## 3 3D DIC in Blast and Shock Loading
The authors show that the plates deformed with the out-of-plane motion centred on the centre of the plate, forming an approximately symmetric dome shape. The out-of-plane velocity begins in the centre of the plate and remains localized around the plate centre, reaching a maximum while the plate deflection is still low. The velocity drops to zero at the same time as the maximum deflection occurs. The principle strain first occurs in the central area of the plate, with a dome shaped strain localization zone appearing in the central area and spreading rapidly outwards towards the boundary region. From this time, another concentric strain zone forms near the boundary region and spreads rapidly inwards towards the plate centre. The highest strains are reported in the area close to the clamped region. The authors reported that the plates only experienced inelastic deformation and no tearing or shearing. In addition, the authors show that the titanium alloy exhibited significantly smaller deformations than the copper or brass specimens, implying that the Ti 50A titanium alloy exhibited far better resistance to dynamic deformation. [PERSON] et al. [56] examined the response of thin aluminium and steel plates subjected to airblast loading. The aluminium and steel plates had a thickness of 0.8 mm and were clamped to a rigid frame, to attempt to create fixed boundary conditions. The steel plates were made from Docol 600 DL, a medium strength, high-hardening and cold-rolled sheet, and the aluminium plates made from EN AW 1050A-H14 alloy, a low-strength, strain-hardened and cold rolled sheet. The air blast was created with a spherical mass of C4 plastic explosive with a mass of 30 g and diameter of approximately 34.5 mm. The standoff distances were 0.125 m, 0.250 m, and 0.375 m for the steel plate and 0.250 m, 0.375 m, 0.50 m and 0.625 m for the aluminium plate. [PERSON] et al. used a pair of Phantom v1610 high-speed cameras (Vision Research Inc., Wayne, NJ, USA) running at 21,000 FPS to capture the imagery for the 3D DIC and an in-house code to process the imagery to obtain deflection, strain and strain rate information. The authors define three types of dynamic elasto-plastic structural response. Type 1 is where the structure oscillates on both sides of its original configuration with a positive (away from the blast origin) final deflection. Type 2 is characterized by more intense pulses, causing oscillation only on the positive side of the original configuration. Finally, type 3 is where the structure may first deform in the positive direction and continue to rebound to the negative side of the original configuration. Type 3 is very rare and extremely sensitive to the structural and loading parameters. All of the steel plates experienced severe plastic deformation, due to the blast load and the fact that the elastic rebound became smaller as the load-intensity increased. The steel specimens with the 0.125 m and 0.250 m standoff both exhibited type 2 structural response. The steel specimens with the 0.375 m experienced reverse snap buckling during the elastic rebound, oscillating in the opposite direction to the direction of travel of the incident wave. In comparison, the aluminium panels at the closest standoff distance experienced complete failure of the plate boundary, resulting in the plate being torn out of the clamping frame. [PERSON] et al. showed that a transition between large inelastic deformation and complete tearing at the plate boundary occurs at a standoff distance of 0.375 m. The largest standoff distances of 0.50 m and 0.625 m resulted in large inelastic deformation (type 1) and reversed snap buckling (type 3) [56]. [PERSON] et al. [57] performed a study examining the response of glass fibre reinforced polymer (GFRP) and foam sandwich structures to explosive air blasts. The face sheets of the sandwich structures were 2 mm thick GFRP and the cores were 40 mm thick foam made from styrene acrylonitrile (SAN), polyvinylchloride (PVC) or polymethaacrylamide (PMI).