Adhesively bonded joints with non-flat interfaces

• Online Access: http://hdl.handle.net/2047/d20001054

Adhesive bonding is used in many structural applications such as aircraft and aerospace industries due to its low-weight and fatigue-resistance and capability to attach dissimilar materials. One shortcoming of using adhesively bonded joints is that in most cases the bonded joint is the `weakest link' of the structure and has inferior strength compared to other components, thus, limiting the overall load carrying capacity of the structural system. In this study, we examined the strength, energy absorption and failure of bonded joints with non-flat interfaces. Single lap bonded joints with different zig-zag shaped (dented) interfaces were fabricated and their response under uniaxial tension was compared with the response of a single lap joint with traditional flat interface. In the experiments, the yield stress, ultimate tensile stress, maximum elongation and energy absorption were obtained and compared in the different types of bonded joint. It was shown that these structural properties vary greatly by changing the topology of the adhesive-adherent interface, promising unique potential applications for each of the configurations studied. In the next step, we carried out a parametric finite element study to investigate the role of several geometrical parameters such as dent height, width, angle and also the adhesive Young's modulus on the distribution of pealing and shearing stresses in the bonded joints. The results were linked to the experimental observations. Also in this study, the crack shielding phenomena in the different types of joints was studied using finite element calculations and related to qualitative experimental observations.