臺灣博碩士論文加值系統

近年來，能源危機且環保意識高漲，促使自行車在研發工作上更是精益求精，以滿足各方面的需求。使用者對於自行車性能的要求也越來越高，因此所需的自行車通常以車身輕、強度高、耐疲勞為主。有鑑於此，本文研究將探討鋁合金材料自行車車架的疲勞壽命，有助於車架的生產效益且獲得降低生產成本。
本論文將以鋁合金材料自行車車架作為主題，運用電腦繪圖軟體Solidworks繪製自行車車架模型，及使用疲勞分析軟件Msc.Fatigue，並採用歐盟EN14764城市與旅行用自行車安全要求和試驗方法，探討自行車車架受踩踏力疲勞壽命。由分析結果得知，下管管件在相同的厚度及相近的周長情況之下，以橫橢圓形的疲勞壽命為最佳，且發現五通BB寬度較短和管徑較大時，會有較高的壽命值。當座管形狀由圓形改橫橢圓形壽命明顯提高，改直橢圓形壽命明顯降低。最後，比較具均勻管件與非均勻管件厚度之車架疲勞壽命，非均勻管件厚度之車架不但提高疲勞壽命且可降低生產成本，非均勻管件厚度之車架可作為日後車架設計時之參考。

In recent years, the energy crisis and the environmental consciousness surges upward, urge the research and development work on bicycles are striving for perfection, to satisfy various aspects demands. The request on bicycle performance is getting higher and higher for users, so it needs light body, high intensity and endurance. According to these, this research will discuss fatigue life of Aluminum alloy material for bicycle frame and to contribute on production efficiency of the frame and can reduce the production cost.
The subject of this paper is about Aluminum alloy material for bicycle frame, not only using computer graphics software Solidworks to draw out bicycle frame models, and using fatigue analysis software Msc.Fatigue to analysis fatigue life of bicycle frame pedaling but also according to the EN14764 city and trekking by bicycle safety requirements and test method. By analysis results, for all the seven types of lower tube, the fatigue life for the horizontal oval is the longst and it was also noted of button bracket width is shorter and diameter is larger possess the highest life. When the shape of the seat tube change from circle to horizontal oval, the fatigue life distinct enhancement; when changing to vertical oval, the fatigue life reduces obviously. Finally, the frame fatigue life of uniform tube thickness compare with asymmetrical tube thickness of the frame, the asymmetrical tube thickness of the frame not only enhances the fatigue life but also can reduce the production cost. We may take it the frame designs when reference in the future.

誌謝............... I
摘要............... II
Abstract........... III
目錄............... IV
圖目錄............. VII
表目錄............. IX
第 一 章 緒論............. 1
1.1 簡介.................. 1
1.2 文獻回顧.............. 1
1.3 研究動機及方法...........4
1.4 研究架構................ 4
第 二 章 相關理論介紹.............6
2.1有限元素法之理論基礎.............6
2.2疲勞壽命理論.............10
2.2.1應力-壽命曲線(S-N曲線) 12
2.2.2應力-壽命曲線(S-N曲線)數學表達式.............13
2.2.3平均應力對疲勞強度的影響.............14
2.2.4疲勞負載型式.............17
2.3等效應力(von Mises Stress).............19
第 三 章 自行車車架模型建立與踩踏力疲勞分析.............21
3.1前言.............21
3.2自行車車架模型建立.............26
3.3自行車車架受踩踏力疲勞試驗.............28
3.3.1 網格設定.............29
3.3.2 邊界條件設定.............30
3.3.3 疲勞分析.............31
第 四 章 踩踏力疲勞分析結果與討論.............34
4.1 前言.............34
4.2不同下管管形之車架疲勞壽命分析.............34
4.3不同五通BB寬度之車架疲勞壽命分析.............45
4.4不同五通BB管徑之車架疲勞壽命分析.............46
4.5不同座管之車架疲勞壽命分析.............48
4.6具均勻管件與非均勻管件厚度之車架疲勞壽命分析..........49
第 五 章 結論與未來展望.............52
5.1 結論.............52
5.2 未來展望.............53
參考文獻.............54
附錄.............57

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