DOI QR코드

DOI QR Code

Determination of the Group Velocity and Source Location of Dispersive Plate Waves using Wavelet Transform

Wavelet 변환을 이용한 분산성 판파의 군속도와 음원 위치 결정

Jang, Yeong-Su;Jeong, Hyeon-Jo
장영수;정현조

  • Published : 2000.04.01

Abstract

The plate waves propagating in thin plates have dispersive nature showing the dependence of velocities on the frequency. Wavelet transform (WT) using Gabor function can be used to analyze the dispersive waves in the time-frequency domain, and then to find the arrival time of the waves propagating in the plate. Plate waves in the aluminum plate of 3 mm thickness were identified and generated by pencil lead breaks and the lowest order symmetric ($S_o$) and antisymmetric ($A_o$) modes were analyzed by the WT method. The measured group velocities agreed very well with theoretical predictions in the frequency range of 50-400 kHz. The pencil breaks were also used to simulate acoustic emission sources in the plate, and the source location algorithm using the wavelet transform of dispersive plate waves was found to give accurate results.

Keywords

Wavelet Transform;Plate Wave;Dispersion;Fourier Transform;Time-Frequency Analysis;Group Velocity;Source Location

References

  1. Burrus, C. S., Gopinath, R. A., and Guo, H., 1998, Wavelets and Wavelet Transforms, Prentice Hall, New York, NY
  2. Ziola, S. M., and Gorman, M., 1991, 'Source Location in Thin Plates Using Cross- Correlation,' Journal of the Acoustic Society of America, Vol. 90, No. 5, pp. 2551-2556 https://doi.org/10.1121/1.402348
  3. Suzuki, H., Kinjo, T., Hayashi, Y., Takemoto, M., and Ono, K. 1996, 'Wavelet Transform of Acoustic Emission Signals,' Journal of Acoustical Emission, Vol. 14(2), pp. 69-84
  4. 장경영, 이원흠, 김달중, 1998, '전파속도를 알수 없는 재료에서의 AE 발생위치 온라인 측정,' 대한기계학회 논문집(A), 제22권, 제3호, pp. 62, 688-694
  5. Tobias, A., 1976, 'Acoustic-emission source location in two dimensions by an array of three sensors,' Non-Destructive Testing, Vol. 9, pp. 9-12 https://doi.org/10.1016/0029-1021(76)90027-X
  6. Kishimoto, K., Inoue, H., Hamada, M., and Shibuya, T., 1995, 'Time Frequency Analysis of Dispersive Waves by Means of Wavelet Transform,' Journal of Applied Mechanics, Vol. 62, pp. 841-846
  7. Prosser, W. H., Jackson, K. E., Kellas, S., Smith, B. T., Mckeon, J., and Friendmen, A., 1995, 'Advanced Waveform-Based Acoustic Emission Detection of Matrix Cracking in Composites,' Materials Evaluation, Vol. 53 pp. 1050-1058
  8. Rogers, W. P., 1995, 'Elastic Property Measurement using Rayleigh-Lamb Waves,' Research in Nondestructive Evaluation, Vol. 6, pp. 185-208 https://doi.org/10.1007/BF01606381
  9. 조윤호, Rose, Joseph L., 1996, '대형 구조물의 비파괴검사를 위한 유도초음파 모드특성에 관한 연구,' 한국 비파괴검사학회, 추계학술대회 논문집, pp. 93-101
  10. Achenbach, J. D., 1975, Wave Propagation in Elastic Solids, NorthHolland Publishing Company
  11. Graff, K. F., 1975, Wave Motion in Elastic Solids, Ohio State University Press