Numerical and experimental investigation of hybrid adhesive joint failure

In this dissertation, the effect of hybrid bonding pattern on failure load and stress distribution along single lap joint bondline was mainly investigated. In the present dissertation, primarily, the analytic model of hybrid adhesive joint was formed. After this stage, the analytic model was validated by comparing the two and three-dimension linear finite element analysis as a result of modifying the length rates of adhesives in hybrid bonding pattern. In the experimental part of the dissertation, mono and hybrid adhesive joints were compared by determining failure loads and behavior. In the experiments, apart from the adhesives used to validate the analytic model, three adhesives with different characteristics were selected in order to be used in both joint types. The adhesives used were identified as stiff, tough, and flexible adhesives based on their characteristics. In the middle of the bondline length, stiff adhesive was used and at the edges flexible and tough adhesives were used respectively. In the final stage of the dissertation, non-linear finite element analyses were carried out for mono and hybrid adhesive joints by implementing exponential Drucker Prager material model. Depending on the results of the analysis, failure loads were compared with experimental failure loads and stress distributions were presented along with the adhesive bondline. As a result, when length ratios are selected properly and appropriate adhesives are used along the overlap length edge, the strength of hybrid adhesive joint, when compared to mono adhesive joint, was found to increase considerably.