10 - The fatigue behavior of composite materials for high-temperature applications

Abstract

This chapter introduces fatigue behavior of lightweight composite structures, which include the polymer matrix composites, especially the high-performance thermoplastics (polyphenylene sulfide (PPS) and polyether ether ketone (PEEK)), as alternative materials for thermosetting polymer composites (epoxy and polyester matrix). Fatigue is affected by various parameters including mechanical, microstructural, and environmental (ultraviolet, temperature, moisture, and radiation). There are mutual effects between the environment and the microstructure of polymers and their composites, especially for thermoplastic composite types. Fatigue leads to the collapse of most mechanical properties beyond the glass transition temperature, which is often reflected in the fatigue behavior. The chapter starts by presenting the basic concepts of fatigue failure and the important models that deal with fatigue modes. It then explains the principles of damage in polymer composite materials and the mechanisms of preventing fatigue failure in polymers and polymer composites. At the end of the chapter the stress–number cycle curves of PPS and PEEK are compared with those of other polymer composites at room temperature and above.