Numerical study on the hot compression test for bulk metal forming application

In this study, a comparison between the well-established Lagrangian approach and the Arbitrary Lagrangian–Eulerian (ALE) approach is presented. This comparison aims to verify the ALE's approach suitability for modeling thermomechanical processes. After that, a study on the material's stress state evolution inside the specimen is provided. The stress state is evaluated through the triaxiality factor and Lode parameter. Ideally, under pure compression, these parameters' values are − 1/3 and − 1, respectively. However, it is not possible to achieve ideal conditions in actual experiments. The Lagrangian model was done in QForm, and the ALE model was done in LS-Dyna. The results from both models are in good agreement between them and agree with the force vs. stroke measured during the experiments. Two paths were defined to study the stress state inside the sample, in the radial direction (equator line) and axial direction (axial line). It was concluded that some areas in both paths might be considered as approximately under pure compression stress state. In addition, the ALE approach accuracy for thermomechanical modeling was verified.