Development and Evaluation of an Uncoupled, Incremental Constitutive Model for Elastic-Plastic-Creep Behavior at Elevated Temperatures

摘要

The purpose of this research is to extend the classical incremental theory of plasticity to develop and evaluate the uniaxial constitutive relations necessary to model the nonlinear behavior of crystalline materials experiencing thermoelastic-plastic-creep. Among the requirements for a sound constitutive theory for the media mentioned above are that it incorporate the ability to model transient temperature response; cyclic behavior including cyclic saturation, the change in strain hardening upon stress reversal, and the Bauschinger effect; and rate dependence. In fulfillment of these objectives, this thesis will proceed in the following manner. First, a brief literature review of the available theories is presented along with a discussion of the details of the constitutive model used in this research. Next, the development of the model is accomplished by derivation of the uniaxial theory including experimental data requirements and computational considerations. Several theoretical examples are presented along with comparison to experiments on several different metals at elevated temperature.