整車車內噪音分析與改善

本研究將SUV運動休旅車的車內噪音分析及改善分三部分探討。第一部分透過阻抗管正向入射吸音率法，依序比較可取得之PU泡棉、雜色棉、白棉三種吸音材吸音性能，並將這三種材料各自性能最佳者，依其特性放置於不同部位施工，改善原車聲學包裝（Sound Package）的不足。第二部分則針對實驗車原況與目標車（進口高級SUV）之實際動態路試，利用頻譜分析探討車內噪音原因，並驗證其聲學材料對於整車降噪的效果。研究結果顯示經改善後，車內噪音得到明顯改善並優於目標車。第三部分則是對於第二部分無法降低之低頻噪音，分別利用操作模態（OMA）測試、空腔模態（Cavity mode）測試、實驗模態測試（EMA）及噪音傳遞函數（NTF）相關測試手法，找出低頻結構音貢獻最大之問題部位，施加含拘束層阻尼板對策，改善車內低頻振動與噪音。

關鍵字

正向入射吸音率；操作模態測試；空腔模態測試；實驗模態測試；噪音傳遞函數

並列摘要

In this study, the SUV (sport utility vehicle) interior noise is analysed and reduced in three steps. In the first step, the impedance tube normal incident sound absorption method is used to find the best sound absorption material among Polyurethane foam , shoddy and PP+PET. Afterwards, these materials are placed in different parts of the construction according to their respective characteristics, improved original vehicle sound Package. The second step is using spectral analysis to compare the vehicle interior noise in original condition and the target vehicle (high line SUV) in dynamic tests. analyse interior noise causes and validate its acoustic material for whole vehicle noise reduction. Results show that interior noise is improved and can be lower than target vehicle. The third step tackles the persistent low frequency noise found in the second step using operational modal analysis(OMA), cavity modes analysis, experimental modal analysis(EMA) and the NTF techniques. The structural part that contributed to the problem was found, imposed with constrained layer damping plate measures, improving low frequency noise and vibration in the vehicle.

並列關鍵字

Normal incident sound absorption ； Operation modal analysis ； Cavity Mode analysis ； Experimental modal analysis ； NTF

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整車車內噪音分析與改善

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