Abstract
KEYWORDS – vehicle interior noise, high-frequency, airborne, SEA, TPA
ABSTRACT – It is assumed in general that vehicle interior noise above 500 Hz is mainly influenced by airborne path, and simulation studies for high frequency range in the stage of vehicle design are mainly performed by using airborne SEA vehicle model. However, this assumption seems to fail or succeed case by case for vehicle running modes. In the other hand, airborne SEA vehicle model is a sole simulation tool in vehicle level which can be applicable for high frequency bands. Therefore, it is important to understand the differences between the actual and the assumption for high frequency.
In this paper, firstly, the resemblances between the measured vehicle interior noise and the predicted interior noise by using an airborne SEA vehicle model were investigated not only in sound spectrum in 1/3 Octave but also in sound pressure level, loudness, articulation index, et al for several running modes of a sedan vehicle. Secondly, in order to verify the airborne SEA vehicle model, the interior noise predicted by airborne SEA vehicle model was compared to the airborne contribution synthesized from Operational Transfer Path Analysis.
The resemblances were most high for high constant speed running condition such as 100 KPH, especially for sound indices of articulation index and high frequency noise level. It was found that airborne SEA model could predict the airborne contribution with acceptable precision above 500 Hz or so. The low resemblances at running with WOT or at running at 60 KPH et al were due that the structure-borne contribution was still effecting at high frequency bands up to 1 kHz or so.