Effects of sand filling on the dynamic response of corrugated core sandwich beams under foam projectile impact

How sand filling affects the dynamic response of metallic corrugated sandwich beams under shock loading was characterized, both experimentally and numerically, with shock loading simulated by high-speed impact of aluminum foam projectiles at beam mid-span. To facilitate evaluating the effects of sand filling, both empty and sand-filled corrugated core sandwich beams were assessed and compared for shock resistance. Representative deformation processes, deformation and failure modes, and beam deflections were experimentally obtained and analyzed. Sand-filled sandwich beams exhibited much higher shock resistance than the empty ones. Numerical simulations were subsequently conducted using a coupled discrete particle/finite element approach that takes into account the coupling interaction between the sand grains and corrugation members. The simulations predicted reasonably well the primary features (permanent mid-span deflections and deformation modes) of both the empty and sand-filled sandwich beams observed experimentally. The validated numerical model was employed to evaluate how the properties of the filling sand and other granular filling materials, e.g., density, stiffness, friction and damping, affect the shock resistance of sandwich beams. The results indicated that the shock resistance was sensitive to, firstly, the density and stiffness of sand and, secondly, the friction between sand particles. In contrast, the damping between sand particles had little effect.