Fusion bonding of thermosets composite structures with thermoplastic binder co-cure and prepreg interlayer in electrical resistance welding

A new concept combining both thermoplastic binder co-cure and prepreg interlayer is proposed and investigated for fusion bonding of thermosets composite structures. Three different thermoplastic binders were co-cured respectively onto the surface of the carbon fiber reinforced epoxy (CE, Epoxy) composite laminates to form an auxiliary medium for electrical resistance welding. The carbon fiber reinforced binder (CF/Binder) prepreg interlayer, which is compression molded with a single layer of carbon fiber fabric sandwiched between two binder films, was designed as the heating element. Double cantilever beam (DCB) specimens were fabricated by fusion bonding of the CE, Epoxy composite laminates. The influence of the thermoplastic binders and the CF/Binder prepreg interlayers on the mode I interlaminar fracture toughness (GO and the morphology of the fracture surface were studied respectively by double cantilever beam test and scanning electron microscope. The results indicate that a maximum average delamination strength CRT of 1879.6 J/m(2) was obtained in the case of the AXS900 binder welded specimens using twill weave fabric head lig element. Three types of failure pattern can be visually and microscopically observed, i.e. interfacial-type failure, cohesive-type failure and interlaminar-type failure. (C) 2016 Elsevier Ltd. All rights reserved.