Brussels, 07 Jan 2004
A consortium of Belgian and German researchers has produced a new set of laser technology tools to tackle the noise pollution caused by squealing breaks in both cars and trains.
Brake squeal is not only an irritating noise, however, as it also causes reduced system performance and leads to huge warranty payouts in the car industry. In this context, the partners in the EUREKA project, BRAKE NOISE, sought to improve the quality of brake designs in an effort to reduce costs for car manufacturers.
In the course of the project, the German multinational company, Bosch, LMS International of Belgium and the Vrije Universiteit Brussels pooled product know-how, computer modelling methods and fundamental research in order to learn more about the origin and nature of brake noise.
Experiments were performed to investigate the cause of brake squeal generation using laser-vibrometry, a technique devised by LMS that uses a laser beam to measure vibrations. 'We discovered that, next to braking pressure, the dynamics of the surrounding assembly is the most important parameter affecting the squeal frequency,' said Dr Herman Van der Auweraer, manager of research and technology development at LMS.
'Since braking can start at a very low pressure it's not something a driver can do anything about,' he explains. 'The brake design itself, including the assembly, must be adapted to eliminate the squeal. This is why computer models of the complete brake system during actual braking action are so important, because design alternatives can be evaluated without actually making them.'
Friction-induced vibration, the cause of brake squeal, is also a serious problem for many industrial applications containing systems with rotating or sliding parts, such as wheel/rail systems, turbine blade joints, electric motor drives and machine tools.
LMS is commercialising the results of the project by producing software tools and developing engineering services. 'We are integrating the project findings in a dedicated suite of measurement and analysis tools aimed at the brake manufacturing industry, and have been able to run a number of large brake noise consulting projects for brake and car manufacturers,' claimed Dr Van der Auweraer.
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