Analysis for stress singularity field at a vertex in three-dimensional bonded structures

In the present paper, the order of stress singularity at the corner where f our free surfaces and interfaces in three-dimensional joints meets is inves tigated by solving an eigenequation derived from a finite element formulati on. The order of stress singularity for three typical joints, referred to a s the 1/8-1/8, 1/8-1/4 and 1/8-1/2 joints, between two rectangular blocks w ith different properties is investigated and compared with that of two-dime nsional joints with the same cross section as that of the three-dimensional joints. Dundurs' composite parameters, alpha(3D) and beta(3D), for three-d imensional joints are newly introduced and the order of stress singularity plotted on ordinal Dundurs' parameters, the alpha and beta plane, is rearra nged on the alpha(3D) - beta(3D) plane. The order of stress singularity at the vertex in the three-dimensional joints is larger than that in the two-d imensional ones, although, the boundary at which the stress singularity van ishes varies little on the alpha(3D) - beta(3D) plane. Furthermore, it is s hown that the order of stress singularity at a vertex, where same singular lines with different orders meet, varies with the combination of material p roperties.