Error estimation with postprocessed finite element solutions

The superconvergent patch recovery (SPR) technique and its enhancements has been shown to be an accurate and efficient method to obtain an improved solution. It gives a more accurate solution and it can be utilized for an error estimation of the finite element solution. The improved solution often has at least one order higher convergence rate and is much more accurate than the finite element solution. The paper gives a review of different aspects and enhancements of the SPR-technique and proposes an additional global iteration procedure, which gives an even higher accuracy. These changes make it possible to give an error estimation of the improved solution. The different error estimations are used in an adaptive process, showing that improved error estimation gives improved adaptivity performance. (C) 1997 Civil-Comp Ltd and Elsevier Science Ltd.