Strength and energetic optimization of dual-adhesive T-joints

Adhesive joints are widely used today in industrial sectors. Currently, modelling techniques such as cohesive zone models (CZM) have already demonstrated that it is possible to accurately predict the strength of adhesive joints. However, the harmful effect of peel stress concentrations in adhesive joints should be considered. Aiming to improve the strength of adhesive T-joints, in this work dual-adhesive joints (DAJ) are studied. This technique consists of using two adhesives, placing a more ductile adhesive at the overlap ends and a brittle one in the central area. To test this method in T-joints, various combinations of adhesives are evaluated. Various relative lengths between adhesives along the bondline are tested, always keeping joint symmetry. To evaluate these combinations, a CZM study was carried out. It was initially possible to validate the CZM technique with experimental results. The numerical work that followed showed that the strength of T-joints significantly depends on the combination of adhesives used, and that it is possible to achieve significant increases in strength and dissipated energy relative to single-adhesive joints (SAJ).