TOTAL FATIGUE LIFE MODEL FOR T700 CARBON/VINYL ESTER COMPOSITES-MODE I LOADING

摘要

Total fatigue life methodology proposed previously was applied to T700 carbon/vinyl ester composite laminate for marine applications. T700 carbon fiber has high fracture strain and strength and intermediate modulus. Multilayer and multiaxial fibers knitted by polyester fibers are available as stitch bonded fabric. Mode-I fracture test was conducted to obtain the fracture resistance G{sub}(IR) as a function of delamination extension. Fatigue onset life test was conducted to determine the threshold energy release rate, G{sub}(Ith). The fracture resistance equation was G{sub}(IR)=0.175+0.56(a-a{sub}0){sup}0.39 and G{sub}(Ith)=0.18G{sub}(IC), where G{sub}(IC)=0.175kJ/mm{sup}2. Constant amplitude cyclic opening displacement fatigue test was conducted to establish the delamination growth rate da/dN as a function of maximum cyclic energy release rate G{sub}(Imax)/G{sub}(IR).