Abstract
Keywords - Brake, Noise, Vibration, Laser, Holography
Abstract - Recent developments in the holographic investigations of brake noise have produced a wealth of information concerning the vibrations of disc brake systems when high frequency noise (squeal) is being generated. Accurate measurement of the amplitude and phase of the 3D surface displacements of the disc rotor vibrations have been obtained.
Significantly large values of the in-plane component of the displacement of the disc rotor have been observed and it is considered that there should be much more attention given to this in-plane motion in modelling the interface between pad and disc.
The paper discusses the measurement and analysis of both out-of-plane and in-plane vibration of a twin calliper disc rotor during squeal generation. The technique makes use of the non-contact technique of holographic interferometry to record a set of three interferograms viewed from different viewing perspectives. Since each interferogram will comprise of a varying degree of out-of-plane and in-plane displacement relevant to their angular position, it is possible through the employment of algorithms developed from holographic theory to separate in-plane and out-of-plane and develop 3D displacement models of the real disc rotor.