Normal Damping Model of Mechanical Joints Interfaces Considering Asperities in Lateral Contact

Abstract

A mechanical interface behaves as the stiffness and damping when the interface is bearing a static normal force and a sine normal exciting force. For the interfacial normal damping, a calculating model was proposed. This proposed model studied the lateral contact (shoulder–shoulder contact) between upper and lower asperities in the elastic and elastic-perfectly plastic stages, which is neglected by other classical models. The normal force can be divided into a normal component and a tangential component when two asperities are contacting in dislocation. The relation between the loading–unloading normal component forces and deformation can be calculated, and then the strain energy dissipation between asperities can be gotten by integral. The friction energy dissipation also can be calculated based on the relation between loading–unloading tangential component forces and the slippage. Furthermore, the total interfacial energy dissipation can be obtained according to the statistical theory. Finally, the equivalent viscous damping is estimated using the vibration theory. The proposed model and classical models are compared by simulation and experiment, and it was found that the interfacial damping of the proposed model is more than the damping of the classical models. Moreover, the proposed model is consistent with the experimental results.