Characterization of Splitting Growth Behavior in Unidirectional Carbon Fiber Reinforced Plastic Laminates with a Notch Subjected to Fatigue Load

Abstract

Tensile fatigue tests using acoustic emission (AE) measurements were performed on unidirectional carbon fiber reinforced plastic (CFRP) laminates with a notch to investigate the relationship between the fatigue damage behavior and the associated AE behavior. Immediately subsequent to the initiation of the tests, splitting occurred along the direction of the fiber from the tip of a notch, and rapidly progressed for all investigated stress levels. Thereafter, the rate of development was almost constant after 3×10⁴ cycles and the AE behavior also changed. These results indicate that the AE behavior is indicative of the splitting behavior. We discussed the AE behavior based on the experimental results for the splitting behavior and the relationship between the AE, and the fatigue damage behavior of the unidirectional CFRP laminate was obtained. From this relationship, it is possible to predict the damage type, size, and quantity by comprehensively evaluating the frequency characteristics, and each parameter of the AE waves.