R. Sheley, S. Khaleghi, J. Tate, M. Tehrani
Texas State University,
United States
Keywords: high temperature thermoplastic composites, tension-tension fatigue, damage mechanism, carbon fiber reinforced LM-PAEK composites, automated fiber placement
Summary:
Low-melt polyaryletherketone (LM-PAEK) has emerged as a high-temperature thermoplastic matrix of significant relevance in aerospace, automotive, marine, and energy sectors due to its high specific strength, chemical resistance, and thermal stability. The continuous demand for lightweight structures that can sustain cyclic mechanical loading in extreme environments necessitates a detailed understanding of the fatigue performance of LM-PAEK-based composites to ensure long-term reliability and safety. In this study, carbon fiber reinforced LM-PAEK laminates were fabricated using automated fiber placement (AFP) followed by vacuum bag oven (VBO) consolidation to achieve uniform fiber distribution and low void content. The fatigue response under load-controlled tension-tension conditions at 5 Hz was systematically investigated to quantify stiffness retention and fatigue life. The experimental analysis was complemented by a statistical evaluation of life expectancy to establish reproducibility and processing–performance correlation. The results indicate that LM-PAEK composites maintain excellent fatigue resistance, minimal stiffness degradation, and consistent structural integrity under cyclic loading. The optimized AFP–VBO processing parameters played a crucial role in enhancing interlaminar bonding and delaying fatigue onset. These findings demonstrate that LM-PAEK-based thermoplastic composites are promising candidates for the next generation of high-performance, thermally stable, and fatigue-resistant components in aerospace and energy systems.