Non-linear analysis of sandwich shells: the effect of core plasticity

A non-linear formulation for general, arbitrary, sandwich shells is presented. The formulation accounts for geometric and material non-linear behavior of the shell. The core plasticity is assessed. The first order shear deformation theory is presented as far as the kinematics are concerned. The analysis is based on the displacement formulation of the finite element method and uses the Ahmad shell element with five degrees of freedom per node. The approach is discussed, particularly with reference to a cylindrical shell subjected to transverse load that causes snap buckling.