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Empirical model for predicting fatigue damage behavior of composite materials developed recently has been applied to composite materials made of different fibers in various configurations: carbon and glass fiber noncrimp fabric reinforced epoxy composites, chopped strand mat glass fiber-reinforced polyester composites, randomly oriented nonwoven hemp fiber-reinforced polyester composites, and glass/hemp fiber-reinforced polyester hybrid composites. The fatigue properties were evaluated in tension–tension mode at stress ratio R = 0.1 and frequency of 1 Hz. The experimental fatigue data were used to determine the material parameters required for the model. It has been found that the model accurately predicts the degradation of fatigue life of composites with an increase in number of fatigue cycles. The scope of applicability of this model has thus been broadened by using the fatigue data of natural fiber and noncrimp fabric composites.

Experimental studies have been conducted to evaluate static tensile and tension–tension fatigue response of unidirectional glass fiber non-crimp fabric composites subject to seven different stabilization patterns (two multiaxial and five uniaxial stabilizing yarns). The effect of stabilization patterns on non-crimp fabric is crucial as they produce different mesoscale bundle shapes and bundle volume fractions which may affect the static and fatigue properties of non-crimp fabric composites. The studies show that tensile modulus and fatigue life decline with increasing amount of uniaxial stabilizations. Different stabilizations with different bundle shapes influence the final composite properties through various factors than just the volume fraction. The multiaxial stabilizations with higher static tensile strength have shorter fatigue life as compared to uniaxial stabilizations with lower tensile strength. As the areal weight of stabilizing yarns increases, fatigue life decreases at all stress levels which show the deleterious effects of stabilizations on the fatigue behavior of composites. Areal weight and orientation of stabilizing yarns should be optimally selected for the anticipated performance of the non-crimp fabric composites.