A study of friction microslip modeling for dynamic analysis of bladed discs with root joints

In machinery structures with joints, the contact pressures at contact interfaces are usually high enough to ensure that the contacting components stay joined and the gross slip does not occur. Nevertheless, the small relative slip over parts of the contact interface, i.e. the microslip, contributes significantly to the vibration damping. In the high-fidelity analysis of practical bladed discs, the macroslip model cannot provide sufficient accuracy for the predictive analysis of the properties of the friction damping in the contact interfaces. In this article, numerical studies of microslip damping effects is performed using 2D and 3D models of blade root joints. Analysis of hysteresis loops is performed to assess the influence of modeling parameters: choice of reference points, mesh configurations, and other physical parameters. The impact of the physical parameters, such as the contact geometry, friction coefficient, contact stiffness and tangential and normal loading, on the friction damping is numerically examined. The numerical results demonstrate the possibilities of microslip prediction using finite element modeling and show the microslip friction damping effects using simplified and realistic blade root models.