Characterisation of vehicle seat rattle noise from seat structural dynamics

The vehicle seat has robust structural dynamics characteristics which typically comprise of a maximum of three known vibration mode shapes at low frequencies (< 70 Hz). The goal of this paper is to investigate whether the seat rattle can be predicted and managed from its structural dynamics. The amplitude (loudness) and the high fractal dimensions of the signal (unpleasantness of the sound) have been studied. It has been shown that by modifying the critical frequencies, the seat rattle can be controlled and set in the early design phase. In addition to managing the frequency of the rattle, the knowledge of the seat vibration mode shape may help optimise the joint's properties. The locations and geometries of the joint for the seat sub-components, such as storage box or headrest, can be modified during the design stage in order to reduce the seat rattle noise.