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Title: Combining Orientation Mapping and In-situ TEM to Investigate High-Cycle Fatigue and Failure.

Abstract

Abstract not provided.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1373637
Report Number(s):
SAND2016-7274C
Journal ID: ISSN 1431--9276; 646203
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Journal Volume: 22; Journal Issue: S3; Conference: Proposed for presentation at the Microscopy & Microanalysis held July 25-29, 2016 in Columbus, OH.
Country of Publication:
United States
Language:
English

Citation Formats

Bufford, Stauffer, Douglas, Mook, William, Syed, S.A., Boyce, Brad Lee, and Hattar, Khalid Mikhiel. Combining Orientation Mapping and In-situ TEM to Investigate High-Cycle Fatigue and Failure.. United States: N. p., 2016. Web. doi:10.1017/S1431927616009521.
Bufford, Stauffer, Douglas, Mook, William, Syed, S.A., Boyce, Brad Lee, & Hattar, Khalid Mikhiel. Combining Orientation Mapping and In-situ TEM to Investigate High-Cycle Fatigue and Failure.. United States. doi:10.1017/S1431927616009521.
Bufford, Stauffer, Douglas, Mook, William, Syed, S.A., Boyce, Brad Lee, and Hattar, Khalid Mikhiel. 2016. "Combining Orientation Mapping and In-situ TEM to Investigate High-Cycle Fatigue and Failure.". United States. doi:10.1017/S1431927616009521. https://www.osti.gov/servlets/purl/1373637.
@article{osti_1373637,
title = {Combining Orientation Mapping and In-situ TEM to Investigate High-Cycle Fatigue and Failure.},
author = {Bufford and Stauffer, Douglas and Mook, William and Syed, S.A. and Boyce, Brad Lee and Hattar, Khalid Mikhiel},
abstractNote = {Abstract not provided.},
doi = {10.1017/S1431927616009521},
journal = {},
number = S3,
volume = 22,
place = {United States},
year = 2016,
month = 7
}

Conference:
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  • A procedure has been developed to determine the cumulative fatigue damage in structures experiencing complicated multi-axial stress histories. The procedure is a generalization of the rainflow method developed by Matsuishi and Endo for one-dimensional situations. It provides a consistent treatment of three-dimensional stress states that is especially suited to computer programming applications for the post-processing of finite element stress data. The procedure includes a unique method to account for the rotation of principal stresses with time during the stress history and for the cumulative fatigue damage resulting from partial stress reversals within a stress cycle. The general procedure and necessarymore » equations for programming are presented. Comparisons are made with life predictions using Section III of the ASME Boiler and Pressure Vessel Code for two hypothetical multi-axial stress histories for which the principal stresses are rotating with time. These comparisons show that the cycle counting method provides a consistent unambiguous interpretation of the fatigue design procedure in the ASME Code for these cases. Finally, the fatigue life of a perforated plate, as analyzed by finite elements, is computed for the combination of several hypothetical stress histories. This example demonstrates the utility of the proposed method when used in conjunction with finite element programs.« less
  • Damage progress in toughened-type CFRP cross-ply laminates under tensile fatigue loading was measured by the replica technique. The damage parameters, the transverse crack density and the delamination ratio, were presented. Based on above data, simple shear-lag analysis combined with the modified Paris law model was conducted to model the damage progress. In addition, a novel power-law model was proposed, which related the cyclic strain range and the number of cycles. The loading-unloading tests were also performed to obtain the Young`s modulus reduction and the permanent strain as functions of the damage state. The shear-lag predictions of the Young`s modulus reductionmore » and the permanent strain showed good agreement with the experimental data, when the interaction between transverse cracking and delamination were taken into account.« less
  • High-cycle data were generated on Materials Test System (MTS) closed-loop electrohydraulic fatigue machines operating in the push-pull sinusoidal-load waveform mode at a frequency of 40 Hz. All tests were in air on hourglass specimens which had a minimum diameter of 0.125 inch. Three Incoloy heats were evaluated and contained the following concentrations of carbon, titanium, and aluminum: Heat HH5556A--0.07% C, 0.42% Ti, 0.47% Al; Heat HH3113A--0.06% C, 0.39% Ti, 0.36% Al; and Heat HH7531A--0.03% C, 0.20% Ti, 0.10% Al. Data on the latter low-carbon heat are given for comparison only and were not included in the analysis.
  • An analytical procedure has been evaluated to determine whether low and high cycle fatigue testing techniques may be correlated in the 10/sup 5/ cycle region where the data overlap. The procedure, which is based on the use of cyclic stress-strain curves to convert high cycle fatigue stresses to equivalent strains, is shown to be acceptable for Incoloy 800H, Hastelloy X, Type 304 stainless steel and 2 1/4 Cr--1Mo steel in the range of temperature for which data are available.
  • Fatigue analysis is an important aspect of understanding mechanical properties of metals and alloys. It is well known that the temperature of a specimen during cyclic fatigue testing increases as a result of internal friction. The temperature changes of a specimen are usually obtained using a thermocouple, but such measurements only provide temperature readings at a specific location. On the other hand, a detailed temperature distribution map of the specimen obtained during fatigue tests could be used as a new dynamic method of monitoring crack initiation and propagation behavior. Temperature changes during fatigue tests are expected to be local andmore » in the form of thermal transients. Capturing thermal signatures associated with fatigue cracks requires a high-speed, high-sensitivity infrared imaging system. Relevant studies using a scanning infrared camera (IR) with temperature resolution of 0.1 K at 293 K can be found in the literature. In the present study, a state-of-the-art IR camera was employed to monitor temperature changes of ULTIMET* alloy during high-cycle fatigue tests. Using the snap-shot and the sequence modes of the IR camera, temperature distribution maps of the specimen as a function of time (cycles) have been obtained. This work reports temperature changes during high-cycle fatigue tests and infrared imaging of fatigue cracks as a heat source before the final failure.« less