Experimental Investigation of Foam-Filled Composite Double-Arrow Auxetic Structures in Impulse Loadings

composite double-arrow auxetic structure was fabricated by using the hot mold pressing and bonding technologies, and a polyurethane foam was utilized to fill the voids of core to prepare a foam-reinforced auxetic structure. Projectile impact experiments were carried out to investigate the influence of the filling foam on the dynamic response, the failure mechanism and a negative Poisson’s ratio on the composite double-arrow auxetic structure. A high-speed recording system was used to gather data on the deformation profile and failure mechanism of the composite auxetic structure during the impact loading. The foams were found to significantly reduce the local crushing and overall bending/shear deformation of the sandwich structure. This synergistic effect of the core member and foam blocks greatly enhanced the impact resistant and energy absorption capacity of the composite auxetic structure. However, filling foam would reduce the negative Poisson’s ratio effect of the auxetic structure.