Crack detection based on a moving mode of eddy current thermography method

As a new emerging nondestructive testing (NDT) method, eddy current thermography is efficient for crack detection and location. In this study, a moving mode of eddy current thermography is proposed. Firstly, the relative mathematical models are provided. Then, Simulation and experimental studies on temperature distribution on a specimen are respectively carried out. A crack feature extraction method, which is called line-scanning method (LSM), is put forward. The optimal position of the scanning line on thermal images is determined and the characteristics of the temperature around the cracks are discussed. The resolution of LSM is obtained, which is useful for determining the moving speed of the specimen. This paper also presents a crack location method of using temperature gradient distribution on specimen surface. Finally, a problem to be solved in the moving mode of eddy current thermography is presented.