Measuring full-field vibration and dynamic deformation using single time-gated camera stereo-digital image correlation

Quantitative measurement of full-field vibration and dynamic deformation is essential for characterizing the mechanical properties of materials and the dynamic behavior of structures, as well as validating numerical models under dynamic loading. However, capturing high-speed transient events typically faces challenges regarding motion blur and high hardware costs. This study proposes a novel transient deformation measurement method by combining a time-gated imaging technique with single-camera split-screen stereo-digital image correlation (stereo-DIC). The proposed system employs a time-gated CMOS camera featuring nanosecond-scale ultra-short exposures, synchronized with a pulsed laser source, to effectively freeze the motion of high-speed objects and eliminate motion blur. To achieve cost-effective stereo imaging, a four-mirror adapter is adopted to capture binocular views on a single sensor. The established single time-gated camera stereo-DIC (STG stereo-DIC) system was validated through vibration response measurements of a cantilever aluminum plate and full-field deformation analysis of a rotating fan. Experimental results demonstrate that the first three natural frequencies and mode shapes of the plate agree closely with those obtained from conventional high-speed DIC and finite element analysis. Furthermore, the system accurately captured the surface 3D deformation fields of fan blades at various rotational speeds. This work not only introduces a novel technical route for vibration and high-speed deformation measurement but also highlights its strong potential for applications involving objects subjected to both high temperatures and high rotational speeds, such as aero-engine turbine blades.