Self - Excited Vibration Arising from Tribology - Dynamic Interaction

Abstract

An elastic contact model of a pad/disc system is developed which can give some explanations on self-excited vibration induced during continuous dry friction. Based on this model, it is possible to show that establishement and sustainability of self-excited vibration in disc brake system are linked to the interface properties as well as the physical properties of the disc brake components. It is shown using theoretical and experimental analysis that the regime of self-excited vibrations can be triggered when approaching any of the modified resonant frequencies of either pad or disc system. These frequencies are dependant upon contact stiffness value during self-excitation regime. Experimental investigations have also shown that contact stiffness during sustained self-excitation may increase monotonically upto 35% of its initial value due to continuous wear and sliding. One of the main findings in this work, is that the resonance of any of the system frequencies is linked mainly to the established value of contact stiffness due to wear, load and speed. Also, for each self-excited regime, there is a limiting frequency after which the self-excited regime either sustains at this frequency or change to another regime. Sudden changing of load or speed at this limiting frequency may cause the transition from one regime of self-excitation to another.