陳振山臺灣大學：機械工程學研究所李志章Li, Chih-ChangChih-ChangLi2007-11-282018-06-282007-11-282018-06-282007http://ntur.lib.ntu.edu.tw//handle/246246/61435本文以理論分析預測拱形樑於端點分別受到靜態與動態的力矩作用下，發生折斷式挫曲所需的臨界力矩，同時以數值方法模擬拱形樑受到步階形式力矩作用時的動態反應，並以實驗量測來驗証理論所求出的結果。在實驗量測方面，我們首先量測拱形樑於一端及兩端受到緩慢增加的力矩作用時，拱形樑中點高度的變化，之後我們量測拱形樑中點受到敲擊時振幅衰減的比例，用來估計拱形樑的阻尼係數，以及量測拱形樑於受力及未受力的情況下的自然頻率，最後我們量測拱形樑於一端及兩端受到步階形式力矩作用下發生折斷式挫曲時，中點高度隨時間變化的行為，並將實驗量得的數據與代入估計阻尼係數作數值模擬所得到的結果相互對照。In this paper we investigate, both numerically and experimentally, both the static and dynamic case, the end couple is applied in the form of a step function with infinite duration. Attention is focused on the prediction of the snap-through buckling loads, both static and dynamic. The relations between the critical load with different initial heights are presented. In the experiment we examine the arch when one end and both ends are affected by moment increased slowly, the change of the height of mid point of the arch, later we amount examined the proportion that the amplitude decayed when the arch mid point was beaten, used for estimating the arch damping coefficient, and quantity examine the arch on strength and receive natural frequency of situation of strength, we amount finally examine the arch happen person who break at the song of frustrating until one end and both ends affect by steps form moment of the step, the behavior that the mid point highly changes over time, and the data won of the testing amount, with taking the place of and entering estimating that contrast each other in result that will be received of simulation of counting value of damping coefficient.第一章 導論............................................1 第二章 實驗設備........................................3 第三章 運動方程式......................................5 3.1 一端受力矩時之運動方程式........................5 3.2 兩端受力矩時之運動方程式........................7 3.3 討論............................................8 第四章 靜態分析與動態分析..............................9 4.1 靜態分析........................................9 4.1.1 一端受力矩時之靜態分析......................9 4.1.2 兩端受力矩時之靜態分析.....................10 4.1.2.1 對稱解..................................10 4.1.2.2 非對稱解................................11 4.1.3 討論........................................12 4.2 動態分析.......................................13 4.2.1 一端受力矩時之動態分析.......................13 4.2.2 兩端受力矩時之動態分析.......................14 4.3 收斂性測試.....................................14 4.3.1 靜態解的收斂性.................................14 4.3.2 動態解的收斂性.................................14 第五章 預測折斷式挫曲之臨界力矩.......................16 5.1 一端受力矩時之折斷式挫曲臨界力矩...............16 5.2 兩端受力矩時之折斷式挫曲臨界力矩...............17 5.3 討論...........................................18 第六章 自然頻率與等效阻尼.............................19 6.1 系統的自然頻率.................................19 6.2 等效阻尼的估計.................................21 第七章 實驗量測與理論對照.............................23 7.1 拱形樑自然頻率量測.............................23 7.1.1 拱形樑一端受力矩時的自然頻率量測...............23 7.1.2 拱形樑兩端受力矩時的自然頻率量測...............24 7.2 拱形樑靜態變形量測.............................24 7.2.1 拱形樑於一端受力矩時的靜態變形量測.............24 7.2.2 拱形樑於兩端受力矩時的靜態變形量測.............25 7.3 拱形樑動態變形量測.............................25 7.3.1 拱形樑於一端受力矩時的動態變形量測.............25 7.3.2 拱形樑於兩端受力矩時的動態變形量測.............27 第八章 結論...........................................28 參考文獻................................................30 附圖目錄................................................311169315 bytesapplication/pdfen-US拱形樑archthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/61435/1/ntu-96-R94522522-1.pdf