Quantitative Evaluation of Pipe Wall Thinning by Electromagnetic Acoustic Resonance

Authors : Toshiyuki Takagi¹, Tetsuya Uchimoto¹
                 Ryoichi Urayama¹, Shigeru Kanemoto²

Company : ¹Institute of Fluid Science,
                     Tohoku University                    
                   ²School of Computer Science and
                    Engineering, The University of Aizu

Country : Japan

Topic :

Non-Destructive
Examination methods

ABSTRACT :

Electromagnetic acoustic resonance method (EMAR) has a high capability of evaluating thickness or ultrasonic velocity, and it is applied to measurement of thickness, elastic constants, damping properties and so on. Since the principle of the method is based on the through-thickness resonances of bulk waves, that is, thickness oscillations, targets are usually limited to ones with simple geometry such as plates. In this study, pipe wall thinning, where the thickness changes on the curved surface, is evaluated by EMAR. For the purpose, several data processing methods are applied to extract thickness information from spectral response. Measured spectra are obtained by an experiment using a carbon steel pipe with two-dimensional elliptic thinning machined by EDM,and results of the data processing are compared in view of accuracy and stability. It turned out that superposition of n th compression of original spectrum give the most stable and accurate evaluations. This result is also supported by the numerical simulation of sonic fields.

Speaker Biographical Information

Toshiyuki Takagi (Dr. of Eng., Professor) is Deputy Director of the Institute of Fluid Science, Tohoku University. His research field includes electromagnetic nondestructive evaluation, plant lifecycle management, and development of intelligent materials. He published more than 250 international and domestic journal papers. He is also Editor-in-chief of International Journal of Applied Electromagnetics and Mechanics.