A shock absorber reduces vibration but at the same time it is a noise source. Structure-borne noise originated from a shock absorber considerably contributes to the car interior noise. In this paper, an experimental study on a real passenger vehicle was explored to analyze its noise and also presents a method to assess the quality of shock absorbers.
Based on the source-path-receiver model of the passenger car, the frequency response functions between the strut mount position and driver’s right ear position were measured. The structure-borne sound pressures originated from shock absorbers were evaluated using the transfer path analysis and those evaluated levels were compared with the measured sound pressures. The dominant frequency ranges mainly originated from shock absorbers were identified. It was very interesting that the dominant frequencies in the measured acceleration signals from the shock absorber strut mount were very close to those from sound pressure measurements. Therefore, the acceleration can be a substitute for the structure-borne noise analysis due to shock absorber. According to the performance test with abnormal shock absorbers, it was found that both the sound pressure and the strut mount acceleration show high level of peaks at same frequency ranges above the normal criterion frequency.
The experimental procedure and results on this work is applicable to establish a bench test on a real car and clarify the abnormality of shock absorbers.