Fracture and Fatigue Behavior of Polymer Nanocomposites—A Review

Abstract

Fiber reinforced polymer (FRP) composites are widely used in structural applications, mainly due to their high specific strength and stiffness. These composites experience several types of static and fatigue loads in service. For a safe and durable structure, high fracture toughness and enhanced fatigue life are prominent requirements of these composite materials. Efforts have been made in recent times to improve the fracture toughness and fatigue properties of FRP composites by incorporation of second phase fillers in the epoxy matrix. Addition of nano sized fillers to the epoxy has led to the development of a new class of materials—polymer nanocomposites. The presence of nano fillers has been shown to improve the fracture toughness and fatigue life of bulk epoxies as well as FRPs with nano-modified epoxy matrix. The type of nano filler, its shape, size, volume fraction and dispersion in the epoxy have all been shown to influence these properties significantly. In this review, an overview on the effect of nano fillers on the fracture toughness and fatigue life of bulk epoxies and FRPs is presented. The mechanisms proposed for observed improvements in these properties and the empirical method of prediction of fatigue life of nanocomposites subjected to spectrum fatigue loads simulating service loads are also discussed.