An efficient eight-node incompatible solid element with stress interpolation

Abstract

A new eight-node solid element based on Hellinger-Reissner's energy functional modified by constant stress multipliers is presented. To ensure frame invariance, isoparametric coordinates are adopted in the interpolation of both stresses and displacements. Besides possessing the minimum number of stress parameters needed to avoid the occurrence of zero energy deformation modes, the eight-node element exhibits a low distortion sensitivity. Selected examples providing a broad range of analytical stress and displacement distributions are used to examine the performance of the element. Numerical results show that the element being suggested yields good predictions for both displacements and stresses when compared with other three-dimensional elements.