APPLICATION OF LASER-GENERATED ULTRASOUND TO EVALUATE WALL THINNED PIPE

The objective of this study is the development of non-contacting technique to evaluate the size of wall-thinned defect using laser-generated guided waves. Therefore, while the conventional studies on guided waves were focused on the long-range inspection for the presence of the defect, this study deals with the local inspection of the area where the defect is apt to generate for a closer defect sizing. For this aim, the non-contacting system of laser with linear slit array and air-coupled transducer was used in order to generate and detect guided waves and carbon steel pipe with elliptical defects which is similar to actual corrosion was adopted as a specimen. As a result, the characteristics of guided waves with varying shape of wall-thinned defect in carbon steel pipe are investigated and consequently the trends of these characteristics are analyzed for evaluating defect sizing quantitatively.