Image-transfer and optical technique for residual-strain measurement

The image-transfer and optical technique that was developed for the measurement of residual strain (permanent set) is herein described. This technique is mainly being used for the measurement of residual strains in metallic structures after they have been loaded at elevated temperature. Some evaluation tests on a beam and shell at room temperature and on a bar at elevated temperature are discussed. These tests indicate that the method is adequate for its intended use.