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Tire cavity noise has long been one of the main road noise issues. Various ideas for devices to reduce tire cavity noise have been patented or discussed in technical reports, but many issues remain for commercialization, and at present only some tires have appeared as products. Therefore, technology was developed for mounting Helmholtz resonators on the wheels, enabling reduction of tire cavity noise without placing restrictions on the tires. The advantage of this technology is that the cost and productivity targets needed for mass production can be satisfied without impairing the tire and wheel functions. The aim of this development was to construct low-cost device technology that is well-suited to mass production and enables reduction of tire cavity noise to an inaudible sound pressure without adversely affecting dynamic product marketability such as strength and durability performance and handling performance.

This paper describes the porous materials FE modeling scheme inside vehicle cabin using measured acoustic impedances to reduce the size of the matrices of the FE model while keeping the accuracy. The technique of measuring acoustic impedance using PU probe in a free field is introduced. Next, the surface acoustic impedance of the seat by the side of front is measured using this technique. And the vehicle cabin acoustic field is modeled by FEM using the measured surface acoustic impedance. For the accuracy verification of this model, the acoustic transfer characteristics inside vehicle cabin with and without the front seat are compared with the predicted and the measured transfer function. Moreover, finally the worth of this modeling method is considered.