Numerical and experimental study on dynamics of the planar mechanical system considering two revolute clearance joints

Abstract

Due to assembly, wear and manufacturing errors and clearance in the joints are inevitable. When the clearance is introduced into a mechanical system, the impact force in the clearance joint will cause undesirable vibration of the system. In this paper, the dynamic responses of the mechanical system with two revolute clearance joints are studied using computational and experimental methodology. The clearance joint is considered as force constraint. The normal contact force and tangential friction force between the journal and bearing in a clearance joint are modeled using a nonlinear contact force model considering energy loss and a modified Coulomb friction model considering a dynamic friction coefficient, respectively. A planar slider-crank mechanism with two revolute clearance joints is used to implement the study. The dynamic responses obtained from numerical simulation are compared with the experimental test. Numerical simulations and experimental tests for different clearance sizes and crank speeds are presented and discussed, respectively. The simulation results agree quite well with those of the experiment for different cases, which proves the accuracy and efficiency of the computational method for dynamics analysis of the mechanical system with two revolute clearance joints in this study. The investigation indicates that the clearances in revolute joints significantly affect the dynamic characteristics of mechanical systems, which must be considered in the precision analysis, design, and control of multibody systems, especially for high-speed machinery.