Assessment of dynamic response of armor grade steel plates and FMLs under air-blast loads

Abstract

This numerical study represents an effort to characterize the dynamic behavior of distinct armor-grade steel plates and fiber metal laminates (FMLs) of the same masses under blast loads. The blast resistance of finite element models of square steel plates and FMLs is evaluated by applying conventional weapon effects program air-blast loading ranging from 1 to 3 kg of trinitrotoluene (TNT) at a fixed stand-off distance (SoD) of 0.1 m. A user-defined subroutine is used to implement a failure criterion to determine realistic failures in the composite. A variation of kinetic energy, radial deflection, and energy absorptions of the steel plates and FMLs are determined to discover their blast mitigation performance. The deformation modes and equivalent plastic strain of both the steel plate and FMLs are also compared. The obtained results show that the armor-grade AISI 4340 steel has up to 50.5% smaller peak deflection than the other armor-grade steels. The use of FML with multi-thin layers of composite laminate and steel sheets instead of equivalent AISI 4340 steel plate significantly reduces the peak deflection up to 23.9% under similar blast loading conditions. The findings of steel plates and FMLs also represent their applicability for making complex protective structures.