SUPERCONVERGENCE AND THE SUPERCONVERGENT PATCH RECOVERY

In this note we show that the SPR procedure (Superconvergent Patch Rec overy) introduced by Zienkiewicz and Zhu (Int. J. Numer. Methods Eng. 33, pp. 1331-1364, 1992; 33, pp. 1365-1382, 1992; Comput. Methods Appl . Mech. Eng. 101, pp. 207-224, 1992) yields superconvergent stress/gra dient values throughout the domain when based on sample points with kn own superconvergent properties. Further we show that for elements such as triangles where superconvergent points do not exist, certain sampl ing procedures still result in superconvergence of recovered values. W e also indicate why some other recovery processes give poor performanc e.