Study of debond fracture toughness of sandwich composites with nanophased core

Debonding of the core from face sheets is one of the major failure modes in a sandwich structure. This paper investigates the effect produced by the addition of nanoparticles to the foam core on the debond fracture behavior of sandwich composites. Polyurethane foam core is modified with different types of nanoparticles, namely nano TiO2, nanoclay, carbon nanofibers (CNFs), and multi-walled carbon nanotubes (MWNTs), keeping the face sheet unaltered. The loadings of nanoparticles are increased in a step of 0.5% by weight to attain optimum properties enhancement. The modified foam core along with S2-glass/SC-15 epoxy is used to manufacture sandwich composites using a co-injection resin infusion molding (CIRIM) technique. Specimens are tested in mode-I under “Tilted Sandwich Debond” (TSD) configuration. It is observed that sandwich composites with nanophased core at 1 wt.% loading of nanoclay show the highest enhancement in debond fracture toughness (about 69%) as compared to neat foam core. Among different sized nano TiO2, 5 nm one shows the highest improvement of about 50%.