Finite Element Thermoelastoplastic Analysis

A technique is presented for obtaining the elastic-plastic stress-strain distribution in axisymmetric and plane stress continuum composed of temperature dependent linear strain-hardening isotropic material. The method employs an incremental finite element computer program using the Prandtl-Reuss flow equations to derive a plastic stress-strain matrix in a manner similar to the tangent modulus method. The addition of pseudo stresses is used to develop load terms that account for changes in the material properties which occur during the increment, thus keeping the solution on the temperature dependent material stress-strain curve. The pseudo stresses also correct for any elastic over-shoot that occurs when an element changes from an elastic to a plastic state. With this technique it becomes economically feasible to perform elastic-plastic stress analyses on two-dimensional continuum subjected to transient thermal and mechanical loadings with material properties varying during multiple loading-unloading cycles.