Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2549
標題: 使用實驗驗證之數值模型對承受軸向力薄圓柱殼挫屈行為之探討
Studies of Buckling Behavior of Thin-Walled Cylindrical Shell Under an Axial Load by an Experimentally Verified Numerical Model
作者: 史羅賓
Sliz, Robert
關鍵字: buckling
挫屈
thin-walled shell
imperfections
薄圓柱殼
出版社: 機械工程學系所
引用: [1] P. Seide, V. I. Weingarten, and E.J. Morgan, The development of design criteria for elastic stability of thin shell structures. Final Report: STL/TR-60-0000-19425, SpaceTechnology Laboratories, Inc, Los Angeles, CA, 1960. [2] V. Placak, J. Kuncl, Vypočet napjatosti skořepin. SNTL-nakladatelstvi technicke literatury, 1966. [3] P. Mandal, C.R. Calladine, Buckling of thin cylindrical shells under axial compression. International Jurnal of Solids and Structures 37, 4509-4525, 2000. [4] T. von Karman, L.G. Dunn, H. Tsien, The influence of curvature on the buckling characteristics of structures. Journal of the Aeronautical Sciences 7, 276-289, 1940. [5] T. von Karman, H. Tsien, The buckling of thin cylindrical shells under axial compression. Journal of the Aeronautical Sciences 8, 303-312, 1941. [6] W.T. Koiter, On the stability of elastic equilibrium. Ph.D. thesis, Delft, H J Paris, Amsterdam. English translation, Air Force Flight Dynamics Laboratory Technical Report, AFFDL-TR-70-25, Ohio, 1970. [7] D.O. Brush, B.O. Almorth, Buckling of Bars, Plates and Shells. Mc. Graw-Hill, New Yourk, 1975. [8] W. T. Koiter, The effect of axisymmetric imperfections on the buckling of cylindrical shells under axial compression. Kon. Neder. Acad. Wet. B. 66, 265-279, 1963. [9] J. Arbocz, C.D. Jr. Babcock, The effect of general imperfections on the buckling of cylindrical shells. J. Appl. Mech. 36 (1), 28-38, 1969. [10] W. Guggenberger, R. Greiner, J.M. Rotter, The behavior of locally-supported cylindrical shells: unstiffened shells. J. Construct. Steel Res. 56, 175-197, 2000. [11] J. Arbocz, The effect of imperfect boundary conditions on the collapse behaviour of anisotropic shells. Int. J. Solids Struct. 37, 6891-6915, 2000. [12] R. Greiner, P. Derler, Effect of imperfections on wind-loaded cylindrical shells. Thin-Walled Struct. 23, 271-282, 1995. [13] M. Cai, J.M.F.G. Holst, J.M. Rotter, Buckling strength of thin cylindrical shells under localised axial compression. In:Proceedings of 15th ASCE Engineering Mechanics Conference, June 2-5, Columbia University, New York, NY, 99-100, 2002. [14] W.T. Koiter, Elastic stability of solids and structures, A. M. A. van der Heijden, Editor, Cambridge University Press, 2009. [15] C. Hűhne, R. Rolfes, E. Breitbach, J. Tebme, Robust design of composite cylindrical shells under axial compression — Simulation and validation. Thin-Walled Structures 46, 947-962, 2008. [16] J.M.F.G. Holst, J.M. Rotter. Axially compressed cylindrical shells with local settlement. Thin-Walled Structures 43, 811-825, 2005. [17] V. Papadopoulos, P. Iglesis. The effect of non-uniformity of axial loading on the buckling behaviour of shells with random imperfections. International Journal of Solids and Structures 44, 6299-6317, 2007. [18] NASA SP-8007, Buckling of thin-walled circular cylinders, 1965. [19] M. Biagi, F. Del Medico. Reliability-based knockdown factors for composite cylindrical shells under axial compression. Thin-Walled Structures 46, 1351-1358, 2008. [20] European Cooperation for Space Standardization. Space engineering—structural factors of safety for spacecrafts and launchers. [Draft ECSS-E32-10A], 2007. [21] ARIANE 5 Program. Structural design, dimensioning & test specification. [A5-SG-1-X-10-ASAI], 2001. [22] J.W. Hutchinson, Knockdown factors for buckling of cylindrical and spherical shells subject to reduced biaxial membrane stress, International Journal of Solids and Structures 47, 1443-1448, 2010. [23] H. Wang, J.G.A. Croll, Optimisation of shell buckling using lower bound capacities, Thin-Walled Structures 46, 1011-1020, 2008. [24] Anon. Buckling of thin-walled circular cylinders, NASA SP-8007, 1968. [25] J.H. Argyris, M. Papadrakakis, G. Stefanou, Stochastic finite element analysis of shells. Comput. Methods Appl. Mech. Eng. 191, 41-42, 4781-4804, 2002. [26] C.Y. Song, Buckling of shells under non-uniform stress state, Ph.D. thesis, Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, 2002. [27] C.Y. Song, J.G. Teng, J.M. Rotter, Imperfection sensitivity of thin elastic cylindrical shells subject to partial axial compression, 2004
摘要: 於本文中首先介紹一個可靠且能準確預測承受軸向力薄圓柱殼挫屈的方法,並對其中實驗的配置與試件(specimen)的準備,包括利用三次元量測儀,量取薄殼試件表面的幾何上微小不平整的瑕疵,做詳細的討論。 其次利用不同複雜程度的有限元模型模擬實驗的配置,目的是嘗試獲得正確的有限元模型,使其預測的挫屈負荷與實驗值能夠一致。本文研究顯示,即使有限元模型中包括了圓柱殼表面的瑕疵以及偏心負載,但是若試件的夾持與支撐部分被當作剛體,則分析結果依然會高估了實驗的挫屈負荷值。對照之下,將夾持與支撐物模擬為彈性體,並考慮夾持與支撐間接觸邊界條件的有限元模型,獲得了最佳的結果。 本文中進一步利用上述經實驗驗證之最佳的有限元模型,探討影響含瑕疵之薄圓柱挫屈行為的因素,包括殼表面初始幾何瑕疵、負載的偏心量、偏心負載沿著圓周方向位置的改變、殼的細長程度等的效應,以及可以增加殼挫屈負載的方法。本文的研究結果顯示,對含表面不平整瑕疵的薄圓柱殼而言,偏心負載在圓周方向的位置對殼挫屈負載有極大的影響。此外也發現,結構最強與最弱之抗挫屈的偏心負載位置,和殼的表面最大徑向瑕疵位置有關。因此移動負載到適當的偏心位置,該結構可擁有最大的挫屈負荷。 最後,根據本文分析的結果發現,常被使用於設計薄圓柱殼挫屈負荷的縮減因子(knockdown factor)的值可以增加參數值αecc=0.207 的大小。 此參數值是依據分析本文中實驗試件,設想它們承受最佳和最差位置偏心負載兩種極端情形,所得到試件之挫屈負荷值為最小的散布範圍所決定的。對於可能因製造過程產生的不同瑕疵表面形狀,和不同的半徑厚度比的圓柱殼試件,這種挫屈負荷值散布情形值得進一步的探討,以取得最佳的αecc參數值。
A reliable and accurate method of the buckling prediction of thin-walled cylindrical shell under an axial load is presented first in this work. The experimental arrangement and specimens are discussed in detail, including the measurement of the geometric imperfections of the specimen's surface using a coordinate measuring machine. Different Finite Element (FE) models, in terms of complexity, are used to simulate the experiment arrangement in an attempt to get a good agreement with the experimental buckling loads. It has been demonstrated that FE models with simplified rigid support conditions overestimate the prediction of the experimental buckling load even though these models included the effects of the measured initial geometric imperfections and load eccentricity. By contrast, FE models with realistically modeled support conditions achieved the best result. The experimentally verified FE model was then employed to study the buckling behavior and the effect of measured initial geometric imperfections, load eccentricity size, load eccentricity position along the shell's circumferential direction, the potential effect of the shell's height, and the method of increasing the load-carrying capacity of the thin-walled shell. The presented work demonstrated the strong influence of the eccentric load position along the imperfect shell's circumferential direction on the buckling of the thin-walled shell. The strongest and the weakest eccentric loading location of the structure were found and their relations to the position of the maximal radial imperfection were indicated. The maximum load-carrying capacity of the shell was obtained by moving the applied load into the strongest eccentric load location of the structure. Finally, based on the result in this work, the knockdown factor used in the design of thin-walled shell could be increased by adding the parameter αecc=0.207. The value of αecc was defined based on the value of the minimal scatter in the buckling load between the cases under the action of optimized and weakest load for the studied specimens. This scatter in the buckling load should be investigated for more specimens with different imperfection shapes caused by different manufacturing processes, and also for different radius/thickness ratios to further optimize the value of αecc parameter.
URI: http://hdl.handle.net/11455/2549
其他識別: U0005-2801201111573100
文章連結: http://www.airitilibrary.com/Publication/alDetailedMesh1?DocID=U0005-2801201111573100
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