FE modeling of thermo‐elasto‐plastic finite deformation and its application in sheet warm forming

In this paper, a strategy for analyzing a problem of the transient thermal coupling with the elastoplastic finite deformation is presented. A general constitutive equation is deduced by assuming the material properties to be temperature‐dependent. The thermal and mechanical coupling problem is solved with a staggered algorithm, which partitions the coupled problem into an elasto‐plastic problem at the known temperature field and a pure heat transfer problem at the fixed configuration. In this procedure, the elasto‐plastic mechanical analysis is based on the static‐explicit solution algorithm, which applies the finite deformation theory to describe the nonlinear behavior of the deformation body and its contact interaction with the tools during the forming process induced by the ordinary external loading and the “thermal loading”. In addition, both the ordinary heat transfer boundary conditions and the mechanical terms are taken into account in the implicit finite element analysis of the heat transfer. A special method based on the R‐minimum strategy is presented to solve the interaction problem between the static‐explicit mechanical analysis and the implicit thermal analysis. Furthermore, as examples, the analyses of sheet warm forming processes are demonstrated.