SPECKLE INTERFEROMETRY FOR HIGHLY LOCALIZED DISPLACEMENT-FIELDS

A recent method of obtaining phase fringe patterns of improved quality using electronic speckle pattern interferometry (ESPI) is complemente d by new equations governing the displacement sensitivity if asymmetri c illumination is used. The techniques are experimentally verified. Th e accuracy of the method for determination of highly localized strain fields is demonstrated by comparing the measurements with the results of a finite-element model. The potential of the improved method in the field of fracture mechanics is outlined.