本論文以羅倫茲力(Lorentz Force)的方式於PVC(Polyvinyl chloride)薄板上激發藍姆波。本研究以LIGA (Lithographie GaVanoformung Abformung)標準製程於PVC基材上成長單、雙面之金屬繞線結構(Meander Line Structure)，線寬設計分佈在0.6~1 mm之間，該結構將置於一均勻橫向磁場之下，並透過施加特定頻率之交流電流，使之與磁場交互作用因而產生縱向之勞倫茲力，也因此可於PVC基材上產生對稱與反對稱模態之藍姆波波傳現象。透過藍姆波波傳理論可設計特定尺寸之金屬繞線結構，激振模態的部分，本論文鎖定激振頻率分別為82、125與225 kHz之非對稱模態與520 kHz之對稱模態藍姆波。藍姆波的量測，係利用單點、小感測面積之錐形超音波換能器(Conical Transducer)，可於PVC薄板不同位置上量測震動訊號，所記錄之波形資料將經過SASW (Spectral Analysis Surface Wave)訊號分析法處理，因此可進一步得到特定頻率下之對稱與反對稱藍姆波波速，實驗與理論計算結果證實羅倫茲力可成功激發藍姆波波傳現象。

The thesis investigates the generation of Lamb waves on PVC (Polyvinyl chloride) substrates using current-induced Lorentz force. Standard LIGA (Lithographie GaVanoformung Abformung) process was used to fabricate single and double side meander line structures which have line width around 0.6~1 mm on PVC substrates. The meander line structure was placed under a transverse permanent magnetic field and was excited by an alternative current which has a specific frequency. Then the longitudinal Lorentz force was generated to excite symmetric and anti-symmetric modes of Lamb waves.
Through Lamb wave theorem, a meander line structure with a specific line width was designed to excite a specific frequency of Lamb wave. In anti-symmetric mode, the resonate frequency of meander line structure with a line width of 0.6 mm, 0.8 mm and 1 mm was 82, 125 and 225 kHz, respectively. In symmetric mode the resonate frequency was 520 kHz at line width of 1 mm. Conical transducer which had the advantage of a point sensing area was use to measure the vibration signal of Lamb wave on different point of the PVC substrates. The Spectrum Analysis Surface Wave (SASW) method was used to analyze the received data to verify the wave velocity of anti-symmetric and symmetric modes. Through the comparison between experimental and theoretical wave velocity, the thesis prove the Lamb wave could be excited by Lorentz force induced by an electrical current in meander line structures.

[1] J. D. Achenbach, “Wave propagation in elastic solids”, North-Holland Publishing Company, New York, (1973)
[2] S. S. Li, T. Okada and X. M.Chen, ” Electromagnetic Acoustic Transducer for Generation and Detection of Guided Waves”, Japanese Journal of Applied Physics, Vol. 45, No. 5B, pp. 4541–4546, (2006).
[3] J. P. Joule, ‘‘On the effects of magnetism upon the dimensions of iron and steel bars”, Philos. Mag III, 30, 76, (1847).
[4] E. Villari, ‘‘Change of magnetization by tension and by electric current,’’ Ann. Phys. (Leipzig) 126, pp. 87–122, (1865).
[5] S. H. Cho, K. H. Sun, J. S. Lee and Y. Y. Kim, “The measurement of elastic waves in a non-ferromagnetic plate by a patch-type magnetostrictive sensor”, SPIE, Vol.5384, pp. 120-130, (2004).
[6] M. Madou, “Fundamental of microfabrication” by CRC press, New York, (1999)
[7] 蘇葵陽, ”實用電鍍理論與實際”,復文書局, (1999)
[8] 林資彬, ”微小壓電式錐形感測器:製作、測試與應用”，國立成功大學機械工程研究所碩士論文, (2005)
[9] T. T. Wu, Y. C. Chen, “Dispersion of laser generated surface waves in an epoxy-bonded layered medium”, Ultrasonics, 34, pp.793-799, (1996)
[10] 曾俊豪，”光柵投射式雷射超音波量測系統及應用”，國立成功大學機械工程研究所碩士論文, (2002)
[11] S. Wolfgang and Y. H. Pao, “On the determination of phase and group velocities of dispersive waves in solids”, J. Appl. Phys., Vol.49, No.8, pp.4320-4327, (1987)
[12] R. Murayama and K. Mizutani, “Conventional electromagnetic acoustic transducer development for optimum Lamb wave modes”, Ultrasonics, 40, pp.491-495, (2002)