Toward double-pulse digital shearography

摘要

Abstract: The holographic and photoelastic method have been extensively applied for the analysis of the transient vibrations. Shearography as a relative new technique compared with holography and photoelasticity, provides an alternative method for the measurement of the transient vibration. The special appeal of the shearography is that (a) it can measure strain waves directly on the object surface to be studied (compared with photoelasticity and (b) it is relatively immune to ambient interruptions and provides a wider and more controllable range of sensitivity (compared with holography). Although the ambient interruption is not a critical problem for the transient vibration measurement due to the application of the double pulse technique, the wider and more controllable range of sensitivity makes it possible to measure the relative large vibration which is beyond the measuring range of holography. In this paper, these measuring methods are compared and the developmental steps of shearography for the transient vibration measurement are represented.!19