Prediction and identification of vehicle rattle noise caused by shock absorbers
2022-01-0364
03/29/2022
- Content
- A novel technology is proposed to predict vehicle rattle noise caused by shock absorbers. The model of shock absorber is developed by analyzing the force of moving parts, hydronic characteristic of valves and physical characteristic of oil. The model of mount, fixed between shock absorber and vehicle body, is developed with Maxwell method of combining series of spring and damping components. The characteristics of mount are measured under the specified frequency and amplitude conditions, the spring and damping coefficients of Maxwell model are identified using the measured data. The model of spring is developed by curve interpolation of measured data, considering the hysteresis properties of the real spring. The mass, wheel base etc. data of real vehicle are measured and the model of vehicle body is developed by Carsim using the measured data. The models of shock absorber, mount and spring are developed using Matlab/Simulink, and the vehicle body model is integrated into Simulink environment to establish the whole 4-wheel vehicle model. Then the exciting forces of shock absorbers imposed on the vehicle body are calculated using the whole 4-wheel vehicle model. Also the frequency domain characteristic of these forces are calculated by Fourier transform. Furthermore, the transfer functions of noise pressure/force from the shock absorbers to the cabin are measured in real vehicle. The frequency domain characteristic of these transfer functions are also calculated by Fourier transform. Then the rattle noise caused by the shock absorbers can be calculated using the exciting forces and the transfer functions in frequency domain. By inversed Fourier transform, the rattle noise is converted to time domain. A modified noise gate filter is developed to highlight the rattle noise, and the occurrence timing and conditions can be identified easily and precisely.
- Citation
- Xie, L., "Prediction and identification of vehicle rattle noise caused by shock absorbers," SAE Technical Paper 2022-01-0364, 2022, .