An element stress recovery technique with equilibrium constraint for superconvergent boundary stress extraction

摘要

An element stress recovery technique is proposed for accurate boundary stress extraction. ^Equilibrium constraint is imposed using two residuals of equilibrium in variational forms. ^A higher-order stress field is assumed only for a selected stress component; other components are assumed to be as high as the order of the assumed displacement in the finite element used for analysis. ^The recovery stress fields are assumed within an element. ^By employing these features, the final matrix to be inverted becomes well-conditioned. ^Numerical examples demonstrate that quite accurate boundary stresses can be recovered even for coarse meshes by means of this method. ^It is also shown that the method can extract accurate boundary stresses without implementing superconvergent stresses. ^The present method should be very effective for localized boundary stress extraction. ^(Author)