The effect of co-creation of notches and recesses in the adhered material on the strength of single-lap adhesive joints: Experimental and numerical analysis

Since the 1980s, many different adhesive joint geometries have been used in aerospace and automotive applications, with the idea that adhesively-bonded joints can be an alternative to traditional joining methods in aerospace applications. One of the joint geometries frequently used today is the single-lap joint geometry. In this joint geometry, due to eccentric loading, peel stresses occur, which cause damage in the overlap region. Reducing these stresses increases joint strength. In this study, the strengths of single-lap joints (SLJ) obtained by creating notches and recesses of different lengths and depths in the adhered material were investigated experimentally and numerically. In the study, the DP460 structural adhesive was used as the adhesive, and the AA2024-T3 aluminum alloy was used as the adherend. First, the strengths of the SLJ obtained by using different lengths and thicknesses of recesses and notches of different widths and depths in the adherend were investigated. Then, the best recessed or protruding joints obtained in terms of joint strength were determined, and the joint strengths with the best both recess and protrusion geometry were examined. As a result, making a recess of the adherend on the outer part of the overlap region in single-lap joints increases the joint strength by approximately 29%, and making a notch increases the strength of the connection by approximately 27%. In addition, the use of both the notch and the recess in the joint improves the joint strength further. Additionally, in the presented study, experimental data were compared with numerical analysis and it was observed that the data were quite consistent with each other.