The Influence of Synthetic Gelatine on the Transient Loading and Response of Aluminium Panels Subjected to Blast Loading

This thesis has investigated the influence synthetic gelatine has on the structural response of aluminium panels from blast loading. To support this investigation, the compressive properties of synthetic gelatine in quasi-static and high-strain rate loading were characterised. Quasi-static compressive properties were determined experimentally using uniaxial compression experiments. The surface finish was found to affect the repeatability of these results, and friction was found to affect the stiffness response. Split-Hopkinson-pressure-bar experiments were conducted to explore high-strain rate loading. The experiments proved challenging at low velocities, with stress equilibrium not always being reached. The experiments found that the peak stress increased as the strain rate of the experiment increased. A numerical model was created for both these loading conditions, and good agreement was found with the experiments.

A novel experimental setup was developed using stereo-imaging to measure the effect synthetic gelatine has on the response of a clamped aluminium plate to an explosion. The addition of gelatine reduced the peak displacement and velocity of the target plate. It was also found to increase the time to peak displacement and velocity. These effects increased as the thickness of synthetic gelatine was increased. The gelatine was found to cause a lot of oscillations of the plate long after the loading had finished, lasting over 50 ms. The experimental setup was adapted to investigate the behaviour of deformable plates and synthetic gelatine in buried explosions. The plate responded later in the buried tests, but the peak transient displacement and velocity were found to be the same for a free-air and a buried charge. Showing that a shallow buried charge produces a similar effect on the target plate as the equivalent free-air charge in far-field explosions.

A simplified numerical simulation of blast-loaded hybrid gelatine/aluminium panels was developed to investigate the influence of gelatine on loading further. The model was found to correlate well with the free-air experimental data. Stresses were found to propagate across the width of the gelatine in the model, possibly causing the complex oscillations seen in the plate velocity data. This numerical model is a step toward understanding how a blast wave from an explosion propagates through synthetic gelatine.