Influence of matrix toughness and ductility on the compression-after-impact behavior of woven-ply thermoplastic- and thermosetting-composites: A comparative study

This study was aimed at comparing the residual compressive strength and behavior of TS-based (epoxy) and TP-based (PPS or PEEK) laminates initially subjected to low velocity impacts. Provided that the impact energy is not too low, the permanent indentation is instrumental in initiating laminates local buckling under compressive loadings. CAI tests revealed that matrix toughness is not the primary parameter ruling the damage tolerance of the studied materials. However, matrix ductility seems to slow down the propagation of transverse cracks during compression thanks to plastic micro-buckling which preferentially takes place at the crimps in woven-ply laminates. It could therefore justify why the matrix toughness of TP-based laminates does not result in significantly higher CAI residual strengths. Finally, the compressive failure mechanisms of impacted laminates are discussed depending on matrix nature, with a particular attention paid to the damage scenario (buckling and propagation of 0° fibers failure).