Digital image correlation: A measurement tool for the study of explosive effects

It is difficult to measure the response of a structure to an explosive blast because of the high speed and transient nature of the deformation and also the severity of shock effects. Measurement approaches using strain gages and accelerometers provide point-wise information only and may be adversely influenced by shock-related noise. Further, attached sensors of even small mass can separate from the structure or subtly perturb the local response of lightweight structures. Global or full-field capability is especially important owing to the unpredictable spatial response characteristics. High speed photography in combination with digital image correlation allows full-field, non-intrusive measurements of the high speed dynamic response of structures to blast forces. Image correlation measurements yield transverse and in-plane surface displacement and surface strains. High speed photography and digital image correlation are used to study the elastic and plastic response of flat and curved aluminum panels and planar witness plates to blast forces.