Numerical Investigation on Blast Response of Cold-Formed Steel Framing Protected with Functionally Graded Composite Material

This paper presents a numerical simulation on the blast response of cold-formed steel (CFS) structural framing system protected with a functionally graded composite material (FGM) panel. The steel frame consists of four CFS studs, which were protected by 12.5 mm thick gypsum, aluminum composite, and FGM composite materials on both sides. The numerical simulation was performed using ABAQUS on a 1.8 m x 2.4 m, overall wall panel exposed to air blast on one side. A 1.0 kg TNT explosive charge placed at four standoff distances (R) of 1.0 m, 1.5 m, 2.0 m, and 2.5 m from the framing were investigated. The FGM board was modeled using a stepwise material variation using the power-law material function. Deformation and failure modes of the studs, as well as the protective materials, were compared to the same framing system but with different protective materials, including conventional gypsum boards and aluminum composite panels. Based on the observation from the analysis and computational simulation, the proposed protective composite material (FGM) resulted in a smaller deformation at peak overpressure at a given standoff distance (R) and local failure modes on studs. The same frame system with gypsum and aluminum panel exhibited excessive deformation as well as an early collapse of the CFS studs. This observation can lead to an alternative material solution in blast-resistant design.