本文針對機車車架懸吊設計不同的三車(分別為上懸吊、下懸吊及下懸吊二版)，以實體元素建模並利用有限元素法分析其自然頻率、模態分析、簡諧分析，並以定轉速假設之引擎振源輸入頻譜，計算三車的模擬位移，觀察車架結構在駐車的怠速情形下，因懸吊方式的不同，是否對三車振動情形有何影響。最後由實驗結果與模擬結果進行比對，驗證並比較結果的異同。
綜合各分析的結果，發現下懸吊系統第一與第二版的振動皆大於上懸吊，下懸吊第一版又比第二版振動大。造成上、下懸吊系統車架之振動不同的原因推估可能是由模擬位移結果，因下懸吊受搖撼力矩所造成之振動位移影響較大，而在簡諧分析之結果中，搖撼力矩不論在汽缸或車架兩位置上，在頻率15Hz附近上下懸吊振幅值差距甚大，且下懸吊在15Hz附近(下懸吊Ver.1:15.5Hz、下懸吊Ver.2:15.9Hz)的振幅響應變化甚大。再加上引擎搖撼力與力矩頻譜分析之輸入中，以在15Hz與30Hz頻率下的輸入分量最大，故在此兩種因素下造成模擬位移疊加後的結果，以下懸吊系統振動大於上懸吊系統。

In this paper, solid element has been used to build the finite element model of three motorcycles which have different kinds of engine hanger, namely upper hanger, lower hanger, and lower hanger second edition, to analyze its natural frequency, modal analysis, harmonic analysis by using finite element method. Introducing the spectra of idle-speed shaking forces and moment which are simulated with the constant angular velocity assumption, the time-dependent displacements of three motorcycles have been computed and compared with the results of experiment. These three models in parking motorcycles conditions have been used to analyze the difference of vibration caused by different engine hanger system.
In the results of the analysis, it was found that vibrations of the first and second edition of the lower hanger system are greater than the upper, and the vibration of lower hanger is greater than lower hanger second edition. The reason of the difference of vibrations between upper and lower hanger system is that the vibrations of lower hanger caused by shaking moment are greater than shaking force. And at the cylinder and central of the frame, the difference of amplitude response near 15Hz caused by shaking moment between upper and lower hanger various greatly, specially the amplitude response of lower hanger. Additionally, the maximum of the input in the spectra of idle-speed shaking forces and moment is in 15Hz and 30Hz. Therefore, the result is that the vibration of lower hanger is greater than upper hanger.

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