Design And Fabrication of FML Composites with High Toughness and Impact Strength

Abstract

Fiber Metal Laminates (FMLs) is a hybrid composite material composed of several layers of high strength metal bonded with fiber reinforced composites layers for achieving high strength and light weight material. The aim of the study was to investigate the strength of FMLs composites based on Aluminium alloy 7075 and unidirectional glass fiber sheets bonded with 5052 epoxy having three different stacking sequences, prepared by hand layup method followed by vacuum molding. A series of surface treatments were performed to increase the surface roughness of Aluminium sheet. The resin matrix was modified by the incorporation of 1.5 wt. % nano particles i.e., carbon nanotubes and nano diamonds each. The strength of nano particles based FMLs was compared to that of with bare epoxy adhesives. Tensile and drop weight impact tests were performed on the flat test specimen as per ASTM standards to evaluate the ultimate tensile strength, maximum deformation, and toughness, while the microscopic analysis was conducted to observe the fracture behavior of FMLs. From the results, it was concluded that as the number of Aluminium layers increase with respect to glass fiber, the strength, deformation, and toughness increased. Moreover, inclusion of nanoparticles in resin matrix also showed significant increase in strength than that of bare epoxy adhesives. The Strength of FML as a function of metal volume fraction and nano particle inclusions was evaluated.