臺灣博碩士論文加值系統

本論文主旨在研究輕軌車轉向架結構的疲勞壽命，探討在列車行駛中，因軌道不平整以及動態負荷情況下，評估轉向架結構之疲勞壽命。本研究運用動力學原理分析軌道車輛結構之機構運動，尤其是在列車行駛中，當軌道不平整時，車體結構受到往復外力影響，使得結構承受不等之應力大小。再者，本研究進一步利用有限元素法計算轉向架結構的應力分佈，然後依時間所產生的應力分佈情況，利用模態疊加法計算評估結構之疲勞壽命。

本研究將所推導出的輕軌車機構運動及其轉向架應力分佈與疲勞壽命評估法，運用相關軟體平台進行模擬與驗證。首先，在MSC.Patran環境下建立輕軌車轉向架之三維電腦模型，然後以有限元素軟體MSC.Nastran進行模態應力分析，產生各模態之頻率值，緊接著以ADAMS/rail分析軌道車輛結構在各種正弦曲線與隨機軌道不平整形態下的動態應力情況。這能暸解結構依軌道不整所產生之應力模態比例值，此模態比例值與模態頻率值將作為MSC.Fatigue分析結構疲勞壽命的主要依據。

本研究在車輛結構承受各種軌道不平整形態時，從分析過程中發現較規則性正弦曲線的車輛結構疲勞壽命較長，承受隨機不平整軌道的車輛結構疲勞壽命較短。而改善因隨機不平整軌道造成結構疲勞壽命縮短的方法，可以在結構上加強結構本身強度與使用較大極限抗拉強度的材料。這使得車輛結構疲勞壽命能達到符合所需求之壽命。

In this thesis, the structural fatigue of a LRV (Light Rail Vehicle) bogie will be analyzed based on CAE (Computer Aided Engineering) technology. Improving the bogie strength by using higher tensile strength material is also discussed. The analyzing procedures include:
(a) dynamic modeling of the LRV running with track irregularity;
(b) computing the variable loads applied on the bogie based on the track irregularity;
(c) evaluating the stress distribution due to the variable loads and modal analysis of the bogie by using of FEM (Finite Element Method);
(d) adopting the variable stress and modal superposition to estimate fatigue life of the bogie structure.
The algorithm and corresponding computer software used will be described briefly as follows. First, a 3D solid model of the bogie of LRV is to be generated by MSC.Patran��. Then, the 3D model is employed to generate nodes and meshes for FEM modal analysis by MSC.Nastran��. Also, the dynamic loading and variable stress of the bogie will be analyzed by modeling the LRV running on either sine curve or random irregularity track with the using of ADAMS/rail��. Finally, the modal proportion values and frequency of the stresses obtained prior are employed as input for bogie fatigue life analysis by MSC.Fatigue��.
The results of this study demonstrate that the irregularity of track is a sensitive criterion on bogie fatigue life. The bogie has longer life with LRV running on regular sine curve track and shorter life with running on random irregular track. Also, adopting high tensile strength material is a method for improving the fatigue life of bogie.

第一章 序論 1
1.1 前言 1
1.2 研究動機與目的 1
1.3 軟體簡介與研究方法 2
1.4 文獻回顧 3
第二章 相關理論介紹 7
2.1 有限元素法 7
2.1.1有限元素法之理論 7
2.1.2 平面結構特性 8
2.1.3四邊形平面元素 10
2.2 ADAMS/Flex柔性體理論 12
2.2.1模態疊加合成理論 13
2.2.2運動方程式 14
2.2.3運動微分方程式 15
第三章 整車模型之建立 18
3.1 台灣輕軌車基本架構 18
3.1.1 輕軌車整體尺寸 18
3.1.2 轉向架架構與懸吊系統參數 19
3.2 建模流程 22
3.3 轉向架柔性體模型建立 25
3.3.1 轉向架有限元素模型的建立 25
3.3.2 連接點 27
3.3.3 模態中性檔（Modal Neutral File） 29
3.4 ADAMS/Rail含柔性體整車模型 32
3.4.1生成柔性體轉向架 32
3.4.2 施加約束 33
3.4.3 柔性轉向架整車模型組裝 34
3.5 ADAMS/Rail不平整軌道模組 35
第四章 分析結果與討論 39
4.1 動力分析 39
4.2 疲勞壽命分析 41
4.2.1載荷歷程 41
4.2.2 材料性質 43
4.2.3 動力轉向架疲勞壽命 44
4.2.4 無動力轉向架疲勞壽命 52
4.3 結果探討與修正 67
第五章 結論 72
5.1 結果討論 72
5.2 未來展望 73
參考文獻 74

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