A comprehensive model for 3D revolute joints with clearances in mechanical systems

A mechanical system with clearance joints is well known as a nonlinear dynamic system that may exhibit chaotic responses under certain conditions. In the previous literature, the model for clearance joint is extensively investigated since it plays a significant role in prediction of kinematic and dynamic behavior of the system. A large volume of the literature only focuses on radial clearances, whereas, due to manufacturing and assembling errors, axial clearances also exist in joints, which have been scarcely considered. In this study, a comprehensive model for 3D revolute joints with radial and axial clearances is proposed. An experiment of the 3D revolute joint with clearances is firstly conducted to reveal the characteristics of the relative motion between the journal and bearing. According to the kinematic features, a model for 3D revolute joints with radial and axial clearances is proposed. This model presents a comprehensive description of the contact modes in which a group of contact force models are employed to reflect different contact-impact phenomena. Thus, the axial movement of the journal relative to the bearing and misalignment between the two elements could be characterized by this model. Moreover, a numerical simulation of the experiment is performed to validate the model presented in this study. Finally, a four-bar mechanism is taken as an example to illustrate its application and investigate the nonlinear dynamics of this system.