Three-Dimensional Stress Analysis by Boundary Element Method using Fundamental Solution for Dissimilar Materials

Abstract

In recent years, composite materials and metal-ceramic joints have been used widely as industrial materials. Failure in these materials frequently occurs at the vicinity of bonded edges. It is therefore important to clarify the stress and displacement fields around the bonded edges. In this study, the authors first proposed the use of a triangle element for accurately analyzing a stress field with a singular line occurring along the section of interface and free surfaces in a three-dimensional bonded structure. The fundamental solution, including a boundary condition for the bonded interface (Rongved' solution) was next derived, and the stress distribution around the bonded edges was clarified by means of the three-dimensional boundary element method using this solution. It was found that the order of the stress singularity of three-dimensional dissimilar materials is between that of plane strain and plane stress, and that as an internal point approaches the free surface along the bonded edge, the order of stress singularity approaches that of the plane stress. The order of stress singularity was investigated in the spherical coordinate system with the origin at the bonded edge. The order is constant in all directions, and is larger than those for plane strain and for plane stress. When the apex angle of the bonded edge is changed to an angle incurring no stress singularity in plane strain or plane stress, the stress singularity vanishes in three-dimensional dissimilar materials. © 1993, The Japan Society of Mechanical Engineers. All rights reserved.