Experimental investigation of acoustic resonance properties of vehicle compartments

This paper describes the results of the experimental investigations of acoustic resonance properties of vehicle compartments carried out on reduced-scale simplified wooden models and on a real five-door saloon. The reduced-scale models had different degrees of complexity and were produced in two modifications: with rigid interior walls (modelling ‘body in white’ condition) and with walls covered by felt (modelling the absorption caused by the presence of vehicle trim). Experimental investigations included measurements of the acoustic frequency response inside the cavities. After establishing all resonant frequencies of the cavities, the spatial distributions of the corresponding acoustic modes have been measured at some fixed resonant frequencies. The obtained experimental results are compared with the results of finite element calculations. Finally, the results of the experiments on the reduced-scale models are compared with the measurements taken in the interior of the real vehicle: ‘Ford Fiesta’. The comparison shows that the results for reduced-scale models of sufficient complexity agree quite well with the results of measurements carried out in the real car.