skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: AN EVALUATION OF SEVERAL HARDENING MODELS USING TAYLOR CYLINDER IMPACT DATA

Abstract

No abstract prepared.

Authors:
;  [1]
  1. and others
Publication Date:
Research Org.:
Los Alamos National Lab., NM (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
764004
Report Number(s):
LA-UR-00-1192
TRN: AH200102%%83
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: COMPUTATIONAL METHODS IN APPLIED SCIENCES AND ENGINEERING, BARCELONA (ES), 09/11/2000--09/14/2000; Other Information: PBD: 1 Mar 2000
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; EVALUATION; HARDENING; IMPACT TESTS; MATHEMATICAL MODELS

Citation Formats

Zocher, M.A., and Maudlin, P.J. AN EVALUATION OF SEVERAL HARDENING MODELS USING TAYLOR CYLINDER IMPACT DATA. United States: N. p., 2000. Web.
Zocher, M.A., & Maudlin, P.J. AN EVALUATION OF SEVERAL HARDENING MODELS USING TAYLOR CYLINDER IMPACT DATA. United States.
Zocher, M.A., and Maudlin, P.J. 2000. "AN EVALUATION OF SEVERAL HARDENING MODELS USING TAYLOR CYLINDER IMPACT DATA". United States. doi:. https://www.osti.gov/servlets/purl/764004.
@article{osti_764004,
title = {AN EVALUATION OF SEVERAL HARDENING MODELS USING TAYLOR CYLINDER IMPACT DATA},
author = {Zocher, M.A. and Maudlin, P.J.},
abstractNote = {No abstract prepared.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2000,
month = 3
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • Taylor Cylinder impact testing is used to validate anisotropic elastoplastic constitutive modeling by comparing polycrystal simulated yield surface shapes (topography) to measured shapes from post-test Taylor impact specimens and quasistatic compression specimens. Measured yield surface shapes are extracted from the experimental post-test geometries using classical r-value definitions modified for arbitrary stress state and specimen orientation. Rolled tantalum (body-centered-cubic metal) plate and clock-rolled zirconium (hexagonal-close-packed metal) plate are both investigated. The results indicate that an assumption of topography invariance with respect to strain-rate is justifiable for tantalum. However, a strong sensitivity of topography with respect to strain-rate for zirconium was observed,more » implying that some accounting for a deformation mechanism rate-dependence associated with lower-symmetry materials should be included in the constitutive modeling. Discussion of the importance of this topography rate-dependence and texture evolution in formulating constitutive models appropriate for FEM applications is provided.« less
  • Taylor impact tests using specimens cut from a rolled plate of Ta were conducted. The Ta was well-characterized in terms of flow stress and crystallographic texture. A piece-wise yield surface was interrogated from this orthotropic texture, and used in EPIC-95 3D simulations of the Taylor test. Good agreement was realized between the calculations and the post-test geometries in terms of major and minor side profiles and impact-interface footprints.
  • The classic Taylor impact test imparts temporally and spatially varying fields of strain, strain rate, and temperature through the specimen. It is possible to exploit this complexity to directly identify constitutive model parameters from the deformed shape of the specimen. Where prior investigators have employed various mathematical fitting methods to identify or improve strength model parameters from Taylor cylinder profiles, we extend the method to employ a multi-objective genetic optimization algorithm to minimize the cylinder profile errors simultaneously on three cylinders impacted at different velocities. No experimental data other than the three Taylor cylinders is employed in developing the constitutivemore » model parameter set, and generic starting coefficients are employed. To validate the accuracy of the resulting coefficients, both split Hopkinson pressure bar and axisymmetric expanding ring tests were conducted and compared to the resultant Johnson-Cook strength model. The derived strength model agreed well with experimental data available to date. Further work is necessary to evaluate the range of rates and temperatures over which parameters derived by this method may be applied.« less
  • The Taylor test can be conveniently divided into three fairly distinct stages: (1) initial transient behavior after impact characterized by nonlinear plastic wave propagation. (2) quasi-steady propagation of the plastic wave front. The duration of this stage is a function of specimen caliber and material. (3) terminal transient behavior, during which most of the deceleration of the undeformed section takes place. After the initial transient is complete, which varies with the strain at which the plastic wave front propagates, the motion is well behaved, in the sense that a one-dimensional analysis can be effectively applied. This paper contains such anmore » analysis. Results are supported by an example from which the state of stress for an OFHC copper specimen is deduced.« less