Experimental studies of CFRP laminates under repetitive low-velocity impact loading

Abstract

Due to their exceptional properties such as high strength-to-weight ratio and fatigue tolerance, laminated composites are widely used in aircraft structures. When subjected to impact loading, composite structures experience intra/inter-laminar damages, and it is crucial to investigate the effect of damages on the strength of the laminate. Single and multiple impact tests are performed on CFRP laminates with different stacking sequences. Cross-ply [0/90]4S and quasi-isotropic [45/90/-45/0]2S laminates are fabricated and tested. Damage size as a function of the number of impacts and impact energy for different stacking sequences are studied. The damage configuration of impacted specimens is studied using the immersion ultrasonic technique. Damage size and shape of multiple impacted specimens are compared with single impacted specimens.