Abstract: The multi-axle gear powertrain of a certain tracked vehicle. Firstly the mechanical model of multi-DOF bending-torsion coupled vibration is established according to a certain simplification principle, and based on the characteristic of the mechanical model, the finite element model of the system is established in ANSYS by combining the bending-torsion coupled vibration mathematic model and the finite element theory which takes into account the mesh stiffness and damping of the gear, and the supporting stiffness and oil film damping of the bearing. Complex modal calculation of the damped finite element model is carried out, and the characteristic of bending-torsion coupled vibration is analyzed. The vibration form, modal participation factor and effective mass of the coupled modal are discussed. The influence of time-varying mesh stiffness and mesh damping on the vibration modal is researched. At last the bending-torsion coupled vibration bench test is carried out for the gear system. The comparison between test data and simulation calculation result verifies the correctness of the finite element model, which lays the foundation for further dynamic analysis.

Key words: Effective mass, Modal participation factor, Powertrain, Time-varying mesh stiffness of the gear, Cosserat model, layout optimization, motional cable, virtual design, stabilized platform