本文利用電腦輔助設計軟體建構出吉他完整的琴體模型，利用電腦輔助工程軟體進行模態分析，找出自然模態以及自然頻率。施加外力進行簡諧分析，計算出導納級別值並繪出導納圖，接著以文獻中吉他品質好壞的標準做參數改變的品質討論，並以有限元素法、振動力學、彈性力學的理論去分析。
在面板組合件方面，結果顯示有配置琴橋的面板可以去除一些對發聲沒有助益的橫向振動模態，材料參數改變中以纖維方向的楊式係數和密度對自然頻率影響最大，力木數量對重要模態的形成有很大的影響。在完整吉他琴體方面，結果顯示琴橋的側翼長度較短、琴橋在面板上的放置位置越靠近底部，以及只改變琴橋中央或側翼的高度，都可以使吉他的品質提升，如果同時改變側翼和中央高度，則是相對於標準琴橋尺寸，變厚或變薄都可提升音色的品質。

In this thesis, a full model of guitar body is constructed. The free vibration of the structure is performed by using the finite element analysis to obtain the natural frequencies and mode shapes. In order to evaluate the quality of the guitar, the mobility quantities at the edge of the sound hole and the bridge where a unit force is applied are calculated from the harmonic vibration analysis. Several parameters, such as the material properties of the soundboard, the size and geometry of the bridge, and the arrangement of the braces attached to the soundboard, that affected the quality of guitar will be considered in this study.
The results show that the function of using the bridge attached to the soundboard is to eliminate the vibration mode along the direction of the bridge. The Young’s modulus along the fiber direction and the density of the wood are the main factors to influence the natural frequencies. The important third mode shape, in which the amplitude at the sound hole is higher, appears if three braces or more are employed. Moving the location of the bridge downward is recommended. Thicker bridge and/or shorter bridge wings provide better quality.

[1]游步斌，新世界台灣吉他製作工藝大全集，巨石文化，2004。

[2] J. Meyer, “The function of the guitar body and its dependence upon constructional details”, Publications Royal Swedish Academy of Music, Vol. 38, 77-100, 1983.

[3]J. Meyer, “Quality aspects of the guitar tone”, Publications Royal Swedish Academy of Music, Vol. 38, 51-75, 1983.

[4] A. Ezcurra, “Influence of the material constants on the low frequency modes of a free guitar plate ”, Journal of sound and vibration, Vol. 194(4), 640-644, 1996.

[5]J. A. Torres, and R. R. Boullosa, “Influence of the bridge on the vibrations of the top plate of a classical guitar”, Applied Acoustics , Vol. 70, 1371-1377, 2009.

[6]M. J. Elejabarrieta, A. Ezcurra, and C. Santamaria, “Coupled modes of the resonance box of the guitar”, Journal of the Acoustical Society of America, Vol. 111,2283-2292, 2002.

[7]鄭德淵，音樂的科學，大陸書店，2003。

[8] H. H. Lee, “Finite Element Simulations with ANSYS Workbench 12 Theory-Applications-Case Studies”.

[9]N. H. Fletcher, and T. D. Rossing, “The Physics of Musical Instruments”, Springer-Verlag, 1991.

[10]唐林，張永德，陶純孝，音樂物理學導論，中國科學技術大學出版社。

[11]M. H. Sadd, “Elasticity: Theory, Applications, and Numerics”, Academic Press, 2009.

[12]R. Inta, “The acoustics of the steel string guitar”, PhD Thesis, The University of New South Wales, Australia, September, 2007.

[13]劉成群、張超群，汽車振動與噪音(第二版)，新文京開發出版股份有限公司，台北縣，2006。

[14]E. V. Jansson, “Acoustics for the guitar maker”, Publications Royal Swedish Academy of Music, Vol. 38, 27-50, 1983.

[15]O. Christensen, and B. B. Vistisen, “Simple model for low-frequency guitar function”, Journal of the Acoustical Society of America, Vol. 68(3), 758-766, 1980.

[16]R. M. French, “Engineering the Guitar”, Springer , 43-76, 2009.

[17] R. M. French, “Technology of the Guitar”, Springer, 251-277, 2012.

[18]M. J. Elejabarrieta, A. Ezcurra, and C. Santamaria, “Evolution of the vibrational behavior of a guitar soundboard along successive construction phases by means of the modal analysis technique”, Journal of the Acoustical Society of America, Vol. 108, 369-378, 2000.

[19]林冠廷，全尺寸小提琴有限元素模型之建立，國立成功大學機械工程學系碩士論文，2012。

[20]J. Bretos, C. Santamaria, and J. A. Moral, “Vibrational patterns and frequency responses of the free plates and box of a violin obtained by finite element analysis”, Journal of the Acoustical Society of America, Vol. 105, No. 3, 1942-1950, 1999.

[21]I. M. Firth, “Physics of the guitar at the Helmholtz and first top‐plate resonances”, Journal of the Acoustical Society of America, Vol. 61, No. 2, 588-593, 1977.

[22]T. Sumi, and T. Ono, “Classical guitar top board design by finite element method modal analysis based on acoustic measurements of guitars of different quality”, Acoustical Science and Technology, Vol.29(6), 381-383, 2008.