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Boundary Layer Dynamics and Sound Generation
Technical Paper
2018-01-1900
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
In recent years, characteristic structures in the boundary layer of high-load contacts such as brakes have been reported, which substantially influence the dynamics of the tribological contact.
Usually, local assumptions concerning the friction behavior of these patches are used to reach global conclusions about the brake system. Several numerical methods (e.g. Cellular Automata) have been developed which employ such assumptions. The validation of these methods through measurement data tends to be laborious and costly.
Sprag-Slip elements are friction elements that are exclusively subjected to static friction, never undergoing sliding friction. Implementing such elements on a mesoscopic scale, it is possible to generate global descriptions of macroscopic stick and slip friction phenomena. Locally, these Sprag-Slip elements are similar to the patch structures in the tribological boundary layer of brakes.
The Sprag-Slip elements are suitable for describing the basic physics in the boundary layer between brake pad and rotor. Previous works have established their ability to depict principle macroscopic brake friction curves. In this paper, it is shown that characteristic boundary layer oscillations can represent characteristic braking behaviors, such as squealing and creep groan.
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Citation
Recke, B. and Ostermeyer, G., "Boundary Layer Dynamics and Sound Generation," SAE Technical Paper 2018-01-1900, 2018, https://doi.org/10.4271/2018-01-1900.Also In
References
- Ostermeyer, G.-P. , “On the Dynamics of the Friction Coefficient,” Wear 254:852-858, 2003.
- Ostermeyer, G.-P. and Mueller, M. , “New Insights into the Tribology of Brake Systems,” Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 222(7):1167-1200, 2008.
- Popp, K. , “Modelling and Control of Friction-Induced Vibrations,” Mathematical and Computer Modelling of Dynamical Systems 11(3):345-369, 2005.
- Hoffmann, N. and Gaul, L. , “A Sufficient Criterion for the Onset of Sprag-Slip Oscillations,” Archive of Applied Mechanics 73(1):650-660, 2004.
- Ostermeyer, G.-P. and Recke, B. , “Discrete Surface Dynamics: Distributed Sprag Slip Elements in Brakes,” SAE Technical Paper 2017-01-2531 , 2017, doi:10.4271/2017-01-2531.