- The damage and fracture behavior of Fiber Reinforced Polymers (FRPs) is quite complex and is different than the failure behavior of the traditionally employed metals. There are various types of failure mechanisms that can develop during the service life of composite structures. Each of these mechanisms can initiate and propagate independently. However, in practice, they act synergistically and appear simultaneously. The difficulties that engineers face to understand and predict how these different failure mechanisms result in a structural failure enforce them to use high design safety factors and also increases the number of certification tests needed.