On the choice of the linear element for corotational triangular shells

The corotational formulation for triangular thin shell elements presented in [A. Eriksson, C. Pacoste, Element formulation and numerical techniques for stability problems in shells, Comput. Methods Appl. Mech. Engrg. 191 (2002) 3775–3810] is further developed in order to incorporate elasto-plastic deformations. Several local formulations are implemented and tested. These local elements are geometrically linear and are obtained by the by superposition of a membrane and a plate part. Eleven elastic and elasto-plastic examples are presented. Both the incremental and deformation theories of plasticity are considered. The first objective is to assess the performance of the present formulation in modelling elasto-plastic instability problems. The second objective is to compare the different linear local formulations: it is shown that some of them give better results in instability problems.