Dynamics Modeling of Faulty Gear Systems Considering Time-varying Mesh Stiffness

An accurate transmission system dynamics model can effectively provide early warning of faults or failures and can provide theoretical support for gear transmission system fault diagnosis. In this paper, the time-varying mesh stiffness of gears is solved based on the potential energy analysis method, and the root crack fault is introduced to propose the time-varying mesh stiffness of gears with faults and analyze the effects of crack depth and crack inclination on the time-varying mesh stiffness. Considering the time-varying mesh stiffness of the gear with root crack fault, a six-degree-of-freedom gear system dynamics model based on the centralized parameter method with bending-torsion coupling is established. The model is solved numerically and compared with experiments to verify the accuracy of the model. The results show that tooth root cracks affect the stiffness matrix of key parameters of the gear train, which in turn changes the characteristics of the model vibration response.