Large inelastic strain analysis by multilayer shell elements

Summary The objective of this contribution is to model large inelastic strains of ductile metals, to couple this material model with a multilayer shell kinematics and finally to achieve a finite element formulation applicable in general form to shell analysis. Elasto-plastic constitutive law is formulated by using the multiplicative decomposition of the deformation gradient and Neo-Hookean model for elastic strains assuming an overall isotropic material behavior. These 3D-material model is then enforced directly into a multilayer shell kinematics which provides a very accurate consideration of local effects, particularly stresses across the thickness. Finite element formulation is accomplished by means of the enhanced strain concept. Thus the well known deficiencies due to incompressible deformations and the inclusion of transverse strains are avoided. Several examples are given to demonstrate the performance of the algorithms developed concerning various aspects.