Enhancement in fatigue performance of FRP composites with various fillers: A review

Engineering structures are often subjected to fluctuating loads, which onset materials' fatigue and deleteriously affect their service life. This becomes crucial for fiber reinforced polymer (FRP) composite structures because their fatigue response is different from metals, complex, and can lead to catastrophic consequences. The desire and need to improve fatigue performance have been progressive and have led to the use of fillers as secondary reinforcement in matrix. In fact, ceramic, carbonaceous, clay, and polymer fillers have been extensively studied to enhance mechanical performance, but very limited study is available on the fatigue performance of FRP composites modified with fillers. Therefore, this work includes an extensive review on the use of fillers reinforcement to improve the fatigue performance of FRP composites, especially with thermoset and thermoplastic matrices. The various fatigue improvement mechanisms contributed by fillers are identified and explained. A comparison is made among the available literature to map the enhancement in the fatigue life of carbon and glass reinforced composites and the filler content used therein. This review shows that carbonaceous and polymer fillers have a positive reinforcing effect and provide maximum improvement in fatigue life by a factor of 11 and 100, respectively. There is enough evidence that the addition of fillers enhances the fatigue strength of thermosets composites, whereas not enough data is available yet to understand the fatigue performance of thermoplastic composites with fillers in entirety. In the end, the future potential and the likely challenges are summarized and discussed.