EXTRACTION OF HIGHER DERIVATIVES IN FEM FOR POISSON EQUATION AND THE PLANE ELASTICITY PROBLEM
泊松方程及平面弹性问题有限元方法中求高阶导数的提取法

This paper gives extraction formulae for higher derivatives of solutions of thePoisson equation and the plane elasticity problem. With these formulae the approxi-mation of higher derivatives of solution obtained from the finite element solutionhas the same order of accuracy as for the approximate solution itself. These resultscan be used in a-posteriori error estimates and the adaptive finite element methods.