Internal crack detection based on thermal excitation enabled digital image correlation method

Abstract

Internal crack detection is a challenging but important part of strength assessment and health monitoring. This paper proposes the use of thermal flow excitation enabled digital image correlation method to obtain full-field deformation for detection of internal crack. In this method, thermal excitation was used to heat the specimen and digital image correlation was applied to measure the strain field. The inner crack could be indicated by the strain concentration in the strain field. The experimental results show that the proposed method can effectively detect the internal cracks (fabricated by fatigue test) in 304 stainless steel material. Finally, a piece cut from the dry gas desulfurization absorber tower with cracks were detected, and the results showed that the thermally stimulated digital image correlation method can detect inner crack in the metal material near the surface and is a promising method for internal crack damage detection.