The acoustic cavity contains acoustic transfer function (ATF) of a cabin, the final transfer path of the vehicle interior noise. Therefore, the high accuracy level of the acoustic cavity model must be guaranteed to perform enhanced virtual vehicle simulations. In addition, because various shapes and patterns of interior cabins can be configured in the future mobility such as a purpose built vehicle (PBV) and an autonomous vehicle, it is necessary to develop the improved modeling method for the acoustic cavity to cope with this new trend. Accordingly, the development and application of the advanced acoustic cavity model for the vehicle interior cabin have been presented in this paper. Based on the large-scale ATF and modal tests on the cabin, the correlation study on the acoustic cavity model has been performed. For the accuracy improvement, an equivalent fluid layer and a narrow gap are introduced in the model for properly considering the effect of interior trim parts in the cabin. Also, inner-cavities inside the vehicle body panels are considered in detail. As the results, it is confirmed that the correlation level between the test and the simulation has been significantly improved. Furthermore, the usefulness of the new modeling method has been shown by application studies. First, the acoustic characteristics of the autonomous vehicle according to the cabin layout variation are discussed in terms of the impact on road-noise. In this research, the geometric condition of the first, second and third row seats and the shape of crash pad are considered as scenarios for the cabin layout variation of the autonomous vehicle. And, the changes on road-noise and acoustic characteristics caused by this cabin layout variation have been analyzed using the new advanced acoustic cavity model. Second, a solution to the problem of tail-gate cavity noise which is a type of wind-noise is presented through the analysis and control of the rear roof-rail inner cavity using the new modeling method. This new modeling concept for the acoustic cavity can be used for enhanced noise and sound simulations of vehicles. Also, it can be useful for analyzing the acoustic characteristics of the future mobility.
Mr. Seungchan Choi, Senior research engineer, Hyundai Motor Company