臺灣博碩士論文加值系統

本論文係針對長距離的管線做非破壞檢測時所使用的蘭姆波，研究其波傳特性及各式模態對缺陷之靈敏性評估。在平板型蘭姆波波傳中，經由理論推導，可發現存在對稱型波傳模態及反對稱型波傳模態。而圓柱管上的蘭姆波亦具有三種波傳模態，即縱向模態、扭力模態及撓曲模態。各型波傳模態，經由求解特徵方程式，可得各個模態之波速與頻率的關係。在實驗上，為應證頻散曲線中各模態波速隨頻率變化之關係，採用304不□鋼板及碳鋼圓柱管，以超音波探頭傾斜入射縱波以激振各式模態。當縱波在波傳介質上達到同相位之建設性干涉時，蘭姆波模態即可被激發出來。於實驗中，量測不同fd值下所激振蘭姆波模態之群波速度值，並將結果與數值理論值做比較分析，發現以此實驗架構方式，可有效的激振蘭姆波的模態產生。此外，在更進一步的研究中，將反應明顯的蘭姆波模態分別在具有缺陷之碳鋼圓柱管及不□鋼平板上，進行缺陷檢測，評估各種模態對缺陷之靈敏度及解析度。其結果顯示不同厚度及頻率之配合(不同fd值造成不同波傳能量分佈)將會對蘭姆波模態之檢測靈敏度及波形外觀造成波形混雜的結果。而利用激振單一模態以進行檢測，可使得回波訊號簡明易分析。另外，選用無頻散現象區域的模態對缺陷進行檢測，可以確保在波傳遞過程中，波形外觀保持一致性，而達到最小的衰減。此實驗量測結果將可作為利用蘭姆波檢測技術的參考依據。

This thesis studies Lamb waves for long-range pipeline inspection. The property of Lamb waves propagation and the sensitivity of defect detection will be evaluated in this thesis. There are two groups of waves propagation in plate, first group of waves are called symmetrical Lamb waves, and the second group are called anti-symmetrical Lamb waves. Furthermore, there are three different mode types exist in hollow cylinder, such as the longitudinal, torsional, and flexural modes. By solving the characteristic equation of the Lamb wave problem, the dispersion character of the Lamb waves can be found.
The phase and group velocity for different Lamb modes obtained from the dispersion curve are also studied in this thesis. In the experimental setup, the longitudinal wave is incident at certain incident angles and velocities to generate Lamb waves propagated on the stainless steel plate and carbon steel hollow cylinder. When the longitudinal waves are in the constructive interference in the medium, only one Lamb wave will propagate. As a result, compare with the measured data and theoretical predictions of the group velocities, it is observed that angle beam longitudinal waves offer an accurate and workable method for Lamb waves generation.
To evaluate the sensitivity and resolution of the Lamb waves testing, additional experiments for detecting defects are carried out in this thesis. It is found that a single and pure Lamb wave is very useful for detection defects. Moreover, selected the non-dispersive Lamb modes for detection can keep the propagating wave shape without changing; also, only minimum energy is decayed as wave propagated.

目 錄I
表 目 錄III
圖 目 錄IV
中文摘要XII
英文摘要XIII
第一章 緒論1
1.1 研究背景1
1.2 文獻回顧3
1.3 研究方法6
第二章 理論分析11
2.1 平板型蘭姆波11
2.1.1 平板上蘭姆波波傳之特徵方程式11
2.1.2 平板型蘭姆波之模態15
2.1.3 平板型蘭姆波之相位速度與群波速度17
2.2 圓柱管型蘭姆波18
2.2.1 圓柱管型蘭姆波之特徵方程式19
2.2.2 圓柱管型蘭姆波之模態20
2.2.3 頻散曲線22
2.2.4 波形結構23
第三章 實驗架構及量測28
3.1 平板上蘭姆波波傳量測實驗29
3.1.1 實驗設備及檢測試片30
3.1.2 平板型蘭姆波實驗之架構32
3.2 圓柱管上蘭姆波波傳量測實驗35
3.2.1 實驗設備及檢測試片36
3.2.2 圓柱管型蘭姆波實驗量測37
第四章 實驗結果與討論49
4.1 平板型蘭姆波量測實驗49
4.2 圓柱管型蘭姆波量測實驗56
第五章 結論與建議87
5.1 結論87
5.2 建議89
參考文獻90
附錄A：圓柱管中波傳模態特徵方程式理論推導93
附錄B：頻散曲線軟體計算程式112
附錄C：實驗量測之蘭姆波模態回波訊號圖形117
附錄D：各蘭姆波模態對缺陷之回波訊號圖形122

1.D.N. Alleyne and P. Cawley, “Long range propagation of Lamb waves in chemical plant pipework,” Materials Evaluation, pp.504-508, 1995.2.P.M. Naghdi and R.M. Cooper, “Propagation of elastic wave in cylindrical shells. Including the effect of transeverse shear and rotatory intertia,” Journal of the Acoustical Society of America, Vol.28, pp.56-63, 1956.3.I. Mirsky and G.J. Herrmann, “Nonaxially symmetric motions of cylindrical shells,” Journal of the Acoustical Society of America, Vol.29, pp.1116-1123, 1957.4.J.A. McFadden, “Radial vibrations of thick-walled hollow cylinders,” Journal of the Acoustical Society of America, Vol.26, pp.714-715, 1954.5.D.C. Gazis, “Three-dimensional investigation of the propagation of waves in hollow circular cylinders. I. Analytical Foundation,” Journal of the Acoustical Society of America, Vol.31, pp.568-573, 1958.6.D.C. Gazis, “Three-dimensional investigation of the propagation of waves in hollow circular cylinders. I. Numerical Results,” Journal of the Acoustical Society of America, Vol.31, pp.573-578, 1958.7.J.E. Greenspon, “Vibrations of thick cylindrical shell,” Journal of the Acoustical Society of America, Vol.31, pp.1682-1683, 1958.8.J.E. Greenspon, “Flexural vibrations of thick-walled circular cylinder according to the exact theory of elasticity,” Journal of the Acoustical Society of America, Vol.32, pp.37-34, 1960.9.J.E. Greenspon, “Vibrations of a thick-walled cylindrical shell-comparison of the exact theory with approximate theories,” Journal of the Acoustical Society of America, Vol.32, pp.571-578, 1960.10.A.H. Fitch, “Observation of elastic-pulse propagation in axially symmetric and nonaxially symmetric longitudinal modes of hollow cylinders,” Journal of the Acoustical Society of America, Vol.35, pp.706-708, 1963.11.J.L. Rose, “Recent advances in guided wave NDE,” IEEE International Ultrasonics Symposium Proceedings. pp.761-770, 1995.12.A. Pilarski, J.J. Ditri and J.L. Rose “Remarks on symmetric Lamb wave with dominant longitudinal displacements,” Journal of the Acoustical Society of America, Vol.93, pp.2228-22230, 1993.13.J.L. Rose and Y. Cho, “A boundary element solution for a mode conversion study on the edge reflection of Lamb waves,” Journal of the Acoustical Society of America. Vol.99, pp.2097-2109, 1996.14.J.L. Rose, H.J. Shin, D. Jiao, S. Pelts and M.J. Quarry, “Guided wave inspection of circumferential cracks,” 6th Annual NDE Issues Meeting, Charlotte N.C., pp.20-22, 1996.15.J.L. Rose, J. Spanner, D. Jiao, “Ultrasonic Guided wave NDE for piping,” Materials Evaluation, Vol.54. pp.1310-1313, 1996.16.D.N. Alleyne, P. Cawley and M. Lowe, “The long range detection of corrosion in pipes using Lamb waves,” Review of Progress in Quantitative Nondestructive Evaluation, Vol.14, p.2073, 1995.17.D.N. Alleyne, P. Cawley and M. Lowe, “The inspection chemical plant pipework using Lamb waves: Defect sensitivity and field experience,” Review of Progress in Quantitative Nondestructive Evaluation, Vol.15, p.1859, 1996.18.D.N. Alleyne and P. Cawley, “The excitation of Lamb waves in pipes using Dry-coupled piezoelectric transducers,” Journal of Nondestructive Evaluation, Vol.15, No.1, pp.11-20, 1996.19.D.N. Alleyne,M. Lowe and P. Cawley, “The Lamb wave inspection of chemical plant pipework,” Review of Progress in Quantitative Nondestructive Evaluation, Vol.16, p.1269, 199720.M. Lowe, D.N. Alleyne and P. Cawley, “Mode conversion of guided waves by defects in pipes,” Review of Progress in Quantitative Nondestructive Evaluation, Vol.16, p.1261, 1997.21.H. Kwun and K.A., “Experimental observation of elastiv-wave dispersion in bonded solid of various configurations,” Journal of the Acoustical Society of America, Vol.99, pp.962-968, 1996.22.D.N. Alleyne, P. Cawley and M. Lowe, “Defect detection in using guided waves,” Ultrasonics , Vol.36, pp.147-154, 1998.23.M.J. Quarry, A time delay comb transducer for Guided wave mode tuning in piping, Ph.D Thesis, the Pennsylvania Stste University, May 2000.24.李克明、劉德榮等，超音波探傷，水利電力出版社，北京，198025.J.L. Rose, K.M. Rajana, and F.T. Carr, “Ultrasonic guided wave inspection concepts for steam generator tubing,” Materials Evaluation, pp.307-311, 1994.26.I.A Viktorov, Rayleigh and Lamb Waves: Physical Theory and Applications, Plenum, New York, 1967.27.M.G. Silk and K.P. Bainton, “The propagation in metal tubing of ultrasonic wave modes equivalent to Lamb waves,” Ultrasonics, Vol.17, pp.11-19, 1979.28.D.N. Alleyne and P. Cawley, “The interaction of Lamb Waves with Defects,” IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, Vol.39, pp381-396, 1992.29.D.N. Alleyne, P. Cawley, “Long range propagation of Lamb waves in chemical plant pipework,” Materials Evaluation, pp.504-508, 1995.30.D.N. Alleyne, M.J.S. Lowe and P. Cawley, “The mode conversion of a guided wave by a part-circumferential notch in a pipe,” Journal of Applied Mechanics, Vol.65, pp.649-656, 1998.31.D.N. Alleyne and P. Cawley, “Optimization of Lamb wave inspection techniques,” NDT&E International, Vol.25, No.1, pp.11-21, 1992.