Cyclic fatigue behavior of carbon fiber reinforced vinylester resin composites manufactured by RTM and VARI

The mechanical behavior of [0°]8 unidirectional, [+45°/0°/−45°/90°]S quasi-isotropic and [+45°/−45°]3S angle-ply laminates produced by pressure or vacuum assisted resin infusion from toughened vinylester resin systems with unidirectional carbon fiber fabric reinforcement was investigated. The study included the determination of ultimate in-plane tension, compression and shear properties as well as the characterization of the cyclic fatigue behavior under stepwise increasing and constant amplitude loading. The experimental results showed a better fatigue performance of an epoxy-terminated butadiene-nitrile rubber modified VE resin system. Furthermore, the cyclic strength of the composites produced by VARI was lower compared to RTM composites. From the S–N curves of the quasi-isotropic material for R = +0.1, −1 and +10 the fatigue life diagram was determined.