A convenient evaluation of intensity of singular stress field at the interface corner in single lap joint with fillet

Abstract

In this paper, a convenient evaluation of an intensity of singular stress field (ISSF) at an interface corner in a single lap joint (SLJ) with a fillet is examined. The analysis method is focused on the ratio of the stress values at the interface corner obtained by applying the finite element method (FEM) to the SLJ model and the reference model which are subdivided by the same mesh pattern. It is shown that the square-shaped inclusions in the infinite plate under bi-axial uniform stress and pure shear stress can be analyzed by the reciprocal work contour integral method and are suitable for the reference model. The numerical simulations are performed on the SLJs with the fillet which are composed of the steel adherend and the epoxy adhesive. It is confirmed that the ISSF for the SLJ with the fillet can be evaluated conveniently and accurately by comparing the asymptotic solution with the FEM stress distributions. Then, the critical ISSF values are calculated from the experimental results of the SLJs with the fillet having overlap length L = 12.5, 20, 25, 40, 60mm in the earlier study. When L ≥ 40mm, the fracture occurred from interface corner, in which case it is shown the critical ISSF values are constant independent of L.

Keywords

• single lap joint
• fillet
• interface
• intensity of singular stress field
• finite element method