Avoidance of brake squeal by a separation of the brake ... - tuprints

Abstract
Brake squeal is a high-pitched noise in the frequency range between 1 kHz
and 16 kHz originating from self-excited vibrations caused by the frictional
contact between brake pads and brake disc. Since some decades, it has intensively
been studied and many countermeasures have been proposed, including
active and passive methods. It is known from experiments and has also been
proved mathematically that splitting the eigenfrequencies of the brake rotor
has a stabilizing effect and avoids brake squeal. In this thesis, this knowledge
is used to derive design goals for asymmetric, squeal-free discs. It is necessary
to split all eigenfrequencies of the brake disc in a pre-definable frequency
band to guarantee stability, inhibit the onset of self-excited vibrations and
thus avoid squeal completely. In order to achieve this goal, a structural optimization
of automotive as well as bicycle brake discs is conducted. Using
a novel, efficient modeling technique, large changes in the geometry can be
covered leading to a successful optimization in all cases studied. Optimized
automotive and bicycle brake discs have been manufactured and tested on
appropriate brake test rigs to assess their squeal affinity, and it is shown that
the optimized discs have a greatly improved squeal behavior. This validates
the mathematical theory behind the presented approach and demonstrates
that splitting eigenfrequencies of the brake rotor is a passive, low-cost and
effective squeal countermeasure applicable to a variety of brake systems.
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