Dynamic behavior of metallic sandwich panels subject to air-blast explosion

Honeycomb sandwich structures have been investigated for a variety of applications, particularly as blast resistant structures because of their excellent strength to mass ratio. The current study investigates the response of a stainless-steel sandwich panel, with hollow core, foam filled core, and gel filled core under air blast load using Finite Element (FE) analysis. Johnson-Cook (J-C) material model is used to estimate the plastic failure characteristics of steel under air-blast explosion of 1, 2 and 3 kg of trinitrotoluene at a stand-off distance of 100 mm. The air-blast simulation is achieved using the Conventional Weapons Effect Program (CONWEP) code developed by US army corps. A parametric study for the gel filled model is carried out by varying the core thicknesses and the blast-point stand-off distances (SoD) with respect to the front plate deflection (FPD), back plate deflection (BPD), and energy absorption. A strain rate analysis of sandwich structure is conducted for the hollow core and foam core models, wherein the strain rate for the hollow core panel is varied from 0.1/s - low strain rate (LSR) to 3500/s - high strain rate (HSR), and for the foam core model, it is varied from 0.004/s (LSR) to 12,000/s (HSR). It is found that the back plate deflection obtained from the HSR model in both cases is significantly smaller compared to the LSR model.