THE BOUNDARY EXPANDING-CONTRACTING METHOD

The boundary element method(BEM)which a used to solve the elastic problems has more advantages than other numerical methods.Especially,it can resolve rapidly varying internal stress and strain fields more accurately.However,it is of ten fails in the region near the boundary because of the singularity of the solutions.Though we can increase the boundary meshes more and more,the solutions of stress on the boundary can‘t be given directly;which has obstructed the applications of the BEM to some extent.In this paper we proposed the boudary expanding-contracting principle and the boundary expanding-contracting method(BECM)based on the principle.With this method,not only the solutions in the region near or on the boundary can be obtained directly,but the iterative processes can also be used conveniently to improve the accuracy of the solutions.