An experimental and numerical study on adhesive joints for composites

In many composites structures the use of joints allows not only more versatility during the assemblage process but also reduces the cost during the manufacturing. As joints are considered regions of weakness, their study has been conducted since late 1930s. Researchers have been working on new joint designs looking for better performances. One of these new designs is the bonded wavy-lap joint presented by Zeng and Sun in 2001. This paper addresses the advantages and disadvantages of the wavy-lap joint and a modified wavy-lap joint design is studied. To be able to guarantee the data consistency a statistical study is performed considering not only the sample size population but also the statistical differences between the single-lap and wavy-lap joints. Besides, the experimental tests, a finite element simulation is carried out to analyze the stress fields inside the joints. The results show an average increase on loading to failure close to 41%. This fact could be due to the compressive stress field developed inside the wavy-lap joint. In addition, this stress field distribution can also be the reason for the adherent delamination observed on the wavy-lap joints. So far, the modified wavy-lap joint seems to lead to stronger joints.