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

• Published in: International journal of plasticity 2021-12, Vol.147, p.103110, Article 103110
• Main Authors: Jeong, Youngung, Jeon, Bohye, Tomé, Carlos N.
• Format: Article
• Language: English
• Subjects: Bending; Computation; CP-FE; Crystallography; Elastic recovery; elasto-visco-plastic modeling; Finite element method; Low carbon steel; Low carbon steels; Mathematical models; Numerical stability; Parallel processing; Polycrystals; spring-back; spring-forward; Stress relaxation; texture; Zirconium
• ISSN: 0749-6419; 1879-2154
• DOI: 10.1016/j.ijplas.2021.103110

•The incremental elasto-visco-plastic self-consistent formulation is improved.•HEM-based elasto-visco-plastic self-consistent formulation has been interfaced with an implicit FE code for the first time.•ΔEVPSC is applied for hexagonal crystal structure with twinning for the first time.•FE bending simulation of Zr and low-carbon steel bars are demonstrated.•Spring-forward is captured after stress-relaxation that is followed by spring-back. The ΔEVPSC 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. ΔEVPSC is improved with respect to the original model reported in (Jeong and Tomé, 2020) by introducing an intermediate linearization scheme, which leads to better predictive accuracy of intergranular stress and strain distributions in the polycrystal. The ΔEVPSC model is interfaced with a commercial finite element solver Abaqus/standard as a user-defined material subroutine (ΔEVPSC-FE). ΔEVPSC-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 ΔEVPSC-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.