A multi-contact model to study the dynamic stick-slip and creep in mechanical frictional pair

抄録

The original Iwan-type model is always based on the quasi-static assumption, which neglects the dynamic properties of the frictional interface. In this paper, A Iwan-type multi-contact model is established to study dynamic stick-slip and creep in mechanical frictional pair. The individual contacts in this model follow a rupturing-reforming law, which enable the model to describe the relation between the fluctuation of friction force and the behavior of individual contacts. Thermal effect influences the rupturing of individual contacts, a process that contributes to a considerable difference in the prediction of friction force. Creep is examined in two aspects, namely, time dependence of nominal static friction coefficient and fretting response. This model exhibits the logarithm dependence of static friction coefficient on stationary time, a result that the quasi-static Iwan-type model cannot describe. The fretting responses under different parameters are investigated. The proposed model can satisfactorily describe the manner the average rupture threshold of individual contacts influences the maximum friction force and maximum fretting displacement. The energy dissipations under different oscillatory displacements are also evaluated. The relationship between tangential stiffness and average contact rupture threshold is studied under Gaussian and power law distributions of contact rupture thresholds. The paper elucidates that by introducing a new rupturing-forming law of individual contacts, the Iwan-type model can better describe the dynamic properties of the frictional interface.