Finite element derivative recovery by moving least square interpolants

Abstract

A simple, accurate technique for recovery of displcements and derivatives, such as strains is presented. The technique is based on local interpolation of nodal displacements using a moving least square method. The strains are then recovered by taking appropriate derivatives of this interpolant. Numerical experiments in linear elasticity and heat conduction on the convergence and accuracy of the recovered derivatives show very good results and superconvergence for strains in many cases; the technique is also effective for displacement interpolation for projection methods.