Dynamic modeling and analysis of multi-link mechanism considering lubrication clearance and flexible components

In mechanical system, lubricant is usually added into the clearance of moving pair to reduce friction, increase damping and prolong the service life of moving pair. Under the external force, flexible components are prone to tensile and bending deformation, which affects the stability and motion accuracy of mechanism. In the past, there were many studies on lubrication clearance and flexible components separately, but there were few studies on dynamic modeling and analysis of the lubrication clearance and flexible components, and there is no analysis on their nonlinear characteristics. In this paper, a new planar multi-link mechanism is studied. The vector model of lubrication clearance joint is established, and oil film bearing capacity model of lubrication clearance is established based on modified Pinkus–Sternlicht model. The absolute nodal coordinate formulation is used to model flexible beam element, and mass matrix and elastic force of beam element are modeled. By Lagrange multiplier method, the rigid-flexible coupling dynamic model of mechanism with lubrication clearance is developed. The effects of clearance value, driving speed and dynamic viscosity on dynamic response of mechanism are analyzed. By drawing the phase diagram, Poincare map and bifurcation diagram, the nonlinear characteristics of mechanism are studied. This research has important implications for the optimization design and life prediction of mechanism in future.