Fatigue damage characterization and modeling of a triaxially braided polymer matrix composite at elevated temperatures

A study is conducted to characterize and subsequently model the elevated temperature fatigue behavior of a triaxially braided carbon fiber reinforced polymer matrix composite. An experimental investigation reveals that the elevated temperature environment significantly alters the microscopic fatigue damage evolution and the corresponding stiffness degradation response of the material. The developed fatigue damage model, which is based on quantified parameters of observed damage mechanisms, predicts with a high degree of precision the response of the material for all applied stresses and at both temperatures considered. The predictive model captures the unique characteristics of fatigue damage evolution in the braided composite, and is a viable design tool. Overall, this study yielded a fundamental understanding of microscopic fatigue damage evolution and local deformation behavior of the braided composite.