本研究之主要目的是將電動摩托車之前叉結構進行輕量化設計，並分析輕量化結構之力學行為。首先，將電動摩托車前叉結構之基本剛性強度及疲勞耐久性能數據統整後，針對前叉結構應力較弱之部件進行補強。待補強完成後，為了有效率的進行前叉結構之輕量化，因此使用拓樸分析進行結構最佳化設計，再依據拓樸分析結果重新進行前叉結構之設計。重新設計之前叉結構依序需通過標準工況分析、 剛性分析、整車強度分析、及疲勞耐久分析之驗證。
標準工況的驗證條件為：重新設計之前叉結構其部件之最大應力值不得超過給定之目標應力上限。剛性分析的驗證條件為：重新設計之前叉結構其剛性值需達原前叉剛性90%以上視為通過驗證。整車強度分析之驗證條件為：重新設計之前叉結構之強度表現優於原前叉視為通過驗證。疲勞耐久分析之驗證條件為：重新設計之前叉結構之疲勞第一損傷值小於原前叉視為通過驗證。
前叉結構經輕量化過後，總重量減少19.8%，其中管件及鈑件部分減少19.1%；三角台部分減少23.9%。
(1) F1管件底部擴管並增加管厚補強；(2) F2管件改變其幾何形式，轉彎處以更平滑方式連接；(3) F3及F4鈑件之鈑厚增加；(4) 三角台部分改為類桁架式結構。經過以上說明之補強方式後，輕量化前叉於標準工況分析、 剛性分析、整車強度分析、及疲勞耐久分析皆已通過驗證，即表示輕量化前叉不僅完成減重效益，其基本剛性強度及疲勞耐久仍維持一定程度甚至優於原始前叉。

The primary aim of this research is to design a lightweight structure for the front fork of an electric motorcycle and analyze its mechanical behavior. Firstly, the basic stiffness, strength, and fatigue durability data of the front fork structure are consolidated. Then, the weaker components of the front fork structure are reinforced. After the reinforcement is completed, in order to efficiently proceed with the lightweight design of the front fork structure, topology analysis is employed for structural optimization.. Based on the results of the topology analysis, the front fork structure is redesigned. The redesigned front fork structure needs to pass validation through standard operating conditions analysis, stiffness analysis, vehicle strength analysis, and fatigue durability analysis.
The validation criteria for standard operating conditions require that the maximum stress values of the components in the redesigned front fork structure do not exceed the given target stress limit. For stiffness analysis, the redesigned front fork structure must achieve a stiffness value of at least 90% of the original front fork's stiffness to pass the validation. In vehicle strength analysis, the strength performance of the redesigned front fork structure should be superior to that of the original front fork. The fatigue durability analysis validates the redesigned front fork structure if its fatigue first damage value is lower than that of the original front fork.
After the lightweighting process, the total weight of the front fork is reduced by 19.8%, with the tubing and sheet metal parts experiencing a reduction of 19.1%, and the triple clamp a reduction of 23.9%.
The reinforcement methods involved in the process include: (1) expanding the bottom of the F1 tubing and adding thickness for reinforcement, (2) altering the geometry of the F2 tubing and creating smoother connections at bends, (3) increasing the sheet metal thickness of the F3 and F4 components, and (4) transforming the triple clamp into a truss-like structure. After implementing these reinforcement techniques, the lightweight front fork successfully passes validation in terms of standard operating conditions analysis, stiffness analysis, vehicle strength analysis, and fatigue durability analysis. This indicates that the lightweight front fork not only achieves weight reduction but also maintains a certain level of basic stiffness, strength, and fatigue durability, and in some cases, even outperforms the original front fork.

[1] 陳明發,「機車車架之有限元素應力分析」,國立成功大學機械工程研究所碩士論文,1989
[2] 江銘傑,「機車鋁合金車架之應力分析與結構最佳化」,國立交通大學機械工程研究碩士論文, 2006
[3] 卓進興, 「機車車體結構分析與最佳化設計之研究」,大葉大學機械工程研究所碩士論文, 2003
[4] 林晉生,「應用拓樸最佳化於結構設計之研究」,淡江大學航空太空工程學系碩士論文, 2002
[5] 張祥唐,「拓樸最佳化設計方法在車架設計之研究」,國立成功大學機械工程研究所碩士論文, 2000
[6] 許萬賞,「自行車車架幾何結構最佳化分析」,國立高雄應用科技大學模具工程系碩士論文, 2010
[7] 陳建國,「有限元素法應用於電動機車車架之結構分析與模式建立」,國立成功大學機械工程研究所碩士論文,1999
[8] 顏健軒,「電動機車車架設計與疲勞分析」,國立臺北科技大學製造科技研究所,2011
[9] 郭昱鼎,「電動摩托車車架力學行為及疲勞損傷分析」,國立臺灣科技大學營建工程系碩士論文, 2022
[10] Ahmad, M.I. and P. Dorlikar. Design Study of an Electric Motorcycle Chassis Obtained using Topology Optimization. in IOP Conference Series: Materials Science and Engineering. 2021. IOP Publishing.
[11] Chiba, S., et al., Fatigue strength prediction of truck cab by CAE. Mitsubishi Motors Corporation, 2003: p. 52.
[12] Doddi, P. and S.S. Naidu, Design of carbon composite structure as an alternative material for an automobile chassis over a steel space frame using Ansys. 2022.
[13] Kasaba, K., et al., Evaluation of torsional rigidity of frame for electric Eco-Vehicle: deformation behavior of light thin shell structure subjected to torsion and bending. JSAE Review, 2002. 23(2): p. 251-258.
[14] Katdare, P. and S. Shilwant, Design optimisation of two wheeler (bike) chassis. International Engineering Research Journal, 2015. 2: p. 4273-4277.
[15] Lin, K.-Y., et al., Durability assessment and riding comfort evaluation of a new type scooter by road simulation technique. 2006, SAE Technical Paper.
[16] Mulla, I. and A. Qureshi, Design Analysis and Optimization of Two-wheeler Chassis for Weight Reduction. International Research Journal of Engineering and Technology, 2019. 6.
[17] Spanoudakis, P., E. Christenas, and N.C. Tsourveloudis, Design and Structural Analysis of a Front Single-Sided Swingarm for an Electric Three-Wheel Motorcycle. Applied Sciences, 2020. 10(17): p. 6063.
[18] Tripathi, S. and R. Ambikesh, Design and FEA of Motorcycle Frame Using Carbon/Flax Hybrid Composite as a light weight substitute to steel. 2021.
[19] Yamamoto, T., et al., Feasibility study of a new optimization technique for the vehicle body structure in the initial phase of the design process. 2007, SAE Technical Paper.
[20] Patel, M., et al., Lightweight composite materials for automotive-a review. Carbon, 2018. 1(2500): p. 151.
[21] 張燕玲,紀翔和,郭昱鼎,「電動摩托車車架分析」,產學報告,2022
[22] 張燕玲,紀翔和,鹿盛豪,嚴晧耘,江泓漢「電動摩托車車架分析」,產學報告,2023