# 배관에서 상반 정리를 활용한 비틀림 파의 산란 신호 진폭의 닫힘 해 계산 연구

Lee, Jaesun;Cho, Younho;Achenbach, Jan D.
이재선;조윤호

• Accepted : 2016.05.19
• Published : 2016.07.01
• 18 19

#### Abstract

Guided waves can be used for the inspection of long range pipelines. Surface corrosion is often found as a major defect type in pipelines. The reciprocity relation is a well-established theorem by which one can simplify complicated mathematical expressions. The approach has been already applied to plate and half-space structures to obtain the closed-form solutions of scattered amplitude. However, results for the case of cylindrical structures have not been reported yet. In this paper, the scattering of torsional waves, which is widely used in commercial applications, is explored by the reciprocity theorem approach. Obtaining closed-form solutions of the amplitudes of propagating waves is much simplified by using the reciprocal relation. The scattered amplitudes for elliptical and rectangular defect shapes are calculated with respect to defect depth and width, at frequencies between 0 and 500 kHz. The amplitude shows the periodic result as a function of frequency. The derived closed-form solutions can play a significant role in quantitative signal interpretation.

#### Keywords

Guided Wave;Reciprocity Theorem;Torsional Wave Mode;Corrosion;Scattered Wave;Closed Form Solution

#### References

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#### Acknowledgement

Supported by : 미래창조과학부, 한국연구재단