A “Prism” solid element for large strain shell analysis

In this paper a triangular prism solid element for the analysis of thin/thick shells undergoing large elastic–plastic strains is developed. The element is based on a total Lagrangian formulation and uses as strain measure the logarithm of the right stretch tensor (U) obtained from a modified right Cauchy–Green deformation tensor ( C ¯ ). Three are the introduced modifications: (a) a classical assumed strain approach for transverse shear strains (b) an assumed strain approach for the in-plane components using information from neighbor elements and (c) an averaging of the volumetric strain over the element. The objective is to use this type of elements for the simulation of shells avoiding transverse shear locking, improving the membrane behavior of the in-plane triangle and to handle quasi-incompressible materials or materials with isochoric plastic flow. Several examples are presented that show the transverse-shear locking free behavior, the importance of the improvement in the membrane approach and the wide possibilities of the introduced element for the analysis of shell structures for both geometric and material non-linear behavior.