Modeling of fatigue damage in a polymer matrix composite

In recent years, advanced polymer matrix composites (PMC) are increasingly used in high-speed transport airframe structures and aircraft engine components due to their light weight, high strength, and high stiffness properties. One critical issue for structural designers and material developers is the long term behavior of these PMC and their associated damage and failure mechanisms under fatigue loading. In this study, fatigue damage of a polymer matrix composite proposed for high temperature applications was characterized both at room and high temperatures. The objective of this research is to predict the damage development under specific load and temperature. A Monte Carlo technique was applied to simulate the nondeterministic transverse cracking based on the stress-life curves, a simple damage accumulation model and stress analysis model. The probability density function of transverse crack spacing was obtained and a theoretical model was proposed to predict this damage development in terms of crack densities versus number of cycles. It is shown that both the simulation and the theoretical model agree well with experimental results at various load levels and temperatures.