Experimental Study on Rotating Bending Fatigue Behavior of Carbon Fiber Reinforced with Epoxy Composites Using Statistical Analysis.

In this study, rotating bending fatigue tests have been conducted for carbon fiber-reinforced epoxy composites. Hollow cylindrical specimens were prepared for two different lay-up sequences, i.e., [± 45°]₂ and [± 45°/(90°)₂] using filament winding process. These specimens were tested at constant stress levels with zero mean stress using an in-house built rotating bending fatigue testing machine. Several failure modes including matrix cracking, fiber pull-out, and longitudinal splitting of fibers from the matrix and fiber failure have been ascertained using a scanning electron microscope. The probability distribution of fatigue life results of the test specimens is statistically analyzed using the two-parameter Weibull distribution function. Higher shape parameters are witnessed for both the stacking sequences at lower stress levels, indicating less dispersion in the fatigue life during high cycle fatigue. S–N diagrams are drawn for the different probability of failures (P_f = 0.10, P_f = 0.37, P_f = 0.50, and P_f = 0.99) for the benefit of machine designers to identify the first failure time. [ABSTRACT FROM AUTHOR]