Effects of Geometrical and Material Features on Damage Onset and Propagation in Single-lap Bolted Composite Joints under Tensile Load: Part II – Numerical Studies

A numerical investigation has been carried out in single-lap bolted composite joints. A previously developed three-dimensional progressive damage FEM model, based on the Hashin failure criteria and ply discount material degradation rules, has been adopted in order to point out the influence of geometrical and material characteristics on the damage onset and propagation under tensile loading conditions. The numerical results in terms of load versus displacement curves and in terms of strains have been compared with experimental data presented in Part 1 of the present study. From the same experimental campaign, useful data on damage evolution, found by non-destructive ultrasonic evaluations, have been used to further validate the adopted numerical tool. This tool has been found to be able to give detailed information, complementary to the experimental data, on the matrix cracking and fiber breakage onset and growth during the loading process in composite single-lap joints with different bolt types (protruding and countersunk), different bolt diameters, and different plates' interfaces (composite-composite and composite-aluminum).