Local evaluation of adhesive failure in similar and dissimilar single-lap joints

Abstract

Single-lap joints made of aluminium and carbon fibre adherends are tested to understand better the behaviour of such dissimilar joints. Local deformation fields are monitored by using the digital image correlation method (DIC). Over the overlap length strain gauges are emulated as to measure properly the strains in the adhesive. Peeling and shearing strains are investigated, emphasizing that peeling is important in the region where failure is initiated, towards the extremity of the overlap region. Cohesive Zone Modelling (CZM) available in Abaqus® was used to simulate the behaviour and strength of dissimilar single-lap adhesively bonded joints. A linear elastic FEM was used. A distinct CZM model is used to show the variation of normalized stresses and damage in the process zone of the single-lap joint. Experiments show that the use of dissimilar aluminium-carbon and carbon-carbon adherends is reducing the strength and stiffness of the joints as the delamination and pull-out of the carbon fibres compromises their integrity. Numerical simulations overestimate the experimental strength and stiffness of the joints. FEM model has to be improved as to consider a refined laminate modelling.