Analysis of sandwich plates: A three-dimensional assumed stress hybrid finite element

An eight-node assumed stress solid element with rotational degrees of freedom is employed for analyses of sandwich plates consisting of stiff face and a comparatively flexible core material with the aim to accurately and efficiently capture stresses. The element formulation is based directly on an eight-node element. This direct formulation requires fewer computations than a similar element that is derived from an internal 20-node element in which the midside degrees of freedom are eliminated by expressing them in terms of displacements and rotations at corner nodes. The formulation is based on Hellinger-Reissner variational principle. Numerical examples are presented to show the validity and efficiency of the present element.