Abstract: The penetration behavior of metallic sandwich plates with honeycomb core under low-velocity impact was experimentally studied with the DHR testing system. Impact force-displacement responses of sandwiches with different core thickness under blunt, spherical, conical projectiles impacting were demonstrated. The effects of the core thickness and projectile’s shapes on final fracture modes, impact force-displacement responses and critical fracture energy of sandwiches were analyzed. Experimental results showed that “shear fracture mode”, “tensile fracture mode” and “diamondoid fracture mode” were found on the top face-sheets of sandwich plates when the shapes of the projectiles are blunt, spherical and conical respectively. “Shear fracture mode”, “petaloid fracture mode” and “petaloid fracture mode” were found on the bottom face-sheets of sandwich plates when the shapes of the projectiles are blunt, spherical and conical respectively. “Single peak modes” were found in the impact force-displacement responses during the spherical and conical projectile loading on the thin sandwich plates, while “double peaks modes” occurred when the sandwich plates were thick. Both the thin and thick sandwich plates under blunt projectile impact, the impact force-displacement responses accorded with “double peaks modes”. The ability against perforation of the thin sandwich plates appeared to be the best under spherical projectiles impacting, while the worst under blunt projectiles impacting. The ability against perforation of the thick sandwich plates appeared to be the best under conical projectiles impacting, while poorer under blunt and spherical projectiles impacting.

Key words: Metallic honeycomb, Sandwich plate, Penetration, Low-velocity impact, Experimental investigation