Investigation of Multi layered Mitigation Systems for Protection from 120mm Mortar HE Top Attacks

Abstract

This paper investigates the protection of reinforced concrete (RC) structures from the Mortar 120mm HE (high explosive) top attacks. Two multi-layered mitigation systems are proposed to be added on RC structures' roofs to achieve full protection against the Mortar 120mm destroying effects (i.e. ballistic penetration and explosion effects). The proposed mitigation systems combine relatively high-strength materials, to stop or slow down the projectile, with lightweight porous materials, to attenuate the explosion shock wave. Another function of the porous materials is to increase the thickness of the proposed mitigation systems and hence increasing the explosion stand-off distance. Traditional construction materials, steel and RC, were used as cheap high-strength materials, whereas commercial rigid polyurethane foam and light-weight brick were examined as shock wave absorbers. Two firing tests of the 120mm bomb from cannon barrels against one-story RC structures strengthened with the proposed protection systems were executed. A numerical simulation of the real firing tests was performed via Autodyn hydrocode to further analyze the performance of the constituting components in alleviating the round effects. The current study demonstrated that the proposed mitigation systems, which are based on the multi-layering concept, are efficient and have their merits in defeating the Mortar 120mm HE attacks.