Influence of adherend geometry modifications on the shear performance of single lap adhesive joints

Abstract

In this study, the effects of various pocket designs on single lap adhesive joints with PMMA adherends were systematically investigated. A finite element method (FEM) analysis of the unmodified joint was first performed to identify critical stress concentrations within the adhesive layer, and the pocket geometries were subsequently developed based on the resulting stress distributions. The pocket configurations were also designed to reduce adhesive consumption without compromising mechanical performance, while considering sustainability aspects. The geometric characteristics of the machined pockets were verified by optical microscopy. Single lap shear tests were carried out in accordance with ASTM D1002, and the experimental data were statistically analyzed using Analysis of Variance (ANOVA) to determine the parameters with the most significant influence on joint performance. A maximum shear load of 618.67 N was obtained for the joint incorporating six horizontally aligned blind pockets, corresponding to a 75% improvement compared to the unmodified joint. Furthermore, ANOVA results indicated that the number of blind pockets was a dominant factor affecting joint performance.