Rigid-flexible coupling dynamics modeling and vibration response analysis of different flexible components in a planetary gearbox

Planetary gearboxes are widely used in industrial systems. However, due to cost and safety limitations, obtaining vibration data under different health conditions in practical operating environments remains highly challenging. To address this problem, this study proposes a rigid–flexible coupled dynamic model considering different flexible components, which is used to simulate the vibration responses of planetary gearboxes under multiple health conditions with high fidelity. First, a criterion for selecting flexible components is proposed based on the vibration transmission paths of the gearbox. Subsequently, two rigid–flexible coupled dynamic models are established, in which the sun gear and the planet gear are treated as flexible bodies, respectively. The vibration responses on the gearbox housing under different operating conditions are calculated. The results show that, compared with the traditional rigid-body dynamic model, the proposed rigid–flexible coupled model can more accurately reflect the operating state and fault characteristics of the gearbox. Furthermore, the influence of different flexible component selections on the accuracy of simulation results is systematically analyzed. Finally, the vibration data generated by the simulation model are used as prior validation data for fault diagnosis algorithms, demonstrating that the proposed model can not only be used for dynamic analysis but also provide reliable data support for practical engineering fault diagnosis.