Investigation of structural-acoustic coupling in a thin-walled reduced-scale model of a car

The present paper describes the results of the recent research into simplified reduced-scale thin-walled models that can be used for experimental studies of vehicle interior noise. In many important cases such models can be described analytically, thus providing a developer with the effective engineering tools for prediction and mitigation of vehicle interior noise, especially on a design stage. The structural simplification in the models is based on understanding the physics of generation of predominant modes of structural vibrations by particular dynamic forces and of radiation of sound by the excited vibrations into the vehicle interior. The above-mentioned general approach is illustrated by a 1:4-scale simplified physical model of a car developed at Loughborough University – 'QUASICAR' (QUArter –Scale Interior Cavity Acoustic Rig). The model consists of a curved steel plate that is simply supported by two rigid sidewalls made of massive wooden panels. The effect of road irregularities exciting vehicle structural vibrations is imitated by electromagnetic shakers applied to the bottom of the steel plate. Measurements of structural vibrations and of the acoustic pressure generated inside the model at different positions demonstrate their good conceptual agreement with the results of theoretical predictions.