This study evaluates the performance of a new shock tube facility used to produce blast loading in controlled laboratory environments. The facility was found to generate a planar shock wave over the tube cross section by measuring the pressure distribution on a massive steel plate located at the end of the tube. The properties of the shock wave proved to be a function of driver length and driver pressure, and the positive phase of the measured pressure-time histories was similar to those generated from actual far-field explosive detonations. However, the shock tube is also suited to investigate fluid-structure interaction effects and the behaviour of materials in blast events. This was demonstrated using a three-dimensional digital image correlation technique to measure the deformation field of thin steel plates. Synchronization of the threedimensional digital image correlation and pressure measurements enabled a thorough investigation of the entire experiment and identification of fluid-structure interaction effects. Finally, one-dimensional numerical simulations were performed to investigate the wave patterns during the experiments.

This work presents results from an experimental investigation on the influence of stand-off distance on the dynamic response of thin ductile plates subjected to airblast loading. The square plates had an exposed area of 0.3 0.3  m 2 and were manufactured from two different materials, i.e., medium-strength steel and low-strength aluminium. The airblast loading was generated by detonating spherical charges of plastic explosive at various stand-off distances relative to the centre of the plates. Piezoelectric pressure sensors were used for pressure recordings, and synchronized with two high-speed cameras in a stereoscopic setup to capture the response of the targets. The 0.8 mm thick plates were painted with a speckle pattern to measure the transient deformation fields using a three-dimensional digital image correlation (3D-DIC) technique. The tests covered the entire range of structural response from complete failure at the support to a more counter-intuitive behaviour where the permanent mid-point deflection was in the opposite direction to the incident blast wave due to reversed snap buckling. The synchronization of the pressure and displacement measurements enabled a thorough examination of the entire experiment. The trend in all tests was that the maximum response is driven by the positive impulse from the airblast, as it occurred after the positive duration of the pressure pulse. However, depending on the intensity of the blast load and the structural characteristics, elastic effects and the negative phase could play an important role in the final configuration of the plate. Comparison of the permanent deflection and the measurements from digital image correlation confirmed that this technique is capable of accurately measuring the structural response at high loading rates.

The dynamic response of blast-loaded steel plates is studied both experimentally and numerically. The blast loading was generated using a shock tube facility. This is an alternative to explosive detonations where the blast intensity is easily controlled through the initial conditions in each experiment. Massive and deformable steel plates where located at the tube end during testing, where the massive-plate tests served as a basis for comparison with respect to fluid-structure interaction (FSI) effects. Special focus was placed on the influence of pre-formed holes on the dynamic response and failure characteristics of the deformable plates. The plates had an exposed area of 0 0.3 m .3 m  and the tests covered a wide range of structural responses from large inelastic deformations to complete tearing along the diagonals of the plates. Numerical simulations were performed in the finite element code EUROPLEXUS, where the plate was uniformly loaded by the pressure measurements from the massive-plate tests. The plate deformation and the observed crack propagation were successfully recreated by using element erosion and adaptive mesh refinement in the plate, driven by the damage parameter in the material model. As expected, the simulations overestimated the plate deformations due to the underlying assumption that the blast pressure was uncoupled from the deformation (i.e., neglecting FSI). It was also found that the modelling of the realistic boundary conditions with clamping frames, contact and friction was essential to predict the experimental results.

The inelastic response of thin aluminium and steel plates subjected to airblast loading is studied numerically and validated against experimental data. Special focus is placed on the influence of elastic effects and negative phase on the structural response. The blast loading was varied by detonating spherical charges of plastic explosives at various stand-off distances relative to the centre point of the plates. The numerical results obtained with the finite element code EUROPLEXUS were in good agreement with the experiments and predicted the entire range of structural response from complete tearing at the supports to a more counter-intuitive behaviour (CIB) where the final configuration of the plate was in the opposite direction to the incident blast wave due to reversed snap buckling (RSB). RSB attracted special attention since this is an unstable configuration sensitive to small changes in the loading and in structural characteristics. The negative phase of the blast pressure is usually neglected in blast-resistant design. However, the numerical simulations showed that the negative overpressure dominated the structural response and led to RSB at some loading and structural conditions. Two distinctive types of CIB were identified and both were found to depend on the timing and magnitude of the peak negative overpressure relative to the dynamic response of the plates. The study also revealed that CIB may occur in thin plates when the negative impulse is of the same order of magnitude as the positive impulse. The partial and complete failure along the boundaries observed in some of the tests was also successfully recreated in the simulations by using an energy-based failure criterion and element erosion.

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