Research On The Penetration Behavior Of Sandwich Protective Structures With Aluminum Foam Cores Under Impact Loading

Aluminum foam sandwich plate structures have many good characteristics,for example, light quality, high specific stiffness and good performance of shockwave scattering, and so on. They have wide applications in the high-tech domain,such as aerospace, military vehicle, shipbuilding, nuclear industry, and so on. Aslight composite armor, aluminum foam sandwich structures are inevitablysubject to the impact of bullet, detonation products or debris. Therefore, it isnecessary to investigate the anti-penetration performances of aluminum foamsandwich plates. In order to discuss their anti-penetration performance,experimental investigation, theoretical analysis and numerical simulation arecarried on the dynamic responses of aluminum foam sandwich plates impact bydifferent nosed projectiles in this paper. Some significant conclusions are drawn.The experiment research of penetration of aluminum foam sandwich platesby different nosed projectiles is carried. The deformation and failure modes ofsandwich plate are given, and the influences of different nosed projectiles, the core thickness and face sheet thickness on the penetration effect are investigated.The results show that the damage and deformation occur only in those regionsdirectly beneath the projectile, and do not spread laterally; the anti-penetrationperformance of sandwich plate can be improved by increasing the face sheet orcore thicknesses, it is the best for flat-ended projectile, and it is the most weakfor cone-nosed projectile.In this paper, the multi-stage analytical models are developed to investigatethe penetration and perforation of aluminium foam sandwich plates by differentnosed projectiles. The analytical solutions of resistance and instantaneousvelocity of penetration are produced. The effects of the sizes, the core densityand initial velocity of projectile on absorbed energy are analyzed. Numericalsimulation of aluminum foam sandwich plates of different sizes and face-sheetcombination under steel projectiles impact is carried out using finite elementcode LS-DYNA. The processes of deformation and damage are investigated.The effects of relevant parameters on the anti-penetration performance andabsorbed energy are also discussed. Results show that anti-penetrationperformance of sandwich plate enhances with the increase of core density andthickness. The energy absorption of sandwich plate also increases with theincrease of initial velocity and diameter of the projectile. The anti-penetrationand energy absorption performance not only depend on strength of panelmaterials, but also on the sequence of panels.Numerical simulations of the anti-penetration performance of multi-layered targets have been also undertaken using finite element code. The effects ofdifferent number, thickness, arrangement and layout are analyzed. The bestballistic performance of double-layered target is achieved when the ratiot1t1t2is about0.25, and the worse performance occurs when the ratiois0.5. As for triple-layered targets, the ballistic performance increaseswith the decrease of the thickness of the first layer.