently has addressed major issues of setup identified in the previous stage and been proven to be eligible to be further pursued in this project. On the other hand, the purchase of universal testing machine or Bose dual LM2 TB was completed and the testing system was delivered to ORNL in August 2012. The preliminary confirmation of the system and on-site training were given by Bose field engineer and regional manager on 8/1-8/2/2012. The calibration of Bose testing system has been performed by ORNL because the integration of ORNL setup into the Bose TestBench occurred after the installation. Major challenge with this process arose from two aspects: 1) the load control involves two load cells, and 2) U-frame setup itself is a non-standard specimen. ORNL has been able to implement the load control through Cycle Indirect along with pinning the U-frame setup. Two meetings with ORNL hot-cell group (November 2012 and January 2013) were held to discuss the potential issues with both epoxy mounting of rigid sleeve and U-frame setup. Many suggestions were provided to make the procedure friendlier to the manipulator in hot cell. Addressing of these suggestions resulted in another cycle of modifications of both vise mold and setup. The initial meeting with ORNL I&C group occurred in November 2012 with regard to the Bose cable modification and design of central panel to integrate the cables and wires. The first round of cable modification and central panel fabrication was completed in February 2012. The testing with the modified cables exhibited substantial noises and the testing system was not shown to be stable. It was believed the cross talk was responsible to the noise, and a central panel with a better grounding and shielding was highly recommended. The central panel has been re-designed and fabricated in March 2013. In the subsequent period, the ORNL made substantial effort to debug the noises with the load cell channel, and to resolve the noises and nonlinearity with RDP LVDTs related to the integration of RDP LVDTs to Bose system. At the same time, ORNL has completed the verification tests of Bose test system, including cycle tests under reversal bending in load control, bending tests under monotonic load, and cycle test

Wang, Jy-An John [ORNL; Wang, Hong [ORNL; Cox, Thomas S [ORNL; Baldwin, Charles A [ORNL; Bevard, Bruce Balkcom [ORNL

2013-08-01T23:59:59.000Z

425

Surface Studies of Ultra Strength Drilling Steel after Corrosion Fatigue in Simulated Sour Environment  

Science Conference Proceedings (OSTI)

The Unites States predicted 60% growth in energy demand by 2030 makes oil and natural gas primary target fuels for energy generation. The fact that the peak of oil production from shallow wells (industry into deeper wells. However, drilling to depths greater than 5000 m requires increasing the strength-to weight ratio of the drill pipe materials. Grade UD-165 is one of the ultra- high yield strength carbon steels developed for ultra deep drilling (UDD) activities. Drilling UDD wells exposes the drill pipes to Cl{sup -}, HCO{sub 3}{sup -}/CO{sub 3}{sup 2-}, and H{sub 2}S-containig corrosive environments (i.e., sour environments) at higher pressures and temperatures compared to those found in conventional wells. Because of the lack of synergism within the service environment, operational stresses can result in catastrophic brittle failures characteristic for environmentally assisted cracking (EAC). Approximately 75% of all drill string failures are caused by fatigue or corrosion fatigue. Since there is no literature data on the corrosion fatigue performance of UD-165 in sour environments, research was initiated to better clarify the fatigue crack growth (FCGR) behavior of this alloy in UDD environments. The FCGR behavior of ultra-strength carbon steel, grade UD-165, was investigated by monitoring crack growth rate in deaerated 5%NaCl solution buffered with NaHCO{sub 3}/Na{sub 2}CO{sub 3} and in contact with H{sub 2}S. The partial pressure of H{sub 2}S (p{sub H2S}) was 0.83 kPa and pH of the solution was adjusted by NaOH to 12. The fatigue experiments were performed at 20 and 85 C in an autoclave with surface investigations augmented by scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) spectroscopy. In this study, research focused on surface analyses supported by the fatigue crack growth rate measurements. Fig. 1 shows an SEM micrograph of the crack that propagated from the notch in the solution at 20 C. Accumulation of the corrosion products is visible along the crack. The EDX chemical analysis near the crack tip found iron, sulfur and oxygen in the passive layer. The surface of the sample after the fatigue test in the sour environment at 85{sup o}, Fig. 2, C looks different from that fatigued surface at 20 C. The crack propagates across the passive film that covers the surface fairly uniformly. Some spallation of the passive film is observed near the notch. The EDX chemical analysis of the passive film near the crack tip identified mainly iron, carbon and oxygen. It appears that temperature plays a very important role in formation of the passive film. This may be associated with different solubility of H{sub 2}S in the solution, which will be further studied.

M. Ziomek-Moroz; J.A. Hawk; R. Thodla; F. Gui

2012-05-06T23:59:59.000Z

426

Surface Studies of Ultra Strength Drilling Steel after Corrosion Fatigue in Simulated Sour Environment  

SciTech Connect

The Unites States predicted 60% growth in energy demand by 2030 makes oil and natural gas primary target fuels for energy generation. The fact that the peak of oil production from shallow wells (< 5000 m) is about to be reached, thereby pushing the oil and natural gas industry into deeper wells. However, drilling to depths greater than 5000 m requires increasing the strength-to weight ratio of the drill pipe materials. Grade UD-165 is one of the ultra- high yield strength carbon steels developed for ultra deep drilling (UDD) activities. Drilling UDD wells exposes the drill pipes to Cl{sup -}, HCO{sub 3}{sup -}/CO{sub 3}{sup 2-}, and H{sub 2}S-containig corrosive environments (i.e., sour environments) at higher pressures and temperatures compared to those found in conventional wells. Because of the lack of synergism within the service environment, operational stresses can result in catastrophic brittle failures characteristic for environmentally assisted cracking (EAC). Approximately 75% of all drill string failures are caused by fatigue or corrosion fatigue. Since there is no literature data on the corrosion fatigue performance of UD-165 in sour environments, research was initiated to better clarify the fatigue crack growth (FCGR) behavior of this alloy in UDD environments. The FCGR behavior of ultra-strength carbon steel, grade UD-165, was investigated by monitoring crack growth rate in deaerated 5%NaCl solution buffered with NaHCO{sub 3}/Na{sub 2}CO{sub 3} and in contact with H{sub 2}S. The partial pressure of H{sub 2}S (p{sub H2S}) was 0.83 kPa and pH of the solution was adjusted by NaOH to 12. The fatigue experiments were performed at 20 and 85 C in an autoclave with surface investigations augmented by scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) spectroscopy. In this study, research focused on surface analyses supported by the fatigue crack growth rate measurements. Fig. 1 shows an SEM micrograph of the crack that propagated from the notch in the solution at 20 C. Accumulation of the corrosion products is visible along the crack. The EDX chemical analysis near the crack tip found iron, sulfur and oxygen in the passive layer. The surface of the sample after the fatigue test in the sour environment at 85{sup o}, Fig. 2, C looks different from that fatigued surface at 20 C. The crack propagates across the passive film that covers the surface fairly uniformly. Some spallation of the passive film is observed near the notch. The EDX chemical analysis of the passive film near the crack tip identified mainly iron, carbon and oxygen. It appears that temperature plays a very important role in formation of the passive film. This may be associated with different solubility of H{sub 2}S in the solution, which will be further studied.

M. Ziomek-Moroz; J.A. Hawk; R. Thodla; F. Gui

2012-05-06T23:59:59.000Z

427

Approach to the fatigue analysis of vertical-axis wind-turbine blades  

DOE Green Energy (OSTI)

A cursory analysis of the stress history of wind turbine blades indicates that a single stress level at each wind speed does not adequately describe the blade stress history. A statistical description is required. Blade stress data collected from the DOE/ALCOA Low Cost experimental turbines indicate that the Rayleigh probability density function adequately describes the distribution of vibratory stresses at each wind speed. The Rayleigh probability density function allows the distribution of vibratory stresses to be described by the RMS of the stress vs. time signal. With the RMS stress level described for all wind speeds, the complete stress history of the turbine blades is known. Miner's linear cumulative damage rule is used as a basis for summing the fatigue damage over all operating conditions. An analytical expression is derived to predict blade fatigue life.

Veers, P.S.

1981-09-01T23:59:59.000Z

428

Low Carbon Growth: a Potential Path for Mexico - GHG Abatement Cost Curve |  

Open Energy Info (EERE)

Growth: a Potential Path for Mexico - GHG Abatement Cost Curve Growth: a Potential Path for Mexico - GHG Abatement Cost Curve (Redirected from Mexico-McKinsey GHG Abatement Cost Curve) Jump to: navigation, search Name Low Carbon Growth: a Potential Path for Mexico - GHG Abatement Cost Curve Agency/Company /Organization Centro Mario Molina, McKinsey and Company Sector Energy, Land Focus Area Energy Efficiency, Renewable Energy Topics Resource assessment, Background analysis Website http://www.esmap.org/filez/pub Country Mexico Central America References ESMAP Low Carbon Growth Country Studies Program[1] References ↑ "ESMAP Low Carbon Growth Country Studies Program" Retrieved from "http://en.openei.org/w/index.php?title=Low_Carbon_Growth:_a_Potential_Path_for_Mexico_-_GHG_Abatement_Cost_Curve&oldid=3289

429

Supply Curves for Solar PV-Generated Electricity for the United States  

DOE Green Energy (OSTI)

Energy supply curves attempt to estimate the relationship between the cost of an energy resource and the amount of energy available at or below that cost. In general, an energy supply curve is a series of step functions with each step representing a particular group or category of energy resource. The length of the step indicates how much of that resource is deployable or accessible at a given cost. Energy supply curves have been generated for a number of renewable energy sources including biomass fuels and geothermal, as well as conservation technologies. Generating a supply curve for solar photovoltaics (PV) has particular challenges due to the nature of the resource. The United States has a massive solar resource base -- many orders of magnitude greater than the total consumption of energy. In this report, we examine several possible methods for generating PV supply curves based exclusively on rooftop deployment.

Denholm, P.; Margolis, R.

2008-11-01T23:59:59.000Z

430

Materials Reliability Program: Third International Conference on Fatigue of Reactor Components (MRP-151)  

Science Conference Proceedings (OSTI)

These proceedings contain information presented at the Third International Conference on Fatigue of Reactor Components held October 3-6, 2004, in Seville, Spain. This third conference was again sponsored by EPRI, the Organisation for Economic Co-Operation and Development (OECD) Nuclear Energy Agency/Committee on the Safety of Nuclear Installations (NEA/CSNI), and the U. S. Nuclear Regulatory Commission (NRC) and hosted by Consejo de Segurida Nuclear (CNS) of Spain.

2005-09-12T23:59:59.000Z

431

Procurement Specification for Horizontal Gas Path Heat Recovery Steam Generator: Avoiding Thermal-Mechanical Fatigue Damage  

Science Conference Proceedings (OSTI)

Many heat recovery steam generators (HRSGs), particularly those equipped with F-class gas turbines that are also subjected to periods of frequent cyclic operation, have experienced premature pressure part failures because of excessive thermal-mechanical fatigue (TMF) damage. The very competitive power generation marketplace has resulted in lowest installed cost often taking precedence over medium- and long-term durability and operating costs.

2009-12-23T23:59:59.000Z

432

Steam Generator Management Program: Onset of Fatigue Cracking in Steam Generator Tubes With Through Wall Flaws  

Science Conference Proceedings (OSTI)

Leak rate tests of steam generator tubing with stress corrosion cracks and electrodischarge machining notches were conducted at Argonne National Laboratory (ANL) under the sponsorship of the U.S. Nuclear Regulatory Commission. Some test specimens displayed a significant leak rate increase under constant pressure hold. It was suspected that fatigue caused by jet–structure interaction was responsible for the increased leak rate. EPRI Reports 1015123 and 1016560 investigated the ANL test results in terms of...

2011-11-10T23:59:59.000Z

433

Environmentally Assisted Fatigue (EAF) Screening: Process and Technical Basis for Identifying EAF Limiting Locations  

Science Conference Proceedings (OSTI)

This report provides the technical basis and process for a screening evaluation of a nuclear power plant. This screening will identify appropriate limiting locations for systematic monitoring of the environmentally assisted fatigue (EAF) effects in a Class 1 reactor on the reactor coolant pressure boundary components that are wetted with primary coolant. Use of this process will ensure that the most limiting locations for EAF are determined on a consistent basis.The process developed in ...

2012-09-06T23:59:59.000Z

434

Design Specifications  

NLE Websites -- All DOE Office Websites (Extended Search)

Design Design Specifications Services Overview ECS Audio/Video Conferencing Fasterdata IPv6 Network Network Performance Tools (perfSONAR) ESnet OID Registry PGP Key Service Virtual Circuits (OSCARS) OSCARS Case Study Documentation User Manual FAQ Design Specifications Functional Specifications Notifications Publications Authorization Policy Default Attributes Message Security Clients For Developers Interfaces Links Hardware Requirements DOE Grids Service Transition Contact Us Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site Feedback: info@es.net Design Specifications OSCARS Reservation Manager - Design Specifications Year 3 Update (DRAFT) David Robertson, Chin Guok

435

Effect of Load Phase Angle on Wind Turbine Blade Fatigue Damage: Preprint  

DOE Green Energy (OSTI)

This paper examines the importance of phase angle variations with respect to fatigue damage. The operating loads on a generic conventional three-bladed upwind 1.5-MW wind turbine blade were analyzed over a range of operating conditions, and an aggregate probability distribution for the actual phase angles between the in-plane (lead-lag) and out-of-plane (flap) loads was determined. Using a finite element model of a generic blade and Miner's Rule, the accumulated theoretical damage (based on axial strains) resulting from a fatigue test with variable phase angles was compared to the damage resulting from a fatigue test with a constant phase angle. The nodal damage distribution at specific blade cross-sections are compared for the constant and variable phase angle cases. The sequence effects of various phase angle progressions were also considered. For this analysis, the finite element results were processed using the nonlinear Marco-Starkey damage accumulation model. Each phase angle sequence was constrained to have the same overall phase angle distribution and the same total number of cycles but the order in which the phase angles were applied was varied.

White, D. L.; Musial, W. D.

2003-11-01T23:59:59.000Z

436

A generalized fitting technique for the LIFE2 fatigue analysis code  

DOE Green Energy (OSTI)

The analysis of component fatigue lifetime for a wind energy conversion system (WECS) requires that the component load spectrum be formulated in terms of stress cycles. Typically, these stress cycles are obtained from time series data using a cycle identification scheme. As discussed by many authors, the matrix or matrices of cycle counts that describe the stresses on a turbine are constructed from relatively short, representative samples of time series data. The ability to correctly represent the long-term behavior of the distribution of stress cycles from these representative samples is critical to the analysis of service lifetimes. Several techniques are currently used to convert representative samples to the lifetime cyclic loads on the turbine. There has been recently developed a set of fitting algorithms that is particularly useful for matching the body of the distribution of fatigue stress cycles on a turbine component. Fitting techniques are now incorporated into the LIFE2 fatigue/fracture analysis code for wind turbines. In this paper, the authors provide an overview of the fitting algorithms and describe the pre- and post-count algorithms developed to permit their use in the LIFE2 code. Typical case studies are used to illustrate the use of the technique.

Sutherland, H.J. [Sandia National Labs., Albuquerque, NM (United States). Wind Energy Research Dept.; Wilson, T. [Univ. of New Mexico, Albuquerque, NM (United States). New Mexico Engineering Research Inst.

1996-08-01T23:59:59.000Z

437

Fatigue failure of regenerator screens in a high frequency Stirling engine  

DOE Green Energy (OSTI)

Failure of Stirling Space Power Demonstrator Engine (SPDE) regenerator screens was investigated. After several hours of operation the SPDE was shut down for inspection and upon removal of the regenerator screens, debris of an unknown origin was discovered along with considerable cracking of the screens in localized areas. Metallurgical analysis of the debris determined it to be cracked-off-deformed pieces of the 41 pm thickness Type 304 stainless steel wire screen. Scanning electron microscopy of the cracked screens revealed failures occurring at wire crossovers and fatigue striations on the fracture surface of the wires. Thus, the screen failure can be characterized as a fatigue failure of the wires. The crossovers were determined to contain a 30 percent reduction in wire thickness and a highly worked microstructure occurring from the manufacturing process of the wire screens. Later it was found that reduction in wire thickness occurred because the screen fabricator had subjected the screen to a light cold-roll process after weaving. Installation of this screen left a clearance in the regenerator allowing the screens to move. The combined effects of the reduction in wire thickness, stress concentration (caused by screen movement), and highly worked microstructure at the wire crossovers led to the fatigue failure of the screens.

Hull, D.R.; Alger, D.L.; Moore, T.J.; Sheuermann, C.M.

1987-03-01T23:59:59.000Z

438

Hydrogen induced surface cracking in an 8090 Al-Li alloy during high cycle fatigue  

Science Conference Proceedings (OSTI)

In recent years, there has been an increasing interest in understanding the effects of aggressive or moist environments on the properties of Al-Li alloys. However, most of the existing work has been focused on their stress corrosion cracking resistance. Consequently, only a few reports are available on the environmental fatigue strength of these alloys. Upon exposure to aggressive environments, the fatigue crack propagation resistance can be detrimentally affected. R. Piascik and R. Gangloff found enhanced cyclic crack growth rates in an Al-Li-Cu alloy when a critical water vapor pressure was exceeded. Thermodynamically, at atmospheric pressures, strong interactions between hydrogen and lithium are expected to give rise to stable lithium hydrides. Evidence for the development of hydride phases in Al-Li alloys exposed to hydrogen environments has been reported by various workers. Thus, it is likely that HE via hydride formation can be the relevant mechanisms in Al-Li alloys that have been in contact with hydrogen. Since lithium hydrides are stable up to temperatures of 773 K, previous hydrogen exposure can lead to an irreversible mode of embrittlement. Thus, it was the objective of the present work to investigate the effects of hydrogen during aging on the ensuing high cycle fatigue (HCF) performance of an 8090 Al-Li alloy.

Laffin, C.; Raghunath, C.R.; Lopez, H.F. (Univ. of Wisconsin, Milwaukee, WI (United States). Materials Dept.)

1993-10-01T23:59:59.000Z

439

Steam Generator Management Program: Generic Elements of U-Bend Tube Vibration Induced Fatigue Analysis for Westinghouse Model F Steam Generators  

Science Conference Proceedings (OSTI)

U-bend tube ruptures due to metal fatigue have been experienced by several utilities worldwide. The first fatigue-related tube rupture occurred at North Anna Unit 1 in 1987. The knowledge gained from this event provides the basis for estimating the potential for a fatigue failure in other plants. This report provides the generic information for a Westinghouse Model F steam generator, and defines the information required to complete a plant-specific u-bend analysis to determine susceptibility to ...

2013-12-02T23:59:59.000Z

440

Flexural Fatigue Performance of CFRP Prestressed Concrete Poles  

E-Print Network (OSTI)

Applications, ACI Special Publication SP245-1, Eds R. El-Hacha and S.H. Rizkalla. [17] BS EN 1992-1-1:2004 (2004). Eurocode 2: Design of Concrete Structures. General Rules and Rules for Buildings, BSI. [18] Terrasi G.P. and Lees, J.M. (2006). CFRP... . However, as the deflection under a 6 point load is greater than the deflection under an equivalent UDL, this is a conservative approach. The span and loading arrangements were selected based on a sectional analysis of the critical cross...

Roberts, E. E.; Lees, J. M.; Hoult, N. A.

2012-04-24T23:59:59.000Z

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Conservation screening curves to compare efficiency investments topower plants: Applications to commercial sector conservationprograms  

SciTech Connect

This paper describes a simplified methodology to compare supply and demand-side resources. The screening curve approach supplements with load shape information the data contained in a supply curve of conserved energy. In addition, a screening curve contains information on competing supply technologies, such as annualized capital costs, variable costs, and cost per delivered kWh. The information in the screening curve allows policymakers to promptly and conveniently compare the relevant parameters affecting supply and demand-side investment decisions. While many sophisticated computer models have evolved to account for the load shape impacts of energy efficiency investments, this sophistication has, by and large, not trickled down to spreadsheet-level or 'back-of-the-envelope' analyses. Our methodology allows a simple summary of load shape characteristics based on the output of the more complicated models. It offers many advantages, principal of which is clarity in analyzing supply and demand-side investment choices. This paper first describes how supply-side screening curves have been used in the past, and develops the conceptual tools needed to apply integrated supply/demand screening curves in the least-cost utility planning process. It then presents examples of supply-side technologies and commercial sector demand-side management programs, and plots them on representative screening curves.

Koomey, Jonathan; Rosenfeld, Arthur H.; Gadgil, Ashok J.

1990-08-01T23:59:59.000Z

442

Determination of Cepheid parameters by light-curve template-fitting  

E-Print Network (OSTI)

We describe techniques to characterise the light-curves of regular variable stars by applying principal component analysis (PCA) to a training set of high quality data, and to fit the resulting light-curve templates to sparse and noisy photometry to obtain parameters such as periods, mean magnitudes etc. The PCA approach allows us to efficiently represent the multi-band light-curve shapes of each variable, and hence quantitatively describe the average behaviour of the sample as a smoothly varying function of period, and also the range of variation around this average. In this paper we focus particularly on the utility of such methods for analysing HST Cepheid photometry, and present simulations which illustrate the advantages of our PCA template-fitting approach. These are: accurate parameter determination, including light-curve shape information; simultaneous fitting to multiple passbands; quantitative error analysis; objective rejection of variables with non Cepheid-like light-curves or those with potential period aliases. We also use PCA to confirm that Cepheid light-curve shapes are systematically different (at the same period) between the Milky Way (MW) and the Large and Small Magellanic Clouds (LMC, SMC), and consider whether light-curve shape might therefore be used to estimate the mean metallicities of Cepheid samples, thus allowing metallicity corrections to be applied to derived distance estimates.

N. R. Tanvir; M. A. Hendry; A. Watkins; S. M. Kanbur; L. N. Berdnikov; C. C. Ngeow

2005-04-19T23:59:59.000Z

443

A dual-channel, curved-crystal spectrograph for petawatt laser, x-ray backlighter source studies  

Science Conference Proceedings (OSTI)

A dual-channel, curved-crystal spectrograph was designed to measure time-integrated x-ray spectra in the {approx}1.5 to 2 keV range (6.2-8.2 A wavelength) from small-mass, thin-foil targets irradiated by the VULCAN petawatt laser focused up to 4x10{sup 20} W/cm{sup 2}. The spectrograph consists of two cylindrically curved potassium-acid-phthalate crystals bent in the meridional plane to increase the spectral range by a factor of {approx}10 compared to a flat crystal. The device acquires single-shot x-ray spectra with good signal-to-background ratios in the hard x-ray background environment of petawatt laser-plasma interactions. The peak spectral energies of the aluminum He{sub {alpha}} and Ly{sub {alpha}} resonance lines were {approx}1.8 and {approx}1.0 mJ/eV sr ({approx}0.4 and 0.25 J/A sr), respectively, for 220 J, 10 ps laser irradiation.

Theobald, W.; Stoeckl, C.; Jaanimagi, P. A.; Nilson, P. M.; Storm, M.; Meyerhofer, D. D.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Hey, D.; MacKinnon, A. J.; Park, H.-S.; Patel, P. K.; Shepherd, R.; Snavely, R. A.; Key, M. H. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550-9234 (United States); King, J. A.; Zhang, B. [Department of Applied Sciences, University of California, Davis, Davis, California 95616 (United States); Stephens, R. B.; Akli, K. U. [General Atomics, San Diego, California 92186 (United States); Highbarger, K.; Daskalova, R. L. [College of Mathematical and Physical Sciences, Ohio State University, Columbus, Ohio 43210 (United States); and others

2009-08-15T23:59:59.000Z

444

Engitectural Design  

E-Print Network (OSTI)

Traditionally, Architecture and Engineering have been disciplines practiced exclusive of one another's input and collaboration. This seemingly awkward custom is due in part to tradition and to the two distinct perspectives each discipline has concerning the function of a building and it's many components. In the past, collaboration on a project generally occurred out of necessity, and can usually be attributed to a system and design integration problems. In most instances, these issues are related to the mechanical systems of building, and in a hot and humid climate the issues are magnified. Therefore, this paper will discuss the concepts and merits of a new design process called: Engitectural Design. Engitectural Design is the concept of blending the many design and aesthetic concerns of architecture with the more technical aspects of engineering, especially in the area of mechanical HVAC systems. The use of this new design procedure will reduce, if not eliminate, current problems with clearances, mechanical room size and optimal area selection. Merely incorporating the mechanical needs of a building during the schematic phase will reduce communication problems that cause the above mentioned problems, and thus optimize the system. This paper will address the mutual concerns of both professions as it pertains to materials, lighting, surface finishes, passive and active solar and the use of landscaping, focusing on the benefits of mutual agreement in a hot and humid climate. To be successful, the collaboration must begin in pre-design and continue through project completion. During initial implementation of Engitectural Design, a fm can expect each phase of a project to take longer than usual. Lack of established relationships, poor communication and professional territorial rights will exist in the beginning. However, over time a fm can expect a time reduction due to fewer revisions and the elimination of duplicated work. As it pertains to today's more advanced HVAC systems, this new cooperation and understanding of the needs within disciplines will yield a more effective and efficient operating unit for today's hot and humid environment.

Gagliardi, D. R.

1996-01-01T23:59:59.000Z

445

Energy Injection Episodes in Gamma Ray Bursts: The Light Curves and Polarization Properties of GRB 021004  

E-Print Network (OSTI)

Several GRB afterglow light curves deviate strongly from the power law decay observed in most bursts. We show that these variations can be accounted for by including refreshed shocks in the standard fireball model previously used to interpret the overall afterglow behavior. As an example we consider GRB 021004 that exhibited strong light curve variations and has a reasonably well time-resolved polarimetry. We show that the light curves in the R-band, X-rays and in the radio can be accounted for by four energy injection episodes in addition to the initial event. The polarization variations are shown to be a consequence of the injections.

Björnsson, G; Johannesson, G

2004-01-01T23:59:59.000Z

446

Energy Injection Episodes in Gamma Ray Bursts: The Light Curves and Polarization Properties of GRB 021004  

E-Print Network (OSTI)

Several GRB afterglow light curves deviate strongly from the power law decay observed in most bursts. We show that these variations can be accounted for by including refreshed shocks in the standard fireball model previously used to interpret the overall afterglow behavior. As an example we consider GRB 021004 that exhibited strong light curve variations and has a reasonably well time-resolved polarimetry. We show that the light curves in the R-band, X-rays and in the radio can be accounted for by four energy injection episodes in addition to the initial event. The polarization variations are shown to be a consequence of the injections.

G. Bjornsson; E. H. Gudmundsson; G. Johannesson

2004-09-24T23:59:59.000Z

447

Voltage-current curves for a planar symmetrical diode with reverse bias  

Science Conference Proceedings (OSTI)

We have examined thermionic emission for the (110) crystallographic plane (face) in W and have examined the voltage-current curves in the retarding-potential range. The diode had cathode and anode composed of identical (100) and (111) faces of tungsten single crystals having 99.999 wt. % purity. The back-bias curves measured with a tungsten single crystal are described for T > /Theta//sub te/ by an expression derived for a recombination-emission model. These curves and the temperature dependence of the intensity for the recombination-emission spectra have been used to determine the electron excitation energy.

Azizov, E.E.; Babaev, V.G.; Mashtakova, V.A.

1988-07-01T23:59:59.000Z

448

Development of In-Situ Fan Curve Measurement with One Airflow Measurement  

E-Print Network (OSTI)

Fan airflow is the key parameter for air volume tracking control in variable air volume systems. One of the airflow measurement methods is to determine airflow using the fan speed, fan head, and fan curve. Both fan speed and fan head can be measured accurately. Therefore, the accuracy of the fan airflow depends on the accuracy of the fan curve. An experimental method has been developed to determine the in-situ fan curve with only one airflow measurement. This paper presents the theoretical background, experimental procedures, and verification results.

Liu, G.; Joo, I. S.; Song, L.; Liu, M.

2003-01-01T23:59:59.000Z

449

DESIGN FOR AN AUTOGRAPHICALLY RECORDING TENSILE MACHINE  

SciTech Connect

An improved "hard" type tensile machine is described, designed primarily for metallurgical usage. Compactness and mechanical simplicity are combined with maximum accessibility of the load measuring device and specimen, and the load is measured with an electro-mechanical dynamometer which is easily adapted into a system for autographically recording ihe load-elongaticn curve. The machine should be particularly useful for dry-box or hot-cell work. (auth)

Adams, M.A.

1959-10-01T23:59:59.000Z

450

Nondestructive method and apparatus for imaging grains in curved surfaces of polycrystalline articles  

DOE Patents (OSTI)

A nondestructive method, and associated apparatus, are provided for determining the grain flow of the grains in a convex curved, textured polycrystalline surface. The convex, curved surface of a polycrystalline article is aligned in a horizontal x-ray diffractometer and a monochromatic, converging x-ray beam is directed onto the curved surface of the polycrystalline article so that the converging x-ray beam is diffracted by crystallographic planes of the grains in the polycrystalline article. The diffracted x-ray beam is caused to pass through a set of horizontal, parallel slits to limit the height of the beam and thereafter. The linear intensity of the diffracted x-ray is measured, suing a linear position sensitive proportional counter, as a function of position in a direction orthogonal to the counter so as to generate two dimensional data. An image of the grains in the curved surface of the polycrystalline article is provided based on the two-dimensional data.

Carpenter, D.A.

1993-09-08T23:59:59.000Z

451

Dependence of Sea Ice Yield-Curve Shape on Ice Thickness  

Science Conference Proceedings (OSTI)

In this note, the authors discuss the contribution that frictional sliding of ice floes (or floe aggregates) past each other and pressure ridging make to the plastic yield curve of sea ice. Using results from a previous study that explicitly ...

Alexander V. Wilchinsky; Daniel L. Feltham

2004-12-01T23:59:59.000Z

452

Spectral properties and reflectance curves of the revealed volcanic rocks in Syria using radiometric measurements  

Science Conference Proceedings (OSTI)

This research aimed at studying the spectral reflectance intensity of different exposed volcanic rocks in Syria, and drawing their curves by radiometer measurements. In order to reach this goal, we have studied different kinds of volcanic rocks related ...

M. Rukieh; A. M. Al-Kafri; A. W. Khalaf

2007-07-01T23:59:59.000Z

453

A cost modeling approach using learning curves to study the evolution of technology  

E-Print Network (OSTI)

The present work looks into the concept of learning curves to decipher the underlying mechanism in cost evolution. The concept is not new and has been used since last seven decades to understand cost walk down in various ...

Kar, Ashish M. (Ashish Mohan)

2007-01-01T23:59:59.000Z

454

A compact moduli space for Cohen-Macaulay curves in projective space  

E-Print Network (OSTI)

We define a moduli functor parametrizing finite maps from a projective (locally) Cohen-Macaulay curve to a fixed projective space. The definition of the functor includes a number of technical conditions, but the most ...

Hønsen, Morten Oskar, 1973-

2004-01-01T23:59:59.000Z

455

A Probabilistic Graphical Approach to Computing Electricity Price Duration Curves under Price and Quantity Competition.  

Science Conference Proceedings (OSTI)

The electricity price duration curve (EPDC) represents the probability distribution function of the electricity price considered as a random variable. The price uncertainty comes both from the demand side and the supply side, since the load varies continuously, ...

Pascal Michaillat; Shmuel Oren

2007-01-01T23:59:59.000Z

456

Multi-Factor Model of Correlated Commodity - Forward Curves for Crude Oil and Shipping Markets  

E-Print Network (OSTI)

An arbitrage free multi-factor model is developed of the correlated forward curves of the crude oil, gasoline, heating oil and tanker shipping markets. Futures contracts trading on public exchanges are used as the primary ...

Ellefsen, Per Einar

2009-01-01T23:59:59.000Z

457

Nondestructive method and apparatus for imaging grains in curved surfaces of polycrystalline articles  

SciTech Connect

A nondestructive method, and associated apparatus, are provided for determining the grain flow of the grains in a convex curved, textured polycrystalline surface. The convex, curved surface of a polycrystalline article is aligned in a horizontal x-ray diffractometer and a monochromatic, converging x-ray beam is directed onto the curved surface of the polycrystalline article so that the converging x-ray beam is diffracted by crystallographic planes of the grains in the polycrystalline article. The diffracted x-ray beam is caused to pass through a set of horizontal, parallel slits to limit the height of the beam and thereafter. The linear intensity of the diffracted x-ray is measured, using a linear position sensitive proportional counter, as a function of position in a direction orthogonal to the counter so as to generate two dimensional data. An image of the grains in the curved surface of the polycrystalline article is provided based on the two-dimensional data.

Carpenter, Donald A. (Lenior City, TN)

1995-01-01T23:59:59.000Z

458

Interplay of oxygen-evolution kinetics and photovoltaic power curves on the construction of artificial leaves  

E-Print Network (OSTI)

An artificial leaf can perform direct solar-to-fuels conversion. The construction of an efficient artificial leaf or other photovoltaic (PV)-photoelectrochemical device requires that the power curve of the PV material and ...

Surendranath, Yogesh

459

Floer cohomology in the mirror of the projective plane and a binodal cubic curve  

E-Print Network (OSTI)

We construct a family of Lagrangian submanifolds in the Landau-Ginzburg mirror to the projective plane equipped with a binodal cubic curve as anticanonical divisor. These objects correspond under mirror symmetry to the ...

Pascaleff, James Thomas

2011-01-01T23:59:59.000Z

460

p-ADIC HODGE THEORY Let C be a ?smooth curve over R ... - CECM  

E-Print Network (OSTI)

curve over R minus a divisor that is finite ?tale over R. Let p be a prime not dividing N. Let J be ?the Jacobian over C over R?, which will be an extension of the ...

Note: This page contains sample records for the topic "fatigue design curves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Model Development to Establish Integrated Operational Rule Curves for Hungry Horse and Libby Reservoirs - Montana, 1996 Final Report.  

DOE Green Energy (OSTI)

Hungry Horse and Libby dams have profoundly affected the aquatic ecosystems in two major tributaries of the Columbia River by altering habitat and water quality, and by imposing barriers to fish migration. In 1980, the U.S. Congress passed the Pacific Northwest Electric Power Planning and Conservation Act, designed in part to balance hydropower development with other natural resources in the Columbia System. The Act formed the Northwest Power Planning Council (Council) who developed a program to protect, mitigate and enhance fish and wildlife on the Columbia River and its tributaries. Pursuant to the Council`s Fish and Wildlife Program for the Columbia River System (1987), we constructed computer models to simulate the trophic dynamics of the reservoir biota as related to dam operation. Results were used to develop strategies to minimize impacts and enhance the reservoir and riverine fisheries, following program measures 903(a)(1-4) and 903(b)(1-5). Two FORTRAN simulation models were developed for Hungry Horse and Libby reservoirs located in northwestern Montana. The models were designed to generate accurate, short-term predictions specific to two reservoirs and are not directly applicable to other waters. The modeling strategy, however, is portable to other reservoir systems where sufficient data are available. Reservoir operation guidelines were developed to balance fisheries concerns in the headwaters with anadromous species recovery actions in the lower Columbia (Biological Rule Curves). These BRCs were then integrated with power production and flood control to reduce the economic impact of basin-wide fisheries recovery actions. These Integrated Rule Curves (IRCs) were developed simultaneously in the Columbia Basin System Operation Review (SOR), the Council`s phase IV amendment process and recovery actions associated with endangered Columbia Basin fish species.

Marotz, Brian; Althen, Craig; Gustafson, Daniel

1996-01-01T23:59:59.000Z

462

Load-curve responsiveness to weather and the cost-effectiveness of conservation  

SciTech Connect

A cost-benefit analysis of home-weatherization projects using average incremental power costs instead of peak or off-peak costs shows that some programs are no longer cost-effective. Weatherization improves the energy efficiency of houses and reduces demand on the utility, but a study of how monthly load curves at a Pacific Northwest utility responded to weather over a 12-month period indicates that abnormal weather shifts the entire load curve. 1 figure. (DCK)

Hellman, M.M.

1982-09-30T23:59:59.000Z

463

Asymptotic analysis of random matrices with external source and a family of algebraic curves  

E-Print Network (OSTI)

We present a set of conditions which, if satisfied, provide for a complete asymptotic analysis of random matrices with source term containing two distinct eigenvalues. These conditions are shown to be equivalent to the existence of a particular algebraic curve. For the case of a quartic external field, the curve in question is proven to exist, yielding precise asymptotic information about the limiting mean density of eigenvalues, as well as bulk and edge universality.

K. D. T-R McLaughlin

2006-10-20T23:59:59.000Z

464

Effects of neutron irradiation on fatigue and creep-fatigue crack propagation in type 316 stainless steel at 649 degree C produced no significant effect on the crack propagation rate when compared with unirradiated steel tested at 649 degree C  

Science Conference Proceedings (OSTI)

The fatigue and creep-fatigue crack propagation performance of Type 316 stainless steel has been investigated following fast neutron (n) irradiation. The purpose was to evaluate the effects of neutron fluence and temperature on the crack propagation resistance and failure mode of the steel. Results are presented from fatigue tests of the annealed steel that were irradiated at 649 degree C Scanning electron microscope examination of the fracture surfaces of the tested specimens revealed that the failure mode of the specimens which exhibited increased crack propagation rates was primarily intergranular while a transgranular mode was observed for specimens with lower crack propagation rates. The results point toward a synergistic relationship between thermomechanical history, precipitate formation, and hold time effects as the responsible mechanism for the crack propagation performance.

Michel, D.J.; Smith, H.H.

1981-01-01T23:59:59.000Z

465

Explicit solution by radicals, gonal maps and plane models of algebraic curves of genus 5 or 6  

Science Conference Proceedings (OSTI)

We give explicit computational algorithms to construct minimal degree (always =Keywords: Algebraic curves, Gonality, Plane models, Radical parametrisation

Michael Harrison

2013-04-01T23:59:59.000Z

466

Design and Analysis of the ITER Vertical Stability Coils  

SciTech Connect

The ITER vertical stability (VS) coils have been developed through the preliminary design phase by Princeton Plasma Physics Laboratory (PPPL). Final design, prototyping and construction will be carried out by the Chinese Participant Team contributing lab, Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). The VS coils are a part of the in-vessel coil systems which include edge localized mode (ELM) coils as well as the VS coils. An overview of the ELM coils is provided in another paper at this conference. 15 The VS design employs four turns of stainless steel jacketed mineral insulated copper (SSMIC) conductors The mineral insulation is Magnesium Oxide (MgO). Joule and nuclear heat is removed by water flowing at 3 m/s through the hollow copper conductor. A key element in the design is that slightly elevated temperatures in the conductor and its support spine during operation impose compressive stresses that mitigate fatigue damage. Away from joints, and break-outs, conductor thermal stresses are low because of the axisymmetry of the winding (there are no corner bends as in the ELM coils).The 120 degree segment joint, and break-out or terminal regions are designed with similar but imperfect constraint compared with the ring coil portion of the VS. The support for the break-out region is made from a high strength copper alloy, CuCrZr. This is needed to conduct nuclear heat to the actively cooled conductor and to the vessel wall. The support "spine" for the ring coil portion of the VS is 316 stainless steel, held to the vessel with preloaded 718 bolts. Lorentz loads resulting from normal operating loads, disruption loads and loads from disruption currents in the support spine shared with vessel, are applied to the VS coil. The transmission of the Lorentz and thermal expansion loads from the "spine" to the vessel rails is via friction augmented with a restraining "lip" to ensure the coil frictional slip is minimal and acceptable. Stresses in the coil, joints, and break-outs are presented. These are compared with static and fatigue allowables. Design for fatigue is much less demanding than for the ELM coils. A total of 30,000 cycles is required for VS design. Loads on the vessel due to the thermal expansion of the coil and spine are significant. Efforts to reduce these by reducing the cross section of the spine have been made but the vessel still must support loads resulting from restraint of thermal expansion.

Peter H. Titus, et. al.

2012-09-06T23:59:59.000Z

467

Space design  

Science Conference Proceedings (OSTI)

Space stations, Moon bases and Mars bases are artificial habitats intended to support human life in extreme conditions. Their purpose is to pursue human progress and to gain knowledge and experience of the environment surrounding our planet. This research ... Keywords: Human factors, Interior design, Space habitability, Sustainability, Vision

Irene Lia Schlacht; Henrik Birke

2011-06-01T23:59:59.000Z

468

Simulation System on the Thermal Stress and Fatigue Life Loss of Startup and Shutdown for a Domestic 600MW Steam Turbo Generator Unit  

Science Conference Proceedings (OSTI)

The Simulation System on the thermal stresses and fatigue life loss of the rotator during startup and shutdown for a domestic 600MW steam turbo generator unit, By means of the analysis of Simulation System on the thermal stress and life loss of the rotor, ... Keywords: steam turbine unit, thermal stress, Fatigue Life Loss, rotator, startup, shutdown

Yunchun Xia

2009-10-01T23:59:59.000Z

469

Fatigue damage estimate comparisons for northern European and U.S. wind farm loading environments  

DOE Green Energy (OSTI)

Typical loading histories associated with wind turbine service environments in northern Europe and within a large wind farm in the continental US were recently compared by Kelley (1995) using the WISPER [Ten Have, 1992] loading standard and its development protocol. In this study, an equivalent load spectrum for a US wind farm was developed by applying the WISPER development protocol to representative service load histories collected from two adjacent turbines operating within a large wind farm in San Gorgonio Pass, California. The results of this study showed that turbines operating in the California wind farm experience many more loading cycles with larger peak-to-peak values for the same mean wind speed classification than their European counterparts. In this paper, the impact of the two WISPER-protocol fatigue-load spectra on service lifetime predictions are used to compare and contrast the impact of the two loading environments with one another. The service lifetime predictions are made using the LIFE2 Fatigue Analysis Code [Sutherland and Schluter, 1989] with the fatigue properties of typical fiber glass composite blade materials. Additional analyses, based on rainflow counted time histories from the San Gorgonio turbines, are also used in the comparisons. In general, these results indicate that the WISPER load spectrum from northern European sites significantly underestimates the WISPER protocol load spectrum from a US wind farm site; i.e., the WISPER load spectrum significantly underestimates the number and magnitude of the loads observed at a US wind farm site. The authors conclude that there are fundamental differences in the two service environments.

Sutherland, H.J. [Sandia National Labs., Albuquerque, NM (United States). Wind Energy Technology Dept.; Kelley, N.D. [National Renewable Energy Lab., Golden, CO (United States). Wind Technology Div.

1995-05-01T23:59:59.000Z

470

Fatigue Crack Propagation from Notched Specimens of 304 SS in elevated Temperature Aqueous Environment  

DOE Green Energy (OSTI)

Fatigue crack propagation (FCP) rates for 304 stainless steel (304SS) were determined in 24 degree C and 288 degree C air and 288 degree C water using double-edged notch (DEN) specimens of 304 stainless steel (304 SS). Test performed at matched loading conditions in air and water at 288 degree C with 20-6- cc h[sub]2/kg h[sub]2O provided a direct comparison of the relative crack growth rates in air and water over a wide range of crack growth rates. The DEN crack extension ranged from short cracks (0.03-0.25 mm) to long cracks up to 4.06 mm, which are consistent with conventional deep crack tests. Crack growth rates of 304 SS in water were about 12 times the air rate. This 12X environmental enhancement persisted to crack extensions up to 4.06 mm, far outside the range associated with short crack effects. The large environmental degradation for 304 SS crack growth is consistent with the strong reduction of fatigue life in high hydrogen water. Further, very similar environmental effects w ere reported in fatigue crack growth tests in hydrogen water chemistry (HWC). Most literature data in high hydrogen water show only a mild environmental effect for 304 SS, of order 2.5 times air or less, but the tests were predominantly performed at high cyclic stress intensity or equivalently, high air rates. The environmental effect in low oxygen environments at low stress intensity depends strongly on both the stress ratio, R, and the load rise time, T[sub]r, as recently reported for austenitic stainless steel in BWR water. Fractography was performed for both tests in air and water. At 288 degree C in water, the fracture surfaces were crisply faceted with a crystallographic appearance, and showed striations under high magnification. The cleavage-like facets on the fracture surfaces suggest that hydrogen embrittlement is the primary cause of accelerated cracking.

Wire, G. L.; Mills, W. J.

2002-08-01T23:59:59.000Z

471

Effect of aging on the fatigue crack growth kinetics of an Al-Zn-Mg-Cu alloy in two directions  

Science Conference Proceedings (OSTI)

There have been investigations discussing the effect of aging condition, and thereby the microstructure, on the fatigue crack growth characteristics of precipitation hardening alloys. Lindigkeit et al.., testing an Al-Zn-Mg-Cu alloy of composition corresponding to the commercial alloy 7075 concluded that the crack propagation resistance of underaged microstructures with shearable precipitates is significantly higher than overaged samples of same strength containing non-shearable particles. They reported that this behavior cannot be explained on the basis of slip reversibility alone. A similar conclusion is drawn by Zaiken and Ritchie from investigations on the effect of microstructure on the fatigue crack growth rate of an 7150 aluminum alloy, which is a somewhat high-purity version of the alloy 7050, with lower Fe and Si contents. It is also interesting that aging conditions showing high resistance to fatigue crack growth at low [Delta]K regimes, do not necessarily retain their superiority at medium and high stress intensity ranges.

Alpay, S.P.; Guerbuez, R. (Middle East Technical Univ., Ankara (Turkey). Dept. of Metallurgical Engineering)

1994-02-15T23:59:59.000Z

472

NETL F 451.1/1-1, Categorical Exclusion Designation Form  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Burke West Lafayette, Indiana New Mechanistic Models of Creep-Fatigue Interactions for Gas Turbine Components To develop novel prediction tools for creep-fatigue crack growth in...

473

NETL F 451.1/1-1, Categorical Exclusion Designation Form  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Burke Corvallis, Oregon New Mechanistic Models of Creep-Fatigue Interactions for Gas Turbine Components To develop novel prediction tools for creep-fatigue crack growth in...

474

Corrosion fatigue of iron-chromium-nickel alloys: Fracture mechanics, microstructure and chemistry  

DOE Green Energy (OSTI)

Phase transformation and cracking during RT aging of charged, high-purity Fe18Cr12Ni alloy and commerical 304 ss were examined; results show that [epsilon]* (hcp) hydride formed on Fe18Cr12Ni upon charging, and it decomposed rapidly to form first [epsilon] and then [alpha]' martensite. Morphology of fracture surfaces of Fe18Cr12Ni produced by corrosion fatigue in NaCl solutions and in hydrogen was found to be identical. Effort was made to examine the approaches and methodologies used in service life predictions and reliability analyses.

Wei, R.P.

1993-01-25T23:59:59.000Z

475

KEPLER ECLIPSING BINARY STARS. III. CLASSIFICATION OF KEPLER ECLIPSING BINARY LIGHT CURVES WITH LOCALLY LINEAR EMBEDDING  

Science Conference Proceedings (OSTI)

We present an automated classification of 2165 Kepler eclipsing binary (EB) light curves that accompanied the second Kepler data release. The light curves are classified using locally linear embedding, a general nonlinear dimensionality reduction tool, into morphology types (detached, semi-detached, overcontact, ellipsoidal). The method, related to a more widely used principal component analysis, produces a lower-dimensional representation of the input data while preserving local geometry and, consequently, the similarity between neighboring data points. We use this property to reduce the dimensionality in a series of steps to a one-dimensional manifold and classify light curves with a single parameter that is a measure of 'detachedness' of the system. This fully automated classification correlates well with the manual determination of morphology from the data release, and also efficiently highlights any misclassified objects. Once a lower-dimensional projection space is defined, the classification of additional light curves runs in a negligible time and the method can therefore be used as a fully automated classifier in pipeline structures. The classifier forms a tier of the Kepler EB pipeline that pre-processes light curves for the artificial intelligence based parameter estimator.

Matijevic, Gal [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Prsa, Andrej [Department of Astronomy and Astrophysics, Villanova University, 800 E Lancaster Ave, Villanova, PA 19085 (United States); Orosz, Jerome A.; Welsh, William F. [Department of Astronomy, San Diego State University, 5500 Campanile Dr., San Diego, CA 92182 (United States); Bloemen, Steven [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Barclay, Thomas, E-mail: gal.matijevic@fmf.uni-lj.si, E-mail: andrej.prsa@villanova.edu [NASA Ames Research Center/BAER Institute, Moffett Field, CA 94035 (United States)

2012-05-15T23:59:59.000Z

476

A FOURIER OPTICS METHOD FOR CALCULATING STELLAR OCCULTATION LIGHT CURVES BY OBJECTS WITH THIN ATMOSPHERES  

Science Conference Proceedings (OSTI)

A stellar occultation occurs when a solar system object passes in front of a distant star. The light curves resulting from stellar occultations can reveal many aspects of the obscuring object. For airless bodies, the diffraction light curve specifies the object's size, distance and, if several chords are observed, shape. Occultation light curves are especially sensitive to the presence of atmospheres; the refraction light curve is a function of the atmosphere's density, pressure, and temperature profiles. The goal of this paper is to develop a practical algorithm to model the simultaneous effects of diffraction and refraction for objects in which both phenomena are observable. The algorithm we present is flexible: it can be used to calculate light curves by objects with arbitrary shapes and arbitrary atmospheres (including the presence of opacity sources such as hazes), provided that the atmosphere can be represented by a thin screen with a phase delay and an opacity defined at each location in the screen. Because the algorithm is limited at present to thin atmospheres (in which rays from a star are bent but undergo virtually no translation as they pass through an atmosphere), the gas giants, Earth, Mars, and Venus are not treated. Examples of stellar occultations are presented for round or irregularly shaped objects having thin atmospheres of various column densities.

Young, E. F., E-mail: efy@boulder.swri.edu [Southwest Research Institute, Department of Space Studies, Boulder, CO 80302 (United States)

2012-08-15T23:59:59.000Z

477

www.elsevier.com/locate/orms The learning curve: a new perspective  

E-Print Network (OSTI)

Despite the popularity of the ``learning' ' curve, it should be called the ``forecasting' ' curve. Given an industrial process, the traditional learning curve forecasts how costs are expected to decline (or other performance measures improve) in the future. Forecasting is certainly very useful. Nevertheless, the previous literature is notably mute on how the improvement or learning occurs. Without that information about how the process operates, the traditional learning curve cannot improve the rate of learning. This paper transforms the curve so that it not merely forecasts but rather actively creates the learning and knowledge. By extending work of the authors (Zangwill and Kantor, 1998), this paper constructs a new theoretical framework for learning and making improvements based upon learning cycles. This approach allows what is learned in one period to be intelligently applied to the next, improving the rate of learning right as production is occurring. Previous approaches could not do this. Because it should quickly increase the rate of learning, this approach might have important industrial

Willard I. Zangwill A; Paul B. Kantor