Hybrid finite elements for the computation of sandwich plates

In this article, new hybrid finite elements are developed on the basis of the displacements and the Pian and Tong functionals using Lagrange multipliers in order to compute correctly and efficiently interlaminar stresses in sandwich structures. These elements represent the mechanical behaviour of sandwich structures in an accurate way, especially at interfaces, where the force equilibrium state must be ensured. They permit to obtain the values of interlaminar stresses using a coarse mesh through the thickness of the sandwich structure. These hybrid elements are assessed and compared through several examples of static linear problems with solutions found in the literature.