Research On The Application Of The Automobile Interior Noise Source Identification

The NVH(Noise, Vibration, Harshness)of automobiles has been turning to be a critical factor for the customers'comments on the performance of automobiles, so how to reduce the interior noise has become the problem to be urgently resolved in order to improve the driving comfort. Additionally, it is of great importance to identify interior noise source considering the various factors affecting the interior noise. In this paper, noise was identified from the perspective of noise source identification, low-frequency, high-frequency and full-frequency noise were identified respectively.And comparative studied on the advantages and disadvantages of the noise source identification technology. The main contents are as follows:First, Low-frequency noise source identification based on CAE technology. It focuses on the application of FEM, BEM, ATV on low-frequency noise source identification. The finite element model and boundary element model were established, and the FEM, BEM and acoustic transfer vector (ATV) methods were respectively used to predict the low-frequency radiated noise. By the calculation of contribution of panels, the panels'contribution in the peak frequency was determined. Besides, the main noise sources were identified and ranked by the panel contribution analysis of sound pressure. And the structure design flaws were found, besides the directive proposition about structural optimization design was proposed. Through the study on the low-frequency noise source identification, the importance of virtual design of the vehicle development was greatly clarified.Second, high-frequency noise source identification based on SEA. It's mainly about the application of SEA in the high-frequency noise source identification. By establishing a SEA modal and applying the measured excitation source, the interior high-frequency noise of the vehicle was predicted successfully. Sorting the input power of interior noise with SEA, the main input panels of the interior noise was identified, and the main the main high-frequency noise sources inside the car ware identified from the perspective of sound radiation and transmission. Based on these, the feasible measures of noise reduction were proposed. And the significance of SEA technique on noise source identification was confirmed on the study platform of vehicle.Third, full-frequency noise source identification based on signal processing. It mainly research on signal processing in the noise source identification fields. And coherence analysis, partial coherence analysis and wavelet analysis were used to identify the interior noise respectively. Also, the partial coherence function and wavelet function of noise source identification MATLAB program were written. The contribution of various noise sources were quantified, making the noise contribution clearly. Through research on signal processing technology, the cost-effective position of the noise source identification of signal processing was confirmed in the OEM .