Extension of the solid-shell concept for application to large elastic and large elastoplastic deformations

In the present contribution we extend a previously proposed so-called solid{shell concept which incorporates only displacement degrees of freedom to the simulation of large elastic and large elastoplastic deformations of shells. Therefore, the modi cations necessary for hyper-elastic or elastoplastic material laws are discussed. These modi cations concern the right Cauchy{Green tensor for large elastic deformations, respectively, the deformation gradient for elastoplasticity which then are consistent to the modi ed Green{Lagrange strains that are necessary for transverse shear and membrane locking free solid{shell element formulations. However, in addition to the locking mentioned above especially in the range of plasticity incompressibility locking becomes important. Thus, the second major aspect of this contribution is the discussion of several ways to avoid incompressibility locking also including the investigation of eigenmodes. Finally, a selective reduced integration scheme with reduced integration for the volumetric term is employed and described in detail, although it is limited to material laws which allow the decomposition into a volumetric and a deviatoric part. Some numerical examples show the range of application for the proposed elements.