R. Sheley, J.S. Tate, M. Tehrani
Texas State University,
United States
Keywords: high temperature thermoplastic composites, tension-tension fatigue, damage mechanism
Summary:
High-temperature thermoplastic composites (HTTPs), such as carbon fiber-reinforced polyether ether ketone (PEEK) and polyether ketone ketone (PEKK), low modulus poly aryl ether ketone (LM-PAEK), are increasingly utilized in industries like aerospace, marine, automobile and energy. These materials provide superior mechanical properties, chemical resistance and thermal stability. As technology advances, the use of HTTPs is expected to continue growing, revolutionizing the way industries design and manufacture their products. In the application, these materials are often exposed to cyclic loading conditions in extreme environments, leading to potential failure if not properly monitored and maintained. Hence it is necessary to understand the endurance limit of these materials to ensure their safe and reliable performance. This study investigates the fatigue and fatigue damage mechanisms in high-temperature thermoplastic composites. The primary objective is to evaluate the tension-tension fatigue behavior and identify key damage causes using Scanning Electron Microscopy (SEM). For this research samples of LM-PAEK were prepared through compression molding and vacuum bagging techniques, ensuring consistent material quality. Fatigue tests under cyclic loading were conducted to assess the composites' durability, while SEM analysis provided detailed insight into the morphology and microstructural changes, revealing failure mechanisms such as matrix cracking, delamination, and fiber-matrix debonding. Key results demonstrated that processing methods and load frequency influence fatigue life. The study concludes that LM-PAEK composites, with careful processing, show promising fatigue resistance, making them suitable for high-performance applications in the aerospace and automotive industries. These findings provide a framework for optimizing composite design and enhancing material reliability under cyclic loading conditions.