Improving computational efficiency and stability of material models for finite element analyses of metal powder compaction

We developed a material user-subroutine in commercial finite element (FE) package ABAQUS/EXPLICIT for the Drucker-Prager Cap material model. Two techniques to improve the stability and one to improve the computational efficiency were proposed and proven to be successful. To improve stability (1) an iterative technique to determine the increment size was introduced, and (2) a corner region was implemented for the first time in an explicit FE code. (3) The computational efficiency was improved by a simplification in the computational plasticity formulation; it was shown that this technique significantly decreases the computational cost by slightly sacrificing the accuracy. These techniques were tested in separate case studies. The results were compared to experimental measurements in literature for a two-level part.