簡易檢索 / 詳目顯示

研究生: 戴孟賢
Dai, Meng-Shien
論文名稱: 功能梯度矩形板承受均勻分佈力或集中力的解析解
Analytical Solution of Functionally Graded Rectangular Plates Subjected to Uniform Pressure or Concentrated Load
指導教授: 褚晴暉
Chue, Ching-Hwei
學位類別: 碩士
Master
系所名稱: 工學院 - 機械工程學系
Department of Mechanical Engineering
論文出版年: 2014
畢業學年度: 102
語文別: 中文
論文頁數: 74
中文關鍵詞: 功能梯度材料矩形薄板疊加法有限元素分析
外文關鍵詞: Functionally graded materials, thin plate, superposition technique, finite element analysis
相關次數: 點閱:152下載:4
分享至:
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報
  • 本文以彈性力學的理論推導CCCC-FGM平板的解析解,平板受到不同的外力作用,即均勻分佈負載與集中力。平板為雙層板,上半層為FGM材料,蒲松比為常數,楊氏係數在厚度方向呈S型函數變化(簡稱S-FGM),下半層則為均質材料。使用疊加法,CCCC-FGM平板受到均勻分佈負載或集中力的解析解可由三個子問題疊加而成,他們分別為SSSS-FGM平板受到相同的負載作用與SSSS-FGM平板各別在相反對邊承受未知彎矩。在每一個子問題中,使用Levy’s method (單傅立葉級數展開)與Navier’s method (雙傅立葉級數展開)兩個方法來求得解析解。
    在有限元素分析中,使用20節點的固體元素,並且獲得平板的位移與應力的數值解。在研究中改變的參數有二,包括楊氏係數比值與施加之外力條件,此二參數對於平板力學行為的影響將會詳細地討論。研究結果顯示,雖然解析解在平板中心處的位移與有限元素數值解非常符合,應力在FGM材料楊氏係數變化較劇烈的區域仍不準確,需要更多的元素來模擬使其準確度提高。
    本文的第二部份探討FGM平板與FGM樑的相似性。考慮一平板,其一對邊為簡支撐,另一對邊為自由端,研究結果顯示當蒲松比為零,無論平板長寬比為多少,平板均可視為樑;對於蒲松比不為零的情況,例:ν = 0.3,長寬比越大,平板的力學行為越接近樑 (當長寬比大於15時。)

    Based on the elasticity theory, the analytical solutions of the thin functionally graded plate with four-edge clamped (CCCC FGM plate) are obtained in this thesis. The plate is subjected to uniformly distributed pressure and concentrated load applied at the plate center, respectively. The FGM plate contains two equal-thickness layers, i.e. FGM and homogeneous material. For the FGM layer, the Poisson’s ratio is assumed to be a constant and the Young’s Modulus varies along the thickness direction in Sigmoid function form (called S-FGM). By using the superposition principle, the closed form of the CCCC FGM plate under uniformly distributed pressure or concentrated load can be obtained from three sub-problems. They are the simply-supported-edge FGM plate (SSSS FGM plate) under same load, and two SSSS FGM plates subjected to a pair of unknown bending moment at opposite edges, respectively. In each sub-problem, the Navier’s method and Levy’s method are employed to obtain the analytical solution. The finite element analysis is performed to get the displacements and normal stress fields in the whole plate. The results show that the displacement obtained from the analytical formulation at the center point of the plate is well compared with that from FEM calculation. However, the accuracy of the numerical bending stresses near the region where material changed abruptly is doubtful. The second part of this thesis is to discuss the mechanical similarity of a FGM beam and a FGM plate. Consider a FGM plate with opposite edges free and simply-supported, respectively. It shows that the FGM plate with zero Poisson’s ratio can be treated as the beam for all a/b ratio. For non-zero Poisson’s ratio (say, 0.3), the FGM plate and beam are similar only when a/b ratio getting larger enough (e.g. more than 15.)

    摘要 I Abstract III 誌謝 VIII 目錄 IX 表目錄 XII 圖目錄 XIV 符號表 XVII 第一章 緒論 1 1.1 研究動機 1 1.2 文獻回顧 1 1.3 本文架構 4 第二章 FGM矩形平板之理論基礎 6 2.1 FGM平板之位移場、應變場與應力場 6 2.2 FGM平板的正向力、剪力及力矩之定義 8 2.3 FGM平板之中性面位置 11 2.4 FGM平板之平衡方程式 11 2.5 平板之邊界條件 12 2.6 FGM平板材料性質之函數分佈 14 第三章 CCCC-FGM平板受到不同負載之力學行為 19 3.1 CCCC-FGM平板受到均勻分佈負載之解析解 19 3.1.1 子問題(b)之位移解 19 3.1.2 子問題(c)之位移解 22 3.1.3 子問題(d)之位移解 24 3.1.4 利用疊加法求解彎矩大小 25 3.1.5 問題(a)之解析解 27 3.2 CCCC-FGM受到集中力之解析解 31 3.2.1 子問題(b)之位移解 31 3.2.2 子問題(c)之位移解 33 3.2.3 子問題(d)之位移解 33 3.2.4 利用疊加法求解彎矩大小 33 3.2.5 問題(a)之解析解 35 3.3 FGM平板解析解之退化問題 39 3.4 有限元素分析數值解適用性之探討 40 3.4. 1 FGM平板參數設定 40 3.4. 2 FGM平板之有限元素數值解 41 3.4. 3改變楊氏係數的比值 42 3.4. 4改變負載條件 44 第四章 SFSF-FGM平板受到均勻分佈負載之力學行為 62 4.1 SFSF-FGM平板受到均勻分佈負載之解析解 62 4.2 FGM平板理論與FGM樑之有限元素數值解比較 65 4.2. 1 FGM平板與FGM樑的參數設定 65 4.2. 2 FGM樑之有限元素數值解 66 4.2. 3 改變平板長寬比 66 第五章 結論 71 參考文獻 73

    [1] Y. D. Lee and F. Erdogan, “Residual/thermal stresses in FGM and laminated thermal barrier coatings”, International Journal of Fracture 69, 145-165, 1994.

    [2] 張燕玲與紀翔和,函數梯度材料之殘留應力分析,中國土木水利工程學刊,第十三卷,第一期,1-9,2001。

    [3] S. H. Chi and Y. L. Chung, “Mechanical behavior of functionally graded material plates under transverse load-PartⅠ: Analysis”, International Journal of Solids and Structure 43, 3657-3674, 2002.

    [4] S. H. Chi and Y. L. Chung, “Mechanical behavior of functionally graded material plates under transverse load-PartⅡ: Numerical results”, International Journal of Solids and Structure 43, 3675-3691, 2002.

    [5] 甘益萍與張燕玲,矩形功能梯度板受彎矩或沉陷時之分析,台灣科技大學營建工程研究所碩士論文,台灣,2005。

    [6] 楊幼安與張燕玲,一對邊為簡支端另一對邊為固定端之FGM連續板的力學分析,台灣科技大學營建工程研究所碩士論文,台灣,2010。

    [7] 杜鎮宇與張燕玲,兩對邊為簡支端另兩對邊為樑支FGM板受均勻分佈載重和溫度載重之力學行為,台灣科技大學營建工程研究所碩士論文,台灣,2013。

    [8] S. A. M. GhannadPour and M. M. Alinia, “Large deflection behavior of functionally graded plates under pressure loads”, Composite Structure 75, 61-71, 2006.

    [9] S. A. M. GhannadPour and M. M. Alinia, “Nonlinear analysis of pressure loaded FGM plates”, Composite Structure 88, 354-359, 2009.

    [10] B. V. Sankar, “An elasticity for functionally graded beam”, Composites Science and Technology 61, 689-696, 2001.

    [11] Z. Zheng and Y. Tao, “Analytical solution of a cantilever functionally graded beam”, Composites Science and Technology 67, 481-488, 2007.

    [12] M. Q. Wang and Y. H. Liu, “Analytical solution bi-material with graded intermediate layer”, Composite Structure 92, 2358-2368, 2010.

    [13] S. Timoshenko and S. Woinowsky-Krieger, Theory of Plates and Shells, Second Edition, McGraw Hill, New York, 1959.

    [14] E. H. Mansfield, The Bending and Stretching of Plates, Pergamon Press, New York, 1964.

    [15] E. Eduard, Thin Plates and Shells: Theory, Analysis, and Applications, Marcel Dekker, New York, 2001.

    下載圖示 校內:立即公開
    校外:2015-07-15公開
    QR CODE