(3.238.7.202) 您好!臺灣時間:2021/02/26 15:16
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果

詳目顯示:::

我願授權國圖
: 
twitterline
研究生:鍾坤林
研究生(外文):Kun-Lin Chung
論文名稱:結構破壞修補之裂紋強度因子分析
論文名稱(外文):Analysis for Stress Intensity Factor of Patch Repaired Structures
指導教授:夏育群夏育群引用關係
指導教授(外文):Yui-Chuin Shiah
學位類別:碩士
校院名稱:逢甲大學
系所名稱:航太與系統工程所
學門:工程學門
學類:機械工程學類
論文種類:學術論文
論文出版年:2011
畢業學年度:99
語文別:中文
論文頁數:91
中文關鍵詞:有限元素法應力強度因子裂紋修補
外文關鍵詞:Patch Repair.Finite Element MethodStress Intensity Factor
相關次數:
  • 被引用被引用:2
  • 點閱點閱:289
  • 評分評分:系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔
  • 下載下載:62
  • 收藏至我的研究室書目清單書目收藏:0
當金屬結構上發生裂紋,若處理不好,可能將導致意想不到的後果;本文主要為運用ANSYS軟體的KCALC指令求解及分析,如裂紋發生於厚度僅為0.08 inches的等向性金屬薄板(AL2024-T3),當裂紋形狀為曲線型(Smile)、斜線型(Oblique)與扭結型(Kinked)時之應力強度因子(Stress Intensity Factor),並探討上述各型裂紋薄板以厚度為0.09 inches、同材料性質之加強片進行貼補修理後,其應力強度因子之改變。
由於受損金屬板與加強片的厚度都非常薄,相較於受損金屬板及加強片面積的尺寸( 50x50 inches & Radius=1.02 ~ 11.02 inches)與受損金屬板上裂紋的長度(1 inch)相差很大,為求精確的貼補模型及避免過多的變因,先以2D裂紋模型建模分析,再以原2D裂紋模型的網格(Mesh)規劃推展至3D裂紋模型,且皆與文獻之應力強度因子解析解相比,以確認2D及3D裂紋模型建立無誤,最後將3D模型擴展至裂紋的貼補模型;為簡化模型及避免平面外剪斷模式(Mode III, KIII)的干擾,以求得準確的應力強度因子變化,故貼補模型假設為不經Damage Free的處理程序(不先將裂紋處之面積挖除,而直接在裂紋的雙面加以貼補加強片) ,並忽略當進行貼補修理時之鉚釘與膠層的影響。
本文運用ANSYS軟體中的KCALC指令,此指令乃參考線性彈力破壞力學(Linear Elastic Fracture Mechanics)的裂紋應力強度因子計算理論,利用裂紋附近節點的位移,先求出其應力強度因子後,再以位移內差法推算出裂紋尖端的應力強度因子;以此指令求解2D裂紋模型的應力強度因子並與解析解比較後,吾人可知2D分析之精準度是可信賴的,然而在求解3D薄板裂紋模型方面則會有浦松比(Pission ratio)所造成的差異,因其缺乏足夠的文獻資料比對,本論文僅將2D與3D的分析結果相比較,其結果的差異度非常微小,由此驗證3D分析之可靠度為可接受的。
由本論文之裂紋直接貼補分析,可知在航空器蒙皮結構修補上,以貼補加強片方式可大幅的降低裂紋尖端的應力強度因子,但在加強片尺寸大小的改變,分析結果顯示其應力強度因子的改變差異並不大,表示對降低應力強度因子並無太大的影響。
Any crack present on a metal structure may lead to unwanted result if not treated properly. This research uses KCALC instruction of ANSYS software to resolve and analyze structural crack problems. When cracks occur on an isotropic thin metal plate (AL2024-T3) of 0.08 inches thick, with the shapes of cracks in Smile, Oblique or Kinked form, this research tries to examine the stress intensity factors of the various forms. In comparison, the thickness of the plate is increased to 0.09 inches or patch doublers of the same material are attached to the crack area, and then the variations of the corresponding stress intensity factors are recorded.
The thicknesses of the damaged metal plate and doublers are relatively small when compared with the sizes of the plate and the doublers (50x50 inches & Radius=1.02 ~ 11.02 inches) or the length of the crack on the plate (1 inch). For more accurate patch repair and less variants involved, 2D model is established first and based on the mesh of which, 3D crack model is established. To ensure the accuracy of the established models, the stress intensity factors of the 2D and 3D crack models are compared with the documented figures. Finally, patch doubler model is established base on the 3D model. For more accurate stress intensity factors, damage free process is not performed on the patch doubler model (no cut-out of the crack area, and instead, two-side doublers are directly attached to the crack area) so as to simplify the modeling process and avoid Mode III ( KIII) interruptions. Moreover, rivet and adhesive factors are also excluded from this study.

In this study, KCALC instruction of ANSYS software is used, which applies the crack stress intensity factor calculation of the Linear Elastic Fracture Mechanics. Based on the displacement of the nodes in the vicinity of the crack, the stress intensity factor is first derived, followed by stress intensity factors at the crack ends by means of displacement interpolation method. By using the KCALC instruction, the stress intensity factor of the 2D crack model is achieved and resolved. When compared with the documented resolution, its accuracy has proved to be reliable. However, Pission ratio may factor in the 3D thin plate crack model, resulting in errors. Unfortunately, the documented data available for comparison of the 3D model is limited. So, this research only analyzes and compares the 2D and 3D results. As the difference examined is little, 3D model analysis can be verified to be reliable.
Through the patch doubler repair analysis, it is known that the attached doubler may reduce the stress intensity factor of the crack ends to a great extent. With the dimension of the doubler adjusted, the analysis shows that the change of the stress intensity factors is limited. In other words, the size of the doubler has little influence on reducing stress intensity factors.
致謝 iii
摘要 iv
Abstract vi
目錄 viii
圖目錄 x
表目錄 xvi
第一章 概論 1
1.1 引言 1
1.2 研究動機與目的 2
1.3 研究方法與流程 3
第二章 基本理論文與獻回顧 7
2.1 有限元素法簡介 7
2.2 破壞力學簡介 10
2.3 能量釋放率與應力強度因子 12
2.4 曲線型、斜線性與扭結型裂紋 14
2.5 航空器結構蒙皮的檢查與修護 16
第三章 CAE模型建立 24
3.1 CAE軟體簡介 24
3.2 ANSYS之裂紋求解 28
3.3 元素及材料定義 31
3.4 基本模型假設 32
3.5 ANSYS軟體之分析模型建立與求解 34
第四章 模擬結果與分析 51
4.1 2D與3D的模型建立與求解 51
4.2 曲線型、斜線型與紐節型裂紋 52
4.3 結構破壞之裂紋強度因子分析 53
第五章 結果討論與未來展望 84
5.1 模型建立與網格規劃 84
5.2 ANSYS指令之使用 85
5.3 貼補模型分析與未來展望 86
參考文獻 88
附錄 92
【1】 Turner, M. J., Clough, R. W., Martin, H. C., and Topp, L. J., “Stifness and Deflection Analysis of Complex Structures”, Journal of Aeronautical Sciences, 23, 805-824, 1956.
【2】 曾昭仁 譯,“應用有限元素分析”,科技圖書股份有限公司,1987。
【3】 王勗成與邵敏 編著,“有限元素法之基本原理與數值方法”,亞東書局印行,1990。
【4】 黃錦煌與吳佐群 編著,“有限元素分析大師”,高立圖書有限公司,2004。
【5】 Rao, S. S., 陳昭昌編譯, “有限元素法-工程上之應用”,The Finite Element Method in Engineering,復文書局,1989 年。
【6】 李輝煌,“ANSYS 工程分析基礎與觀念”,國立圖書有有限公司,2005年。
【7】 Bathe, K. J. , “Finite Element Procedures”, Prentice-Hall, Inc., New Jersey, 1996.
【8】 Becker, E. B., Carey, G. F., and Oden, J. T., “Finite Element: An Lnteroduction Volume I”, Prentice-Hall, Inc., New Jersey, 1981.
【9】小林英男 著,劉松伯博士 譯,“破壞力學(增訂版)”,龍璟文化,民國93年。
【10】Griffith, A. A. ,”The Phenomena of Rupture and Flow in Sloids,”, Phil. Trans. Roy. Soe. , A221, pp.163 (1921).
【11】Irwin, G. R. , “ Analysis of Stress and Strain Near the End of Crack Traversing a Plate”, J. Appel Mechs.,Vol.24, pp.361-364 (1957).
【12】Irwin, G. R., “Fracture, Encyclopedic of Physicists”, Fluge, Springer. Verlug, pp.551-589 (1958).
【13】Yui-Chuin Shiah, “Fracture of an Infinitely Large Elastic Plate Containing a Curved Crack”, Iowa State University, Ames, Iowa, 1996.
【14】中國航空研究院,“應力強度因子手冊[M] ”,北京,科學出版社,1993。
【15】N.M.I. HAMMOUDA, A.S. FAYED AND H.E.M. SALLAM, “Stress intensity factor of a central slant with frictional surface in plates with biaxial loading.” ,International Journal of Fracture 129, 141-148,2004.
【16】M.A. Meggiolaro, “Stress intensity factor equation for branched crack growth”, Engineering Fracture Mechanics 72, pp.2647-2671 (2005)
【17】Eng. Amr Shehata Mohammad Fryed, “MIX MODE CRACK TIP DEFORMATION DUE TO MULTI-AXIAL CYCLIC LOADING”, Ass. Lecturer, Materials Engineering Dept. Zagazing University.(2002)
【18】The Boeing Company, ” Structural Repair Manual ”, USA, (2010).
【19】The AIRBUS Company, ” Structural Repair Manual”, France, (2010).
【20】陳精一,“ANSYS 7.0電腦輔助工程實務分析” ,全華圖書,2008。
【21】于骁中、谯常析,“岩石和混泥土斷裂力學[M]” ,長沙,中南工業大學出版社,1991。
【22】ANSYS,Inc. “Release 11.0 Online Documentation for ANSYS“ ,2007.
【23】MatWeb, LLC.,” http://www.matweb.com/index.aspx “, 2020 Kraft Drive, Suite 3000 Blacksbrug, VA 24060.
【24】賴峯民 薛鈞謄 陳裕偉 曹季涵,“不同裂縫型態與修補試片之複合材料層板的應力強度因子” ,科學與工程技術期刊, 第六卷,第一期,民國九十九年。
【25】Moes, Dolbow, and Belytschko, “A finite element method for crack growth without remeshing,” International Journal For Numerical Methods In Engineering, Vol.46, pp.131-150, 1999.
【26】吳昱奇,“裂紋填充物對應力強度因子之影響”,成大土木工程研究所,碩士論文,民國九十一年。
【27】李臻,“經常服役的鋼結構疲勞壽命估算”,機械強度,西安石油大學機械工程學院,西安71006 (2008)。
【28】邢志賺高庆吉党长河,“飛機蒙皮檢查機器人系統研究”,機器人ROBOT,文章編號:1002-0446(2007)05-0474-05,第29卷第5期2007年,天津300071
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top
系統版面圖檔 系統版面圖檔