SUMMARYA numerical method based on the movable cellular automata (MCA) is presented. The proposed method aims to investigate the tribological characteristics of polytetrafluoroethylene, polyimide, and polyetheretherketone sealing polymer materials in the microscale. The microscale frictional behavior and wear processes of four sealing materials are vividly shown through this grid method. The formation of a mechanically mixed layer is visualized, and the rotation angles of the automata and number of worn cellular automata are obtained. Friction coefficients of the four sealing materials are calculated and compared on a microscale mesh. Tests are conducted on a special test rig of the seal. Scanning electron microscopy investigations reveal the wear patterns of the four sealing composites. Results indicate that the MCA simulations are consistent with the scanning electron microscopy investigations in terms of the wear mechanism. The proposed MCA method can be used to investigate and compare the tribological characteristics of different sealing materials, which will significantly improve the efficiency of sealing material selection.

Sealing rings in the wet clutch of heavy vehicles are vulnerable and weak. A key issue in designing and applying sealing rings is predicting the state of the seal contact quickly and accurately. A mixed-lubrication model of the sealing ring is developed on the basis of the load-sharing concept. A theoretical model is proposed to estimate the hydrodynamic and asperity contact behaviour of the sealing ring. The friction coefficients are calculated and compared under different operating conditions. The results cover the entire lubrication regime, including full-film lubrication, mixed lubrication and boundary lubrication. Experiments are conducted on a special test rig for sealing rings. General agreement is observed between the experiments and the simulations. The proposed method is simple but realistic and significantly improves the simulation efficiency. Designing the sealing ring quickly and accurately benefits the transmission system of heavy vehicles.

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A multiscale method based on numerical computation of finite element method (FEM) and movable cellular automata (MCA) is proposed. The proposed method aims to investigate the sliding contact of sealing rings in macroscale and microscale within a unified framework. The multiscale FEM–MCA coupling method based on mechanical and dynamic parameter transition has superior features such as multiscale time and multiscale space, which improve the efficiency of simulation significantly. Several certain positions of the sealing ring under different operating conditions were selected based on the thermal and structural responses obtained through FEM. Using the proposed multiscale method, we visualized and investigated several types of frictional information in microscale. Coefficients of friction (CoF) of all the cases were calculated and compared. The results indicate that the formation of a mechanically mixed layer (MML) has a significant function in reducing friction force. The thickness of the MML depends on the relative sliding velocity and external pressure. The CoF variations in the microscale model caused by the effects of MML differ from their macroscopic behaviors, but are in accordance with conventional friction theories.