Integrity Evaluation of Pipe Welding Zones using Wavelet Transforms, and Specific Sensitivities based on SH-EMAT Pulse-Echo Method

다국어 초록 (Multilingual Abstract)

Pipes in facilities contain lots of welding zones and requires automated ultrasonic inspection. An electromagnetic acoustic transducer(EMAT) can be usefully applied in an automated ultrasonic inspection system. In this study, shear horizontal waves (SH-waves)generated by EMAT were implemented for the inspection of pipe welding zones. In analyzing of SH-EMAT signals, wavelet transformswere useful to extract key information. The intensity of the directly transmitted signal was used as a reference signal. A ratio of thereflected signal to the reference was proposed as the specific sensitivity. The sizes of defects were evaluated quantitatively using thespecific sensitivity.

참고문헌 (Reference)

1 김대현, "웨이브렛 변환과 SH-EMAT을 이용한 배관 용접부 결함 검출" 대한기계학회 36 (36): 1511-1519, 2012

2 이진혁, "수평횡파 송수신용 EMAT를 이용한 스틸 박판의 두께 감육 평가" 한국비파괴검사학회 31 (31): 47-52, 2011

3 이진혁, "발전소 열교환기 헤더와 튜브의 부분 용입형 용접부 초음파 자동검사시스템 개발" 한국비파괴검사학회 30 (30): 367-372, 2010

4 Achenbach, J., "Wave Propagation in Elastic Solids" Elsevier 10-59, 1984

5 Rose, J. L., "Ultrasonic Waves in Solid Media" Cambridge University Press 241-259, 1999

6 Park, I. K, "Time-Frequency Analysis of Lamb Wave Mode" 10 (10): 133-140, 2001

7 Salajegheh E., "Time History Dynamic Analysis of Structures using Filter Banks and Wavelet Transforms" 83 : 53-68, 2005

8 Siqueira, M., "The Use of Ultrasonic Guided Waves and Wavelets Analysis in Pipe Inspection" 41 (41): 785-797, 2004

9 Mertins, A., "Signal Analysis: Wavelets, Filter Banks, Time-Frequency Transforms and Applications" Wiley 210-226, 1999

10 Lei, K, "Research on Weak Signal Detection Technique for Electromagnetic Ultrasonic Inspection System" 2394-2399, 2008

11 Park, I. K., "Non-Contact Ultrasonic Inspection Technology of Fillet Weldments Monitoring" 321 : 513-517, 2006

12 Gori, M., "Guided Waves by EMAT Transducers for Rapid Defect Location on Heat Exchanger and Boiler Tubes" 34 (34): 311-314, 1996

13 Soto-Cajiga, J., "Fpga-based Architecture for Real-Time Data Reduction of Ultrasound Signals" 52 (52): 230-237, 2012

14 Hirao, M, "EMATs for Science and Industry:Noncontacting Ultrasonic Measurements" Kluwer Academic Publisher 13-56, 2003

15 Liu, S., "Diagnosis of Structural Cracks using Wavelet Transform and Neural Networks" 54 : 9-18, 2013

16 Kim, H. W., "Circumferential Phased Array of Shear-Horizontal Wave Magnetostrictive Patch Transducers for Pipe Inspection" 53 (53): 423-431, 2013

17 Fujisawa, K., "Application of EMAT to Steel and Nonferrous Metal" 51 (51): 68-73, 2002

18 Hirao, M., "An SH-wave EMAT Technique for Gas Pipeline Inspection" 32 (32): 127-132, 1999

19 Büssow, R., "An Algorithm for the Continuous Morlet Wavelet Transform" 21 (21): 2970-2979, 2007