Friction-induced stick-slip vibration and its experimental validation

Abstract

Friction is known to cause vibration in many situations and one particular kind of friction-induced vibration is in the form of stick-slip vibration, which is of fundamental significance in science due to its ubiquitous nature. In this paper, an experimental and theoretical study is performed to investigate friction-induced stick-slip vibration. An experimental setup with a sophisticated dual-pin-on-disc configuration is produced. A detailed solid model is constructed and modal tests are conducted to establish a novel, simplified 2-degree-of-freedom (DoF) theoretical model for the test rig. A series of stick-slip oscillation tests at several levels of normal load and disc velocity are performed and interesting vibration behaviour is discovered. A non-smooth Coulomb’s law of friction is adopted and identified for the 2-DoF model and the method of the Switch Model is used to deal with the non-smooth transitions from stick to slip and from slip to stick. The theoretical results predicted by the 2-DoF model agree qualitatively quite well with the experimental results. The differences between the two sets of results also suggest that there are challenges in realising regular stick-slip vibration in real machines/structures and capturing it theoretically. The main contributions of this work are the new designed test rig, the experimental findings, and the established theoretical model that can be used to reveal interesting dynamic behaviour of stick-slip vibration.