To obtain an accurate solution with the Finite Elemnent method, controling parameters are displacement functions and mesh grids. Recently, higher order displacement functions have been developed. One of the representative elements is isoparametric elements. On the other hand, there is a few research work available on a reasonable mesh grids for a given problem.
　This study dicusses a relationship between an accuracy of a calculated solution and mesh grids. Numerical examples show dependency of a solution on total degrees of freedom and elements distributions. Guide line is proposed through these numerical examples. It is verified that optimum mesh grid based on isoenergetics is very effective.