Friction-induced instabilities: modal, transient analysis and experimental validation

The vibrations generated at the interface between the two bodies in friction are responsible for various noises such as squealing, juddering, hammering, hooting, etc. In order to model and understand friction-induced vibration phenomenon, two types of analysis, modal analysis and transient analysis, are compared in this article. This study has been made on a simplified system composed of two beams in contact. In modal analysis, instabilities appear when a pair of modes merges. Eigenvalues with positive real parts are identified as potentially unstable modes. In transient analysis, one speaks about instabilities when stick or separation zones appear in the contact surfaces. Results have been compared and both analysis give coherent and complementary results. An experimental validation has been made and shows a good correlation between experimental and numerical results.