Optimization of the lower arm of a vehicle suspension system for road noise reduction by sensitivity analysis

• The 200–230 Hz range is the most important frequency for road noise reduction.
• The lower arm was found to be the most important design variable for road noise.
• This study proposed an improved plan for noise reduction using design optimization.

This study analyzed characteristics of road noise using vehicle tests and identified the 200–230 Hz range as the most important frequency for road noise reduction. Moreover, vibration sources in the vehicle suspension system were identified through transfer path analysis and coherence analysis. Using a finite element model of a vehicle suspension system, sensitivity analysis was performed to determine sensitive design factors. In order to achieve noise reduction using sensitivity analysis, the lower arm of the vehicle suspension system was found to be the most important design variable. For design optimization, we employed a robust and efficient sequential approximate optimization method, named PQRSM (Progressive Quadratic Response Surface Method) suitable for solving practical design optimization problems. The estimates based on a model proposed from optimization were in accord with the results of the experiment and road noise reduction was achieved by applying the optimally designed lower arm of the vehicle suspension system to a real vehicle.