Influence of damage onset and propagation on the tensile structural behavior of protruding composite joints

Abstract. In the present paper, a detailed numerical investigation of the structural behaviour of single-lap protruding composite joints under tensile loading has been carried out using a three-dimensional progressive damage FEM model. The adopted FEM model is based on a combination of Hashin’s failure Criteria, ply-discount material’s degradation rules and penalty method (for contact-friction phenomena). Some joints ’ configurations with different hole’s diameter and different interfaces (composite/composite and composite/aluminium) have been analysed. The numerical results in terms of strain curves, load-displacement curves and damage propagation have been compared with experimental data in order to point out the effectiveness and the weak points of the proposed progressive damage approach. Comparisons between the numerical damage and no-damage approach for each configuration have been carried out in order to analyse the influence of progressive damage approach on the numerical simulation of the overall structural behaviour. Also the influence of penalty contact stiffness on the damage onset and damage propagation inside the joints has been investigated. Finally, particular emphasis has been given to the damage onset and damage propagation inside the joints critically discussing the differences among the analysed geometrical configurations