Advanced squeak and rattle noise prediction for vehicle interior development – numerical simulation and experimental validation

Squeak and rattle (SAR) noise audible inside a passenger car causes the product quality perceived by the customer to deteriorate. The consequences are high warranty costs and a loss in brand reputation for the vehicle manufacturer in the long run. Therefore, SAR noise must be prevented. This research shows the application and experimental validation of a novel method to predict SAR noise on an actual vehicle interior component. The novel method is based on non-linear theories in the frequency domain. It uses the harmonic balance method in combination with the alternating frequency/time domain method to solve the governing dynamic equations. The simulation approach is part of a process for SAR noise prediction in vehicle interior development presented herein. In the first step, a state-of-the-art linear frequency-domain simulation estimates an empirical risk index for SAR noise emission. Critical spots prone to SAR noise generation are located and ranked. In the second step, the non-linear simulation approach calculates a quantitative measure for the SAR noise generated at these critical spots. This computation considers the root cause for SAR noise, the non-linear forces emerging from critical contact interaction, that is, stick-slip for squeak and repeated impact for rattle noise. In the third step, a shaker test validates the numerical results. Therefore, a full-scale test rig is built comprising an equipped vehicle interior assembly mounted on a frame. Thereby, the presented SAR noise prediction process featuring the novel non-linear frequency domain simulation approach is validated and applied to developing a complex vehicle interior assembly.