Thesis-1994-Lang.pdf (12.8 MB)
An investigation into heavy vehicle drum brake squeal
thesis
posted on 2010-12-01, 11:51 authored by Allan M. LangMany mechanisms have been suggested for brake squeal over many years. In order
to identify the most appropriate of these mechanisms, an experimental investigation
has been carried out to define in detail the vibration characteristics of a squealing
heavy vehicle air operated drum brake on both a vehicle and a laboratory brake test
rig. This required the development of a novel 'scanning' technique for the modal
analysis of the rotating drum, which showed the presence of well-defined complex
wavelike modes. From these results, the dynamic behaviour of the drum, in particular,
is found to be in good qualitative agreement with the predictions of a simple 'binary
flutter' mechanism of squeal. Based on the role of rotor symmetry in this mechanism,
a means of decoupling, flutter modes is developed involving a reduction in the
rotational symmetry of the drum by means of attaching masses in a defined pattern
at its periphery. It is shown theoretically that such decoupling would be expected to
increase the dynamic stability of the brake, and experimental application of the
technique confirms its effectiveness in reducing or eliminating squeal. Practical design
aspects of reducing the rotational symmetry of the drum are considered, using finite
element modelling, and it is also shown that the technique can be effective in other
types of vehicle brake, such as disc brakes and hydraulic drum brakes.
The simple lumped parameter models used in the above work are inadequate as brake
design tools, however, and so a novel application of finite element modelling is used
to extend the principle of the binary flutter mechanism to a more detailed model of
a complete brake. This is shown to be capable of predicting known features of squeal
and may be used as a brake design tool for both the brake structure and the friction
material.
History
School
- Architecture, Building and Civil Engineering
Publisher
© Allan Michael LangPublication date
1994Notes
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.364780Language
- en