Shearographic visualisation of bending plate vibrations

Abstract

Holography and speckle pattern interferometry are two typical experimental analysis methods that permit full-field and noncontact measurement of dynamic displacements. The main limitation of these techniques arises from their sensitivity to rigid-body motion and the rapid increase in fringes with displacement, which makes it difficult to interpret fringe pattern. The other disadvantage originates from the small range of their controllable sensitivity, which allows only very small deformations to be measured. Time-average and stroboscopic shearography do not have these limitations and can be effectively applied for vibration analysis of engineering components and structures.