A new full-field motion compensation technique for infrared stress measurement using digital image correlation

Abstract

A new full-field motion compensation technique based on digital image correlation was developed for infrared thermoelastic stress measurements. Speckle patterns with variable infrared emissivity were applied to a test sample for motion analysis. Infrared images of the speckle pattern were acquired under the same loading conditions as for thermoelastic stress measurement. Displacements and deformations on the test sample were analysed using digital image correlation based on information on movement of the speckle patterns. Full-field motion compensation was performed in subsequent thermoelastic stress measurements based on the results of displacement measurements. The feasibility of the proposed motion compensation technique is demonstrated experimentally for thermoelastic stress measurement and identification of local plasticity at the stress-concentrated area in a plate specimen with a circular hole.