Built-in field equations for recovery procedures

A novel local polynomial representation for the unknown function and the corresponding derivative quantitites of interest, which contains ''built-in'' information from the field equations, is presented. This local representation can be used in connection with element (by element) or patch (by patch) recovery procedures. A patch recovery technique, which uses this local representation to get improved global, C-0-continuous, smoothed finite element approximations for the derivative quantities (such as gradient components or strains) from the results of standard finite element anlaysis, is developed. Two model problems, the so-called quasi-harmonic equation and the plane elasticity problem, are considered. (C) 1997 Civil-Comp Ltd and Elsevier Science Ltd.