System dynamic instabilities induced by sliding contact: A numerical analysis with experimental validation

J. Brunetti (1, 2) , F. Massi (3) , Aurélien Saulot (1) , Mathieu Renouf (4) , W d'Ambrogio (2)

1 LaMCoS - Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne]
2 DIIIE / UNIVAQ - Dipartimento di Ingegneria industriale e dell'informazione e di economia
3 UNIROMA - Università degli Studi di Roma "La Sapienza" = Sapienza University [Rome]
4 PMMD - Physique et Mécanique des Milieux Divisés

Mechanical systems present several contact surfaces between deformable bodies. The contact interface can be either static (joints) or in sliding (active interfaces). The sliding interfaces can have several roles and according to their application they can be developed either for maximizing the friction coefficient and the energy dissipation (e.g. brakes) or rather to allow the relative displacement at joints with a maximum efficiency. In both cases the coupling between system and local contact dynamics can bring to system dynamics instabilities (e.g. brake squeal or squeaking of hip prostheses). This results in unstable vibrations of the system, induced by the oscillation of the contact forces. In the literature, a large number of works deal with such kind of instabilities and are mainly focused on applied problems such as brake squeal noise. This paper shows a more general numerical analysis of a simple system constituted by two bodies in sliding contact: a rigid cylinder rotating inside a deformable one. The parametrical Complex Eigenvalue Analysis and the transient numerical simulations show how the friction forces can give rise to in-plane dynamic instabilities due to the interaction between two system modes, even for such a simple system characterized by one deformable body. Results from transient simulations highlight the key role of realistic values of the material damping to have convergence of the model and, consequently, reliable physical results. To this aim an experimental estimation of the material damping has been carried out. Moreover, the simplicity of the system allows for a deeper analysis of the contact instability and a balance of the energy flux among friction, system vibrations and damping. The numerical results have been validated by comparison with experimental ones, obtained by a specific test bench developed to reproduce and analyze the contact friction instabilities.

Mots clés: Friction-induced vibrations; Mode coupling; Energy balance; Numerical tribology; Damping

Domaines: Mécanique [physics.med-ph]

J. Brunetti, F. Massi, Aurélien Saulot, Mathieu Renouf, W d'Ambrogio. System dynamic instabilities induced by sliding contact: A numerical analysis with experimental validation. Mechanical Systems and Signal Processing, 2015, 58-59, pp.70-86. ⟨10.1016/j.ymssp.2015.01.006⟩. ⟨hal-02093229⟩