Abstract
Development of weapons has increased over the last decade. The explosives are optimized to produce heat and pressure effects. Fortified structures need to be protected from blast wave impact. Armoured doors are used at the fortified structure in order to protect people, weapons, and ammunition from blast waves. Fireball and blast hit a sandwich armoured door which could be damaged by blast wave. In the present study, the prediction of the sandwich armed steel doors performance under the impact of the blast wave effect is highlighted. 3-D model is proposed to study polyurethane foam (RPF) layer to retrofit the sandwich armed steel doors using a 3-D finite element analysis. Hexagonal core sandwich door and stiffener channel sandwich door are used so as to study blast mitigation using the RPF layer. The study presents a comparison between the field test and the finite element analysis to assess the accuracy of the proposed finite element model. The constitutive model for this analysis contains elasto-plastic materials. An elasto-plastic model is employed to represent the armoured doors, the concrete wall of the fortified structure, and the RPF layer. The proposed model is programmed and linked to an available computer program Autodyn3D (2005).
The finite element model takes into account the effects of the blast load, the connection between the armoured doors and the frame fixed to the concrete wall, and RPF layer. The effects are expressed in terms of the displacement-time history of the sandwich armed doors and the pressure-time history effect on the sandwich armoured doors as the explosive wave propagates. A parametric study based on the 3-D nonlinear finite elementanalysis is conducted to study the impact of the RPF layer on the sandwich armed steel door performance. The behavior of the sandwich armoured door of the armoured doors is investigated and presented under the blast waves obtained from detonating 1-kg, 2-kg, and 3-kg TNT at scaled distance of 1 m.