A layered shell element for the computation of interlaminar shear stresses and thickness normal stresses

Abstract

In this contribution a layered shell element for the computation of laminated structures is proposed. The shell kinematic is based on the Reissner-Mindlin theory with an inextensible director field. Further a multi-field functional is introduced including the global shell equations and additional Euler-Lagrange equations. These Euler-Lagrange equations enforce the correct shape of warping through the thickness and lead to continuous transverse shear stresses at layer boundaries This leads to a mixed hybrid shell element, after elimination of stresses, warping and Lagrange parameters on element level. The resulting shell element has the usual 5 or 6 degrees of freedom per node, making it possible to apply this element to complex geometrical structures. An extension of the element to compute stresses in thickness direction is shown, in order to estimate and predict interlaminar failure. The computed results show good agreement with 3D solid shell models. Numerical examples for the computation of interlaminar shear and thickness normal stresses are shown and compared to results of 3D elements.