Investigation of effect of polyurea on response of steel plates to impulsive loads in direct pressure-pulse experiments

We summarize the results of the response of monolithic steel plates and steel-polyurea bilayer plates to impulsive blast loads produced in direct pressure-pulse experiments, focusing on the deformation and failure modes of the plates. In these experiments, an impulsive pressure pulse is applied to a steel plate through water or soft polyurethane that simulates shock loading with a peak pressure of 80 MPa and duration of 50 ls, followed by a cavitation period and a post-cavitation peak pressure of 40 MPa and 400 ls duration. The pressure pulse is produced by a projectile that impacts either a confined wateror soft polyurethane-layer which in turn transmits the pulse and loads the sample supported by a hollow steel cylinder. Using high-speed photography, the deformation and fracturing of some of the plates are also captured. In addition, the total force acting on the steel plate is measured as a function of time in several selected cases. The experimental results suggest that the presence of polyurea on the back face (opposite to the load-receiving side) of the steel plates can enhance the energy absorption of the plates and help to mitigate their failure. On the other hand, when polyurea is placed on the front face (load-receiving side), it will magnify the initial shock effect and promote failure. These experimental results are paralleled by numerical simulations of the entire experiment, employing physics-based models for the DH-36 steel and polyurea (Amini et al., 2010b. 2009 Published by Elsevier Ltd.