Error estimation based on Superconvergent Patch Recovery using statically admissible stress fields

In this paper we investigate an approach for a posteriori error estimation based on recovery of an improved stress eld. The qualitative properties of the recovered stress eld necessary to obtain a conservative error estimator, i.e. an upper bound on the true error, are given. A speci c procedure for recovery of an improved stress eld is then developed. The procedure can be classi ed as Superconvergent Patch Recovery (SPR) enhanced with approximate satisfaction of the interior equilibrium and the natural boundary conditions. Herein the interior equilibrium is satis ed a priori within each nodal patch. Compared to the original SPR-method, which usually underestimates the true error, the present approach gives a more conservative estimate. The performance of the developed error estimator is illustrated by investigating two plane strain problems with known closed-form solutions