工學院: 機械工程學研究所指導教授: 陳振山蔡明延Tsai, Ming-YenMing-YenTsai2017-03-132018-06-282017-03-132018-06-282016http://ntur.lib.ntu.edu.tw//handle/246246/278463考慮一圓形截面的直桿彎成圓環，讓兩端截面面對面無限靠近。本文將藉由理論模型與實驗操作探討當兩端截面相對夾一轉角差時的現象。我們以兩端截面轉角差及其所對應的扭矩為主要變數。數值模型方面採用elastica模型來模擬圓環並搭配shooting method求解。以半徑長度比為0.001的圓環進行數值模擬發現，當轉角差達到15.24 (rad)時，原來的圓形型態將跳躍成空間的兩點接觸。若繼續增加轉角差，圓環將從兩點接觸漸漸的轉變成三點接觸直到點線點接觸為止。 實驗方面，我們設計了一個簡單的裝置，控制兩端截面轉角差並量測扭矩。我們比較實驗結果與理論預測大致上吻合，尤其在分歧點時之跳躍行為。但在高轉角差時誤差加劇。估計這些實驗與理論之間的誤差主要產生於實驗安裝時的誤差及高轉角時試件產生塑性變形所導致。Consider an initially straight rod of circular cross section bent into a circular ring so that the cross sections of the two ends meet face to face. In this paper we study, both theoretically and experimentally, the behavior of the ring as the relative rotation between the two end cross sections increases quasi-statically. The variables of interest are the relative rotation angle and the corresponding twisting moment. In theoretical aspect the ring is modeled as elastica and its deformation is calculated by shooting method. It is found that a ring with dimensionless rod radius 0.001 jumps to a two-point self-contact deformation when the relative rotation angle increases to a critical value. As the rotation angle continues to increase, the deformation evolves smoothly to three-point contact and finally to point-line-point contact. In the experiment we build a simple device to control the relative rotation angle between the two end cross sections. Measumements of twisting moment and relative rotation angle are recorded and compared with theoretical prediction. Reasonable agreement between experiment and theory is observed. Installation misalighment and plastic deformation of the rod are the main causes of discrepancy between theory and experiment.1820102 bytesapplication/pdf論文公開時間: 2019/9/13論文使用權限: 同意有償授權(權利金給回饋本人)受扭矩圓環自我接觸shooting methodtwisted ringself-contactthesis10.6342/NTU201603327http://ntur.lib.ntu.edu.tw/bitstream/246246/278463/1/ntu-105-R03522524-1.pdf