A study on the failure behavior and mechanical properties of unidirectional fiber reinforced thermosetting and thermoplastic composites

Failure behavior and mechanical properties of unidirectional (UD) carbon fiber reinforced polyamide 6 (CF/PA6) and epoxy resin (CF/Epoxy) laminates were investigated through tensile tests in this study. The fracture modes of both CF/PA6 and CF/Epoxy were discussed based on the fiber orientation, interfacial properties, Mode II interlaminar fracture toughness and the brush width. Meanwhile, Global load sharing (GLS) model was employed to compare with the experimental mechanical properties and corresponding fracture mechanics model was employed to analyze the fracture behavior. The results showed that UD CF/PA6 laminates with weak interface but high Mode II interlaminalr fracture toughness mainly exhibited step-like fracture modes (77%) in interfacial fracture mode (Adhesive failure), while CF/Epoxy laminates with stronger interface but lower Mode II interlaminalr fracture toughness mostly showed splitting fracture mode (69%) in matrix fracture mode (Cohesive failure).