Date of this Version
Mechanical properties of composite materials made of high modulus fibers and relatively low modulus polymeric matrix, such as graphite/epoxy laminated composites, are sensitive to loading rate and temperature. Generally, at fixed loading rate, when temperature increases, the fracture toughness of polymers also increases; however, it will decrease with the increase of loading rate at constant testing temperature. Rate effects on fracture toughness are of critical to understand the fracture transition from ductile to brittle of some polymers. However, there have been fewer studies of rate effects on delamination toughness of laminates compared to that of pure polymers. In the present work, the double-cantilever beam (DCB) test geometry is utilized for studying the effects of loading rate and testing temperature on mode-I delamination toughness of a graphite/epoxy laminate made of commercial thermal-setting prepreg, Hexcel T2G190/F263. The thermal activation model of fracture is suggested for data reduction.