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研究生： 廖信智
Liao, Shin-chin
論文名稱： 尖銳凹槽薄壁管在循環彎曲負載下黏塑性皺曲行為之研究
Viscoplastic Buckling of Sharp-Notched Thin-Walled Tubes under Cyclic Bending
指導教授： 潘文峰
Pan, Wen-fung
學位類別： 碩士
Master
系所名稱： 工學院 - 工程科學系
Department of Engineering Science
論文出版年： 2009
畢業學年度： 97
語文別： 中文
論文頁數： 71
中文關鍵詞： 循環彎曲 、循環硬化 、橢圓化
外文關鍵詞： COMA, buckling
相關次數： 點閱：93  下載：2 
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    • 本文主要探討具尖銳凹槽深度0.4 mm的SUS304不銹鋼管做對稱循環彎曲負載實驗，以探討其黏塑性力學行為與黏塑性皺曲損壞。實驗係透過彎管試驗機與曲度-橢圓化量測器來進行不同彎曲曲度速率控制的實驗與量測。從彎矩－曲度曲線圖中顯示出，在不同控制曲度速率做循環彎曲負載時，圓管皆有發生循環硬化的現象，且隨著循環圈數的增加，曲線迴圈漸漸趨於穩定的狀態；至於橢圓化－曲度的曲線圖則發現，橢圓化值會隨著循環彎曲的圈數增加而呈棘齒狀的增加，當橢圓化值達到某一臨界值時，圓管即發生皺曲損壞。此外，由實驗曲度－循環圈數的關係圖可看出，控制的曲度速率越大時，產生皺曲損壞所需循環圈數就越少。若將上述的實驗數據置於雙對數座標中，可發現三種不同彎曲曲度速率下的實驗試件呈現三條不平行且間距不相等的直線。最後，本文參考Shaw and Kyriakides【2】與Pan and Her【8】文獻中所提出的理論方程式後，提出一個可以描述具尖銳凹槽深度薄壁管在不同控制曲度速率循環彎曲負載時，控制曲度與循環彎曲至皺曲圈數關係的理論方程式。本文將該方程式的分析結果與實驗數據加以比較後發現，理論分析能符合實驗結果。

    This thesis investigates the viscoplastic behavior and viscoplastic buckling of SUS 304 stainless steel tubes with a 0.4 mm sharp-notched depth subjected to symmetric cycling bending. The tube bending machine and curvature-ovalization measurement apparatus were used to control the different curvature-rates and measure the related data. It can be observed that the experimental moment-curvatrue curves exhibit cyclic hardening for all tubes under cycling bending with different curvature- rates. The loops become steady after a few cycles. As for the ovalization-curvature curve, the ovalization of the tube cross-section increases in a ratcheting manner with the number of cycles. The tube buckles when the ovalization reaches a critical value. In addition, from the curvature-number of cycles to produce buckling curve, the larger curvature-rate leads to smaller amount of the number of cycles to produce buckling. If the aforementioned experimental data indicate in the log-log scale, three non-parallel straight lines for three different curvature-rates are found. Finally, by referencing the theoretical formulations propossed by Shaw and Kyriakides [2] and Pan and Her [8], a theoretical equation was proposed to simulate the relationship between the controlled curvature and the number of cycles to produce buckling for different curvature-rates of notched circular tubes under cyclic bending. By comparing the experimental data and theoretical simulation, good agreement between the experimental and theoretical results has been achieved.

    摘 要 ------------------------------------------------------------------------- Ⅰ Abstract ------------------------------------------------------------------------- Ⅱ 誌 謝 ------------------------------------------------------------------------- Ⅲ 目 錄 ------------------------------------------------------------------------- Ⅳ 表 目 錄 ------------------------------------------------------------------------- Ⅵ 圖 目 錄 ------------------------------------------------------------------------- Ⅶ 符號說明 ------------------------------------------------------------------------- X 第一章 緒論---------------------------------------------------------- 1 1-1 研究動機------------------------------------------------------- 1 1-2 文獻回顧------------------------------------------------------- 2 1-3 研究目的------------------------------------------------------- 9 第二章 實驗設備---------------------------------------------------- 11 2-1 彎管實驗機本體---------------------------------------------- 11 2-2 油壓伺服控制系統------------------------------------------- 13 2-3 電腦控制系統------------------------------------------------- 15 2-4 檢測儀器------------------------------------------------------- 16 2-5 整體設備作動原理------------------------------------------- 19 2-6 整體效能------------------------------------------------------- 20 第三章 實驗方法---------------------------------------------------- 31 3-1 實驗方式與原理---------------------------------------------- 31 3-2 實驗材料與規格---------------------------------------------- 32 3-3 實驗程序------------------------------------------------------- 33 3-4 資料收集與整理---------------------------------------------- 34 3-5 注意事項------------------------------------------------------- 36 第四章 實驗結果與理論分析------------------------------------- 41 4-1 力學行為之實驗結果---------------------------------------- 41 4-1-1 彎矩與曲度關係----------------------------------------- 41 4-1-2 曲度速率橢圓化關係----------------------------------- 42 4-1-3 曲度與皺曲損壞所需圈數關係----------------------- 43 4-2 理論分析------------------------------------------------------- 43 第五章 結論---------------------------------------------------------- 55 參考文獻 ------------------------------------------------------------------------- 57 表目錄 表3-1 不銹鋼管的尺寸表----------------------------------------------- 38 表3-2 SUS 304無縫不銹鋼管化學元素表--------------------------- 38 圖目錄 圖2-1 彎管實驗機本體的示意圖-------------------------------------- 22 圖2-2 彎管實驗機實體照片-------------------------------------------- 22 圖2-3 不同尺寸的實心桿照片----------------------------------------- 23 圖2-4 實心桿細部車削照片-------------------------------------------- 23 圖2-5 油壓動力設備照片----------------------------------------------- 24 圖2-6 油壓伺服控制系統圖-------------------------------------------- 24 圖2-7 上油壓缸照片----------------------------------------------------- 25 圖2-8 電腦監控系統照片----------------------------------------------- 25 圖2-9 控制流程圖-------------------------------------------------------- 26 圖2-10 力檢測器照片----------------------------------------------------- 26 圖2-11 COMA實體照片------------------------------------------------- 27 圖2-12 COMA立體示意圖---------------------------------------------- 27 圖2-13 COMA側視圖---------------------------------------------------- 28 圖2-14 曲度量測示意圖-------------------------------------------------- 28 圖2-15 薄壁管正向彎曲負載時的油路圖----------------------------- 29 圖2-16 薄壁管反向彎曲負載時的油路圖----------------------------- 29 圖2-17 彎管實驗機之鏈條拉力轉換成彎曲力矩之機構示意圖-- 30 圖2-18 薄壁管試件與實心桿之安裝狀態示意圖-------------------- 30 圖3-1 尖銳凹槽0.4mm的不銹鋼薄壁圓管圖---------------------- 38 圖3-2 尖銳凹槽0.4mm的SUS304不銹鋼薄壁圓管照片-------- 39 圖3-3 彎管實驗流程圖-------------------------------------------------- 39 圖3-4 實驗用冷卻設備-------------------------------------------------- 40 圖3-5 斷面橢圓化示意圖----------------------------------------------- 40 圖4-1 曲度速率0.0035m-1s-1時的SUS304不銹鋼管之彎矩-曲 度圖----------------------------------------------------------------- 47 圖4-2 曲度速率0.035m-1s-1時的SUS304不銹鋼管之彎矩-曲度 圖-------------------------------------------------------------------- 47 圖4-3 曲度速率0.35m-1s-1時的SUS304不銹鋼管之彎矩-曲度 圖-------------------------------------------------------------------- 48 圖4-4 三種不同曲度速率SUS304不銹鋼管穩定狀態之彎矩- 曲度圖-------------------------------------------------------------- 48 圖4-5 曲度速率0.0035m-1s-1時的SUS304不銹鋼管之橢圓化- 曲度圖-------------------------------------------------------------- 49 圖4-6 曲度速率0.035m-1s-1時的SUS304不銹鋼管之橢圓化- 曲度圖-------------------------------------------------------------- 49 圖4-7 曲度速率0.35m-1s-1時的SUS304不銹鋼管之橢圓化-曲 度圖----------------------------------------------------------------- 50 圖4-8 曲度控制為0.1m-1時，不同彎曲曲度速率下SUS304不 銹鋼在彎曲循環負載下之循環圈數與最大±κ時橢圓化 的變化量關係圖-------------------------------------------------- 50 圖4-9 曲度速率控制為0.0035m-1s-1時，不同彎曲曲度下SUS 304不銹鋼在循環彎曲負載下之循環圈數與最大±κ時 橢圓化的變化量關係圖----------------------------------------- 51 圖4-10 SUS304不銹鋼在彎曲循環負載下之皺曲發生所需圈數 與曲度的關係圖-------------------------------------------------- 52 圖4-11 SUS304不銹鋼在彎曲循環負載下之皺曲發生所需圈數 與曲度的雙對數座標關係圖----------------------------------- 53 圖4-12 SUS304不銹鋼在彎曲循環負載下理論與實驗值之皺曲 行為發生所需圈數與曲度的雙對數座標關係圖----------- 54

    參考文獻

    1. Shaw, P. K. and Kyriakides, S., 1985, “ Inelastic Analysis of Thin-Walled Tubes under Cyclic Bending, ” International Journal of Solids and Structures, Vol. 21, pp. 1073-1100.

    2. Kyriakides, S. and Shaw, P. K., 1987, “ Inelastic Buckling of Tubes under Cyclic Bending, ” Journal of Pressure Vessel Technology, Vol. 109, pp.169-178.

    3. Corona, E. and Kyriakides, S., 1988, “ On the Collapse of Inelastic Tubes under Combined Bending and Pressure, ” International Journal of Solids and Structures, Vol. 24, pp. 505-535.

    4. Corona, E. and Kyriakides, S., 1991, “ An Experimental Investigation Degradation and Buckling of Circular Tubes under Cyclic Bending and External Pressure , ” Thin-Walled Structures, Vol. 12, pp. 229-263.

    5. Ju, G. T. and Kyriakides, S., 1992, “ Bifurcation Buckling Versus Limit Load Instabilities of Elastic-Plastic Tubes under Bending and External Pressure, ” Journal of Offshore Mechanics and Arctic Engineering, Vol. 113, pp. 43-52.

    6. Vaze, P. and Corona, E., 1996, “ Degradation and Collapse of Tube under Cyclic Bending, ” Thin Wall Structures, Vol. 31, pp. 325-341.

    7. Pan, W. F., Wang, T. R. and Hsu, C. M., 1998, “ A Curvature-Ovalization Measurement Apparatus for Circular Tubes under Cyclic Bending, ” Experimental Mechanics, Vol. 38, No.2, pp. 99-102.

    8. Pan, W. F., Her and Y. S., 1998, “ Viscoplastic Collapse of Thin-Walled Tubes under Cyclic Bending, ” Journal of Engineering Materials and Technology, Vol. 120, pp. 001-004.

    9. Pan, W. F. and Fan, C. H., 1998, “ An Experimental Study on the Effect of Curvature-Rate at Preloading Stage on Subsequent Creep or Relaxation of Thin-Walled Tubes under Pure Bending, ” JSME International Journal, Series A, Vol. 41, No.4, pp. 525-531.

    10. Lee, K. L., Pan, W. F. and Kuo, J. N., 2001, “ The Influence of the Diameter-to-Thickness Ratio on the Stability of Circular Tubes under Cyclic Bending, ” International Journal of Solids and Structures, Vol.38, pp. 2401-2413.

    11. Lee, K. L., and Pan, W. F., 2001, “ Viscoplastic Collapse of Titanium Alloy Tube under Cyclic Bending, ” Structural Engineering and Mechanics – an International Journal, Vol. 11, No.3, pp. 315-324.

    12. Lee, K. L. and Pan, W. F., 2002, “ Pure Bending Creep of SUS 304 Stainless Steel Tuber, ” Steel and Composite Structures - an International Journal, Vol. 2, No.6, pp. 461-474.

    13. Lee, K. L., Shie, R. F. and Chang, K. H., 2005, “ Experimental and Theoretical Investigation of the Response and Collapse of 316L Stainless Steel Tubes Subjected to Cyclic Bending, ” JSME International Journal, Series A , Vol. 48, No.3, pp. 155-162 .

    14.Chang, K.H., and Pan, W.F., 2009, “Buckling life estimation of circular tubes under cyclic bending,”International Journal of Solids and Structures Vol.46,pp. 254-270.

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