Special Issue on Friction-Induced Vibration

Abstract

Friction-induced vibration constitutes a serious problem in all machines and mechanisms undergoing sliding motions.This problem is encountered in many industrial applications including bearings, disc brake systems, electric motor drives, robot joints, wheel/rail mass transit systems running on a curved track, machine tool guideways, etc.While friction is desirable in some applications such as disc brakes, its effects which include vibration, chatter, squeal, and chaos are detrimental to the operation of machines.All contacts and interfaces have inherent nonlinear stiffness characteristics.Their mechanical properties are different from the bulk materials which make up the basic elements.Other nonlinearities arise due to the velocity dependence of frictional forces, various nonlinear damping mechanisms, and other geometric configurations of the systems and subsystems in which interfaces are imbedded.The interaction between interface behavior and the overall system dynamics lead to the possibility of rich and complex dynamic behaviors, only one of which may be relevant to a particular application.To unravel such problems will require multidisciplinary understanding and teamwork.For example, tribologists have traditionally been concerned with understanding the physics, chemistry and mechanics of basic friction, lubrication, and wear phenomena.The interactions between friction, contact mechanics, and overall system dynamics have received limited attention from tribologists.On the other hand, dynamicists and control engineers study stability and response characteristics of mechanical systems in which the interface forces interact with inertia, stiffness, and damping forces.Therefore, the friction and contact models that are used are often oversimplified or inappropriately represented.As problems of high frequency system dynamics and noise take on increasing technological importance in industrial components, it becomes necessary to establish stronger interdisciplinary links so that critical issues can be better defined and more rapid progress made to ultimately provide designers with better models and predictive tools.