Abstract
A mismatch in material properties may cause a stress singularity, which leads to the failure of bonding in joints. It is important to analyze the stress singularity field for evaluating the strength of the interface in three-dimensional joints. Thermal residual stresses occur in a cooling process after bonding the joints at a high temperature, and the stress singularity for thermal stresses also occurs at an interface corner in the joints. In the present paper, a boundary element method and an eigenvalue analysis formulated using a finite element method are used for evaluating the intensity of singularity of the residual thermal stresses at a vertex in a joint. A three-dimensional boundary element program based on the fundamental solution for a two-phase isotropic body is used. The singular stress field for residual thermal stresses at the vertex in three-dimensional bonded structures with an interlayer is analyzed while varying the material properties of the interlayer. In addition, the relationship between Dundurs' parameter for three-dimensional stress states and the intensity of singularity is derived. In the present study, the stress singularity field is estimated for an arbitrary material combination investigated using this relationship under thermal loadings.
