THE APPROXIMATION BY 3-DIMENSIONAL ISOPARAMETRIC ELEMENT AND A KIND OF NUMERICAL INTEGRATION FORMAT OF 2ND ORDER DIRICHLET PROBLEM
二阶Dirichlet问题的三维等参元逼近及其数值积分格式

An approximation format of tetrahedral isoparametric element for solving the 3-dimensional 2-order Dirichlet problem is presented in this paper first,then based on the optical estima- tion of isoparametric transformation,we prove the convergence of the format given,obtain the optical H~1 estimate error.In order to simplify the complex computing of isoparametric element,we also construct a simple kind of numerical integration format,and its convergence is proved later.