The role of system dynamics on the behavior of elastomeric friction

Friction induced vibration of an epoxy coated shaft rotating in an elastomeric bushing is investigated. This study investigates the manner in which system dynamics and friction mechanisms are responsible for friction induced vibration and noise generation. A test method was developed to measure the friction torque and the system and acoustic response of the sliding system. Several materials including a fluorocarbon elastomer, a polydimethylsiloxane, and a natural rubber were tested.

Three friction regimes were observed which were stick-slip oscillations, quasi-harmonic oscillations, and steady sliding. System stiffness and load were varied to observe changes in the critical velocities bounding each regime. System parameters were varied to determine sliding conditions leading to self-induced vibration, to establish how the character of vibration is affected, and to correlate friction torque with system and acoustic vibration for each elastomeric material.

A two degree-of-freedom, lumped parameter model was developed to simulate the effect of system dynamics on the sliding behavior of the elastomeric bushing. The comparison of simulated and experimental response using analyses in the time and frequency domain indicate the predictive model provides an excellent representation of stick-slip behavior at various operating conditions.