Effect of adherends misalignment angle on bending strength of an adhesive joint: numerical and experimental results

Bonded joints allow reducing the product weight and increasing fatigue resistance as compared to mechanical ones. Single-lap bonded joint (SLJ) is a simple example of this kind of joint. Literature focuses its attention on increasing the strength of SLJs; however, they do not consider the geometric deviations of the manufacturing process and used equipment, such as the adherends’ misalignment. This work presents a 3D numerical model that puts into relationship the adherends’ misalignment and the strength of a joint subjected to a 3-point bending test. The misalignment between the adherends was considered as the rotation of an adherend with respect to the other around two different axes. The 3D numerical model was also experimentally validated. To carry out the experimental tests, new equipment to accurately bond the adherends with a known value of misalignment between the adherends was designed, manufactured, and used. The experimental results are very similar to those obtained numerically by testifying a good agreement. The results show that the misalignment between the adherends decreases the bending strength the more the misalignment angle increases. The reduction ranges from 2% to 12% with the increase of the misalignment angle around an axis parallel or perpendicular to that of the adherends, respectively.