The influence of boundary conditions on the loading of rectangular plates subjected to localised blast loading – Importance in numerical simulations

A series of localised blast loading experiments are performed in order to understand how the experimental set-up influences the impulse imparted to a plate. The imparted impulse is measured using a ballistic pendulum. The experimental results show that for both rigid and deformable plates the impulse measured by a ballistic pendulum increases as the height of the boundary (clamps) increases. Significantly, it is found that although the measured impulse varies as a function of the boundary height, the plate deformation is unchanged. This suggests that not all of the impulse measured by the ballistic pendulum resulted in plate deformation. Therefore, in numerical and analytical modelling, the total impulse from the ballistic pendulum should not simply be applied as a centrally localised pressure load. Numerical simulations of localised blast loading in combination with the aforementioned experimental results are used to develop a localised blast loading model. The loading model is a simplified pressure loading model which only imparts the deformation causing impulse as opposed to the total ballistic pendulum impulse. The model is validated using an independent set of localised blast load experiments on clamped mild steel plates. Results obtained using a published localised blast load model are also compared.