Finite element analysis using an incremental elasto-visco-plastic self-consistent polycrystal model: FE simulations on Zr and low-carbon steel subjected to bending, stress-relaxation, and unloading

The Delta EVPSC model is a general elasto-visco-plastic self-consistent constitutive formalism based on a Homogeneous Effective Medium (HEM) approach that accounts explicitly for microstructural features such as slip, twinning, and crystallographic texture. Delta EVPSC is improved with respect to the original model reported in (Jeong and Tome, 2020) by introducing an intermediate linearization scheme, which leads to better predictive accuracy of intergranular stress and strain distributions in the polycrystal. The Delta EVPSC model is interfaced with a commercial finite element solver Abaqus/standard as a user-defined material subroutine (Delta EVPSC-FE). Delta EVPSC-FE shows superior numerical stability and, when using parallel computation and 40 CPU core units, it reduces the computation time by a factor 20 compared to using a single CPU core unit for a structure consisting of 512 solid elements. The Delta EVPSC-FE model is applied to FE analyses of Zr and low-carbon steel bars subjected to a sequence of bending, stress-relaxation, and unloading. It is shown that the hereditary effect is responsible for the spring-forward motion during the early stage of unloading, while the elastic recovery mainly drives the subsequent spring-back.

Automated summary

The Delta EVPSC model is a general elasto-visco-plastic self-consistent constitutive formalism based on a Homogeneous Effective Medium (HEM) approach. By introducing an intermediate linearization scheme, it achieves more accurate predictions of intergranular stress and strain distributions in polycrystals. The Delta EVPSC-FE model offers superior numerical stability and reduced computation time, making it suitable for finite element analyses of metallic materials.