A review of methods for improving interlaminar interfaces and fracture toughness of laminated composites

Abstract

Interlaminar fracture or delamination is one of the major failure modes for fiber reinforced polymer (FRP) and fiber metal laminate (FML) composites. Many studies have been carried out to investigate the mechanisms affecting this interlaminar failure and ways to improve the interlaminar fracture toughness (ILFT) of FRP composites and FMLs. However, information on the topic is scattered, with studies having different emphases. Therefore, in this review, the studies are surveyed and put into perspective in terms of the improvements to ILFT achieved. A wide range of methods to improve the ILFT of FRP composites and FMLs is presented. For FRP composites, the methods include modifications to the constituents or interlaminar regions of the composite, applications of nano-fillers in multiscale composites approaches, and through thickness reinforcement techniques. For FMLs, studies on various surface treatment methods for the metal in FMLs are included. The strengthening mechanisms involved in each of the methods are also discussed. This review provides a comprehensive picture of the different methods to improve interlaminar interfaces in laminated composites, including their performances and drawbacks, as well as the future trends in the related topics.