Performance of Tri-Adhesive Joints to Improve the Shear Stress Distribution of Lap Joints

Abstract

The adhesive lap joints are extensively used in various engineering fields. Various methods were proposed to increase the strength of the lap joint. This paper presents the lap joint's characterization by applying three grades of adhesives in different material properties along the bond line. The stiffest adhesive is employed in the middle bond line, then gradually, those with a lower modulus of elasticity are placed at the ends of the lap joint. This technique reduces the stress concentration at the joining ends, so the stress distribution becomes smoother. Finite element analysis is used to model this problem in two dimensions. One of the adherent edges is applied to the fixed support, and the other end is subjected to tension. The analysis results show that the use of tri-adhesive changes the shear stress distribution along the bond line flatter and increases the strength of tri-adhesive lap joints compared to those single type adhesive applied individually.