路面入力引致車體振動與噪音

Abstract

汽車行駛中常會有振動與噪音產生，當振動頻率與車體自然頻率相同時，振動與噪音會產生放大的效果，造成行車品質降低。因此本文利用有限元素法分析White body模型(全車模型移除車體可活動之部分)，求得White body模型之模態振形與自然頻率，用以確認車體結構的主要振動特性，降低模型之未確定性。接著進行輪胎底部受垂直力作用時，全車模型之頻率響應函數分析其次在全車模型取出車內空腔結構，擷取空腔結構對應之頻率響應函數，做為車內空腔聲場分析之邊界條件，最後用邊界元素法軟體求解車內之聲場分佈。本文建立一套完整的分析流程，從結構模態分析、結構頻率響應分析進而進行車內聲場分析，藉此了解輪胎受到入力時車內振動與噪音的分佈情況。

Vibration and noise are usually generated when vehicles drive on the road, which may reduce the quality of ride comfort. This paper conducted the modal analysis for white body model by FE-analysis to compare with experiment results, in order to control the the uncertainties of the FE-model of the main structures. Then the frequency response functions of whole car model subjected to tire input force were conducted. The frequency response function of the cavity structure adopted from above mention whole body results were used as the boundary condition for vibro-acoustic analysis, then solve the pressure distribution in vehicle by boundary element software. This thesis established a completely analysis procedure, from modal analysis、frequency response analysis and vibro-aucoustic analysis, so that the vibration and noise of vehicle induced by input tire force from road surface can be predicted.