Numerical study of the effect of polyurea on the performance of steel plates under blast loads

We present the results of our numerical simulation of the dynamic response and deformation of 1 m diameter circular DH-36 steel plates and DH-36 steel-polyurea bilayers, subjected to blast-like loads. Different thicknesses of the polyurea are considered and the effect of polyurea thickness on the performance of steel plates under blast loads is investigated. For each polyurea thickness, we have simulated three cases: (1) polyurea cast on the front face (loading face); (2) polyurea (of the same thickness) cast on the back face; and (3) steel plate of a suitable thickness such that the areal density remains the same in all three cases. Two types of loading are applied to the polyurea-steel system: (1) direct application of pressure on the bilayer system, (2) application of pressure through a separate medium (soft polyurethane or water). The resulting differences are demonstrated and discussed throughout the paper. For the constitutive properties, we have used physics based and experimentally-supported temperature-and rate-sensitive models for DH-36 steel and polyurea, including, in the latter case, the pressure effects. Results from the simulations reveal that, when the polyurea layer with enough thickness is cast on the back face of the plate, the bilayer demonstrates superior performance relative to the other two cases. The differences become more pronounced as the polyurea thickness (maintaining the same areal density in the three cases) becomes greater. The dynamics response of steel plates and metal sheets has been a topic of interest for many years. Numerous applications of steel plates in defense, marine, aviation and car industries have called for a thorough investigation of the dynamic response, and failure and fracturing of steel plates under various loading conditions. For this, in addition to direct experiments, analytical, experimental, and numerical methods have been employed. Theoretical attempts to address this problem go back to 1940s, when Taylor (1975) and Richardson and Kirkwood (1950) investigated the plastic deformation of thin steel plates subjected to underwater explosion. Several reviews have been written on dynamic plastic behavior of steel Early approaches considered only bending action and predicted small deflections. Further studies, some using energy methods, added membrane effects and membrane stretching action to bending effects and assumed different shape modes to predict larger deformations. Wierzbicki and Nur-ick (1996) have solved the initial boundary-value problem by eigenfunction expansion method to predict the early motion of steel plates, and, combining this with a modal solution for late motion, have arrived …