Numerical simulation of pin-loaded joints of fiber metal laminate

Fiber metal laminate (FML) is an advanced composite material, which consists of metal layers and polymer matrix composites. Due to the combination of the advantages of traditional metal and composite materials, FML has been widely used in the aircraft industry. Due to advantages in inspection and reliability, the mechanically fastened (riveted or bolted) joints are essential for a complex structure. The present study investigated the effects of geometry parameters and ply stacking sequences on the mechanical properties of pin-loaded FML joints. A three-dimensional progressive failure model had been created to investigate the failure response of FML joints. A comparison between simulation and experimental results showed a good agreement on the strength and internal damage pattern (fiber damage, matrix damage, and cohesive layer delamination between 0° fiber and outer aluminum) for the pin-loaded FML joints. It was found that ultimate failure strength increased with the increase of width-to-diameter ratio (W/D) or edge distance-to-diameter ratio (E/D). The failure modes of pin-loaded FML joints were dissimilar by varying the ratios of W/D and E/D. The dominant failure mode of studied joints was bearing failure mode. Numerical simulation results showed that ply stacking sequence has obvious effects on the mechanical properties of FML joints.