A superconvergent stress recovery technique for accurate boundary stress extraction

An element-base superconvergent stress recovery technique is developed for accurate boundary stress extraction. In the present method, higher-order stress "elds are assumed for all stress components and higher order elements are used for the construction of necessary matrices. Unknown coe$cients for the assumed stress "eld are obtained by minimizing the sum of the stress errors and two equilibrium residuals in the least squares sense. The two residuals are derived based on the principle of virtual work. Numerical examples including a three-dimensional problem have demonstrated that the present method can stably extract very accurate boundary stresses even for coarse meshes.