High temperature displacement and strain measurement using a monochromatic light illuminated stereo digital image correlation system

This paper describes full-field, three-dimensional, non-contact measurements of displacement and strain under high temperature condition based on digital image correlation (DIC). To conduct DIC measurements at high temperatures, two important factors need to be considered: (1) the ability of the coating to resist heat and withstand deformation without cracking or peeling off; (2) the radiation from the specimen's surface at high temperature. This paper proposes a solution to both of the most important issues in high temperature DIC measurement. First, different coating materials were investigated, and a procedure to generate a necessary speckle pattern required by DIC to resist heat and withstand deformation at high temperature has been developed. Second, a monochromatic illumination system in combination with a filter set has been studied to eliminate the radiation effect. A DIC system which enables a high temperature displacement and strain measurement up to 1100 °C is presented and demonstrated by experimental measurements.