On temperature-dependent fiber bridging in mode I delamination of unidirectional composite laminates

This paper aims to investigate the temperature dependency of fiber bridging in mode I delamination of unidirectional laminates. Double cantilever beam tests under temperatures ranging from − 20 °C to 110 °C were conducted to determine the effect of temperature on the resistance curves and bridging tractions, and denser bridging fiber and higher bridging traction were observed with increasing temperature. Scanning electron microscope fractography revealed more ductile matrix fracture at higher temperatures indicating a transition in the failure mechanism. A modified trilinear cohesive zone model was developed by considering the temperature effects on fracture toughness (initial and steady) and bridging traction. The model was successfully implemented in finite element software and provided excellent predictions of experimental load–displacement response. Both the experimental and numerical results showed a decrease in crack propagation speed at higher temperatures, which was attributed to enhanced matrix ductility and fiber bridging densification.