Full-field deformation and strain measurement of vehicle body under high-speed impact

A crash test is a common method to evaluate passive vehicle safety, but its full-field deformation and strain is difficult to measure due to instantaneous large deformation during the intense impact process. By means of high-speed cameras, a full-field deformation and strain measurement under high-speed impact is presented based on digital image correlation and binocular stereo vision. To deal with weak correlation in image matching caused by optical noise and large deformation, a controllable Gaussian filter and adaptive light intensity coefficients are used to suppress image intensity interference introduced by optical noise. In addition, based on deformation continuity of the neighboring states, images before and after large deformation are matched by the minimization of reference datum and transfer of deformation coefficients. Finally, full-field deformation and strain data are obtained from an impact test on an engine cover made from DC04 steel. Results show that the deformation measurement accuracy of the method can achieve 0.03 mm within a 500  ×  400 mm² field of view. This study solves the problems of limited measurement points and low efficiency both in the contact measurement method by displacement sensors and traditional optical measurement by the detection of artificial target points, and provides a scientific basis for quantitative analysis of vehicle impact safety, vehicle body structure and material improvement, and finite element simulation of impact theory. (paper)