Numerical analysis of the influence of the deflector stiffness and geometry on its effectiveness

The aim of the paper is to present the results of numerical analyses of designed classical system for measuring impact of the pressure wave originating from the detonation of explosive charge. In the paper, authors present classical ballistic pendulum in the form of the 1-meter length, HEB220, double T beam, which was suspended on the four parallel steel cables. On the front part of the pendulum, steel deflector was attached, whose aim was to disperse the energy. A few variants of used deflector were prepared, differing in the deflector geometry and thickness of the used material. In the next step, presented system was loaded with use of pressure wave, originating from detonation of 50 grams explosive charge. In order to properly describe the detonation process ConWep method was used. In this method, on the basis of preset geometric and mass parameters, together with TNT equivalent, the pressure pulse is determined. A three dimensional model of classical ballistic pendulum was prepared in MSC Patran software and numerical analyses were performed using LS-Dyna software. As the result of numerical analyses, the maximum deflection of the pendulum was determined for each case. Based on obtained results the influence of deflector geometry and stiffness on energy absorbing was identified and presented in the form of graphs.