Abstract: Numerical Manifold Method (NMM) with partially overlapping covers is a new type of NMM which uses independent covers to approach true physical field. Previous researches indicate that using small covers is a better approximation way than using big covers in the area with complex field distributions. Then we encounter the problem of connecting these small covers to their ambient big covers. In this paper we present a method of cover refinement for NMM with partially overlapping rectangular covers. It is easy to divide a big cover into some small covers and to connect these small covers to their ambient big covers in a compatible way, which is more convenient than NMM using FEM meshes in terms of transition between big meshes and small meshes. Two given examples, stress analysis of a gravity dam and computation of stress concentration factor of a circular hole, illustrate the validity of the method.

Key words: Numerical Manifold Method (NMM), partially overlapping covers, cover refinement, rectangular covers