## 3 3D DIC in Blast and Shock Loading
The 3D DIC showed that the initial out-of-plane displacement is approximating a rectangular shape (due to the plate clamping boundary) and evolves into a sinusoidal shape (due to decay of the blast loading and the deformation only being due to the plate inertia). The blast impulse imparts momentum to the aluminium plate during a very short loading period, imparting enough momentum to continuously deform the plate after termination of the loading from the shock wave. The deformation history consists of two major parts, an initial part consisting of highly plastic behavior reaching a maximum displacement, and a second regime of elastic rebound and elastic vibration with damping. The 3D DIC revealed that in the initial stages, the maximum normal strain occurs close to the boundaries, with strains developing in the centre of the plate after inertial forces have taken over. The in-plane strain is initially very small, eventually increasing in the central region of the plate in a typically bi-axial manner. Initially, the maximum stain rates occur close to the clamped boundaries, with the maximum moving to the centre of the plate later in the blast response [45]. [PERSON] [46] conducted a study into the experimental requirements of 3D DIC in a synergistic blast and projectile event scenario. Initially, the authors validated the 3D DIC on an aluminium tensile test, comparing the 3D DIC results to strain gauge data. The authors used a pair of Photron SA5 cameras (Photron USA, Inc., San Diego, CA, USA) for high-speed image capture and the ARAMIS software (GOM GmbH, Braunschweig, Germany) for image processing. After these initial tests, a number of factors to be considered during testing of internal detonations of blast boxes were reported on. To protect the cameras from blast fragmentation, the authors used mirrors with the cameras behind blast protection, as splinter-proof ballistic plexiglass caused the image quality obtained through them to be of low quality. Another area reported on was the consistency of the speckle pattern. The consistency of the pattern can have a significant effect on the accuracy, with areas of singular colour reducing the amount of data obtainable from that location. Once the blast wave impinges on the mirrors, vibration will invalidate any data obtained after this interaction. Lighting is also an important factor reported by [PERSON]. The authors noted that ambient outdoor lighting conditions are sufficient, even in overcast conditions. Too much lighting can lead to overexposure, producing inconsistencies in the light levels and leading to data loss in the 3D DIC system. Both small patches of overexposure and changes in light levels from the reference image can cause a loss of data. Lastly, the authors noted that for highly dynamic events, paint adhesion is critical to prevent data loss during the event [46]. [PERSON] et al. [47] examined the response of curved carbon fibre composite panels to shock wave loading. The panels had a curvature of (i) infinite (flat), (ii) 305 mm, and (iii) 112 mm radius of curvature and are made from 32 layers of carbon fibre with a ([0\({}^{\circ}\)/90\({}^{\circ}\)/45\({}^{\circ}\)/\(-\)45\({}^{\circ}\)]s) layup, giving an overall thickness of 2 mm. The shock wave was generated by a shock tube and three shock pressures were generated, ranging from 3 MPa to 8 MPa. A pair of Photron SA1 cameras (Photron USA, Inc., San Diego, CA, USA) operating at 20,000 FPS was used by [PERSON] et al. to capture the high-speed imagery, and the VIC-3D software package (Correlated Solutions, Inc., Irmo, SC, USA) was used for image processing. The authors show that the failure loading for the panels were (i) 3.65 MPa, (ii) 3 MPa, and (iii) 7.78 MPa. The 3D DIC showed that during the early parts of the loading, the out-of-plane deflection contours were not influenced by the boundary conditions. Later in the loading, the stress waves deflecting off the boundaries cause a change in the deflection contour shape.