Intensity of Singular Stress Field Distributions along Interface for 3D Butt Joint

Our previous study showed that the debonding condition of butt joints can be expressed as a constant value of the intensity of singular stress field (ISSF) by using 2D FEM model. To consider the real state of stress, in this paper, the ISSF distributions along the interface are shown for 3D butt joint model by varying the adhesive thicknesses. Here, the mesh-independent technique proposed in the previous study is applied to evaluate the ISSF of 3D FEM model. Then, the ISSF is found to be constant along about 90% of the middle region of the side interface. The ISSF increases rapidly in the vicinity of the vertex region. It is found that the critical ISSF values are almost the same independent of the adhesive thickness at the middle region of the side interface and at the vertex in 3D butt joint.