Comparative study of constitutive and finite element formulations for large strain elastoplasticity

This paper presents a comparative study of the different formulations used in research groups in Liège and Mendoza, for the modelling of large plastic deformations. The comparison focused on a few academic standardized problems. We analysed both the constitutive formulation (strain-stress relations) and the finite element formulation (discretized mechanical balance equations). In particular, we compared two constitutive formulations, both hyperelastic, but resulting from different theoretical approaches. We also compared different types of finite elements (4-noded quadrangles and 6-noded triangles), in axisymmetric and plane strain settings. These comparisons show that both approaches yield very similar results. Computations also show that models based on 6-noded triangles give good results. The only limitation suggested by the results obtained is that triangles appear to be more sensitive to large distorsions than quadrangles