機車車架銲接結構之剛性與強度設計探討

本論文主要探討鋼材機車車架之銲接流程，針對銲接組裝後車架銲道進行品質評估，配合電腦輔助工程分析技術(CAE)進行車架結構剛性與強度設計分析，並以測試驗證其分析模型與結果。本研究機車車架之銲接製程是採用金屬活性氣體銲接(Metal Active Gas Welding, MAG Welding)，首先將車架主結構與次結構各銲接部位進行銲道品質評估，車架解體後取出銲接部位製作成標準試片，進行銲道形態、金相顯微、硬度試驗及殘留應力量測，藉以了解此車架結構之銲接品質與銲接製程參數之問題。接著使用ANSYS建立整車系統之有限元素模型以進行剛性分析，整車系統包括車架結構、懸吊系統及引擎組件(引擎本體與吊架)，車架結構之分析模型重點在於建立銲道部位模型，並透過車架側邊局部結構之三點彎曲分析與測試，獲得等效於實際結構之銲道機械性質，提升分析模型之準確性，懸吊系統及引擎組件則是透過約束元素及拘束方程式之設定，以完成整車系統之分析模型，即可進行整車系統之靜態彎曲剛性分析，同時進行實際結構之剛性測試。剛性測試考慮機車實際於路面行駛之邊界與負載條件，因此需設計可取代實際車架固定治夾具及剛性測試平台，測試結果透過位移與應變之量測，提供分析結果進行比對，並可藉由負載與位移之關係獲得整車系統及車架結構之彎曲剛性。最後根據品質評估及剛性測試，選擇車架結構承受負載較為嚴苛及銲道缺陷較為嚴重之部位進行銲接製程參數優化，並將完成優化之結果再一次進行銲道品質評估，提出最佳銲接製程參數，以提高車架結構之強度與剛性。

關鍵字

MAG銲接；銲道品質；機車車架；有限元素分析；剛性分析與測試；銲接製程參數優化；三點彎曲測試

並列摘要

The objective of this research was to investigate the structural stiffness and strength of a welded motorbike frame. In the first place, the baseline structure is investigated on its welding quality by using destructive approach. Frame is cut at the welding locations. Welding quality is evaluated by inspecting the welding morphology, hardnesses, microstructures and residual stress. A three-point bending test is then conducted on the welded joint of baseline structure to evaluate its stiffness and strength. Finite element analysis (FEA) is also performed to simulate the three-point bending by using a commercial code ANSYS. The correlation between FEA and test results provides us the material properties of welding line. Subsequently, the finite element model (FEM) of the welded frame is established. Metal Active Gas (MAG) Welding is adopted for the assembly of motorbike frame. The stiffness and strength test is also conducted on the completed structure system, including motorbike frame, suspension system and engine assembly. The analyses and tests of bending stiffness are performed. The test jig is designed to provide proper constraint equivalent to the real boundary and loading conditions. The structural deformations and strains are measured to compute the stiffness and strength of the completed structure system. Finally, the optimization of welding parameters is investigated based on the welding quality evaluation and stiffness test.

並列關鍵字

MAG welding ； welding quality ； motorbike frame ； finite element analysis ； stiffness and strength ； optimization ； three-point bending test

參考文獻

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[10] Gharibshahiyan, E., Raouf, A. H., Parvin, N. and Rahimian, M., 2011, “The Effect of Microstructure on Hardness and Toughness of Low Carbon Welded Steel Using Inert Gas Welding,” Materials and Design, Vol. 32, No. 4, pp. 2042-2048.

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國際替代計量

機車車架銲接結構之剛性與強度設計探討

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