High Speed Photography and Digital Image Correlation for the Study of Blast Structural Response

摘要

The blast response of structures is difficult to measure because of the high speed and transient nature of the deformation and also because of the severity of shock effects. Measurement approaches using strain gauges and accelerometers provide pointwise information only and may be adversely influenced by shock-related noise. High speed photography in combination with digital image correlation, however, allows full-field, noncontact measurements of the dynamic response of structures and structural components to blast forces. The fundamental concepts and requirements for image correlation measurements are briefly described along with results of displacement accuracy tests. Dynamic measurements of blast response are presented for a steel witness plate, a thin aluminum panel, and a section of aircraft skin in the cargo bay of a commercial aircraft. The spatial and temporal characteristics of the transverse deflection and in-plane strain for these test surfaces are presented and discussed. Imaging frame rates in the range 9,000-10,000 frames per second are used to measure transverse surface deflections and velocities as large as 150 mm and 300 m/s, and plastic strains in excess of 8%.