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Constitutive modeling for isotropic materials (HOST)The results of the first year of work on a program to validate unified constitutive models for isotropic materials utilized in high temperature regions of gas turbine engines and to demonstrate their usefulness in computing stress-strain-time-temperature histories in complex three-dimensional structural components. The unified theories combine all inelastic strain-rate components in a single term avoiding, for example, treating plasticity and creep as separate response phenomena. An extensive review of existing unified theories is given and numerical methods for integrating these stiff time-temperature-dependent constitutive equations are discussed. Two particular models, those developed by Bodner and Partom and by Walker, were selected for more detailed development and evaluation against experimental tensile, creep and cyclic strain tests on specimens of a cast nickel base alloy, B19000+Hf. Initial results comparing computed and test results for tensile and cyclic straining for temperature from ambient to 982 C and strain rates from 10(exp-7) 10(exp-3) s(exp-1) are given. Some preliminary date correlations are presented also for highly non-proportional biaxial loading which demonstrate an increase in biaxial cyclic hardening rate over uniaxial or proportional loading conditions. Initial work has begun on the implementation of both constitutive models in the MARC finite element computer code.
Document ID
19900004075
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Lindholm, Ulric S. (Southwest Research Inst. San Antonio, TX., United States)
Chan, Kwai S. (Southwest Research Inst. San Antonio, TX., United States)
Bodner, S. R. (Southwest Research Inst. San Antonio, TX., United States)
Weber, R. M. (Pratt and Whitney Aircraft East Hartford, CT., United States)
Walker, K. P. (Southwest Research Inst. San Antonio, TX., United States)
Cassenti, B. N. (Southwest Research Inst. San Antonio, TX, United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1984
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
NAS 1.26:174718
NASA-CR-174718
SWRI-06-7576/13
Accession Number
90N13391
Funding Number(s)
CONTRACT_GRANT: NAS3-23925
PROJECT: RTOP 533-04-1A
PROJECT: SWRI PROJ. 06-7576
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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