Innovative squeak noise prediction: An approach using the harmonic balance method and a variable normal contact force

A flawless interior acoustics is a customer requirement in automotive industry. Any disturbing noise e.g. squeak or rattle must be avoided to meet the customer's expectations regarding quality. This work presents an improved approach to predict squeak noise. For this purpose, a test rig generating the underlying stick-slip phenomenon by harmonic excitation is used and a corresponding finite element model is built describing the system's dynamic behavior. The Harmonic Balance Method is applied for solving the nonlinear equations of motion. The major difference to previous approaches consists in the implementation of a contact algorithm allowing variable normal forces in the contact domain. The calculated nonlinear system response is compared to existing methods using a constant normal force. The proposed method is capable of predicting odd harmonics, which is a significant improvement in assessing squeak noise. Furthermore, good agreement between simulation and experiment is observed which validates the approach.