Abstract
The squeal noise generated by railway disk brakes is an everyday source of discomfort for the passengers both inside and outside the trains in stations. The development of silent brake components is needed and requires a better characterization and understanding of the phenomenon. This is the aim of the experimental and numerical investigations performed in the framework of the French AcouFren project and presented in this paper. The first part is concerned with the analysis of experimental data coming from bench tests in a lot of braking configurations including different brake pads. In the second part, the measurements are compared with the results of a large FE model of the brake taking into account the mechanical complexity of each component, especially the brake pads. Components models have been previously updated using experimental modal analysis but the whole model is a direct assembling of it, without updating. The assumption of unilateral contact and Coulomb friction at the pad/disc interface is sufficient to destabilize the sliding equilibrium of the brake and lead to self-sustained vibrations. Complex vibrating modes are computed in order to describe and understand the dynamic instabilities.
Highlights
The squeal noise generated by vehicles brakes is a difficult problem in the automotive and aeronautic industry and for railways
The disc-brake system of TGV trains is composed of a steel disc clamped to the bogie axle through a thin hub, a cast-iron "caliper-type" structure suspended to the bogie and controlled by a pneumatic system, and two symmetric pads fixed into the caliper on each side of the disc
The frequency content of the disc normal velocity measured by the vibrometer is very similar suggesting that an important part of the noise is radiated by the flexural vibrations of the disc
Summary
The squeal noise generated by vehicles brakes is a difficult problem in the automotive and aeronautic industry and for railways. Great progress have been done in the modeling of friction-induced instabilities [1] and brake squeal [2, 3] This is the case in particular for the TGV disc-brake system for which a refined mechanical modeling of the phenomenon has been carried out in order to understand the mechanism of squeal generation [4, 5, 6]. It seems that predictive industrial models can be developed and be used to specify and design technological solutions. The main assumptions and numerical methods are briefly exposed and the results of the stability analysis are compared with squeal measurements using modal frequencies, divergence rates and disc energy contributions
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