Effect of bubbles on measurement accuracy of digital image correlation for a stress corrosion test

Considerable errors are encountered when the digital image correlation (DIC) method is used in a stress corrosion test. In this paper, the stress corrosion test system was built first. The applied maximum strain was accurately measured by DIC. Then, the effect of bubbles on DIC measurement results was analyzed. The bubbles induced additional errors in the measurement results, leading to local concentrations in measured displacement and strain fields. Finally, in order to reduce the displacement and strain errors caused by the bubbles, a twice subtraction method (TSM) was developed. The results of the application example show that TSM is an effective method to reduce the effect of bubbles on measurement accuracy of DIC for a stress corrosion test.