## 3 3D DIC in Blast and Shock Loading
[PERSON] and [PERSON] [39] examined the response of a curved glass fibre reinforced polymer to explosive loading in an underwater environment. The composite plies are composed of e-glass fibres with a [0\({}^{\circ}\)/90\({}^{\circ}\)] biaxial layup, with a vinyl ester matrix resin. The panels consist of 3 plies, bonded by vacuum infusion, giving a finished part thickness of 1.37 mm and 62% fibre content by mass. The convex face of the panels has a radius of curvature of 182.8 mm, with the curved section of the panel being 228.6 mm in diameter. The curved section of the panel is mounted with the convex surface towards the incoming shock front. [PERSON] and [PERSON] chose this geometry as it represents common geometries used in underwater applications (such as submarine hulls). The shock wave is generated by a conical shock tube, initiated by an explosive charge. The high-speed imagery was captured by a pair of Photron SA1 cameras (Photron USA, Inc., San Diego, CA, USA) at a frame rate of 20,000 FPSand the 3D DIC data processed by the VIC-3D software package (Correlated Solutions, Inc., Irmo, SC, USA). One of the main purposes of the experimental component of this study was to obtain data to correlate and validate computational simulations run with a finite element code. The authors did find a high level of correlation between the experimental results and the computational simulations. Their 3D DIC results recorded a peak displacement in the centre of the panel of 80 mm and 55 mm for a point mid-way between the centre and clamped boundary. The peak velocity occurs at the beginning of the event, reaching a magnitude of 20 m/s. The main damage mechanism the authors reported on was delamination between the plies, with minimal fibre rupture or matrix cracking [39]. [PERSON] and [PERSON] [40] conducted experiments looking at five different types of glass panels loaded through a shockwave. The types of panels the authors tested were: clear glass, tempered glass, wired glass, sandwiched glass and laminated sandwiched glass with a protective film on both outside faces. Each specimen was 305 mm \(\times\) 305 mm \(\times\) 6.5 mm (except the laminated sandwiched glass, which was 1 mm thicker due to the protective film on the front and back sides) and made from soda-lime-silica glass. The shock was imparted to the glass panels via a shock tube, with all samples being subjected to the same level of incident pressure. [PERSON] and [PERSON] used a pair of Photron SA1 cameras (Photron USA, Inc., San Diego, CA, USA) running at 20,000 FPS to capture the imagery used in the 3D DIC. The image processing for the 3D DIC was done through use of the VIC-3D software program (Correlated Solutions, Inc., Irmo, SC, USA). The authors show that the laminated glass panel was the only panel to not fail catastrophically, and had the second largest deflection with 1.7% strain. In comparison, the plain glass had a strain of 0.01%, the wired glass, 1%, the tempered glass, 2%, and the sandwich glass with 5% strain before failure. Their results show that the lamination of the sandwich glass significantly improved the blast mitigation properties of the laminate, resulting in delayed deflection and damage propagation to prevent catastrophic failure. The laminated glass panel did experience fragmentation and cracking in the glass, with the protective film containing the glass fragmentation and preventing flying debris. The catastrophic failure of all of the other panels resulted in high-speed fragmentation debris [40]. [PERSON] et al. [41] examined the response of glass-fibre reinforced polymer sandwich panels and laminate tubes to blasts in air and underwater environments. The sandwich panels were made with 2 plies of [0\({}^{\circ}\)/90\({}^{\circ}\)/\(\pm\)45\({}^{\circ}\)] e-glass quadriaxial skins with a styrene acrylonitrile (SAN) foam core (ranging from 30 mm to 40 mm), infused with a Prime-LV epoxy resin.