Vibration energy transfer analysis in complex gearboxes: Simulation with experimental validation

The internal excitation in complex gearboxes includes harmonic excitation generated by periodic alternating meshing and impulse excitation generated by fault. However, the vibration energy transfer pattern of harmonic excitation and impulse excitation is unclear because of multi-layer interfaces and coupling paths between the excitation source and each sensor measuring point. In this paper, a vibration transfer analysis model for complex gearbox is proposed, and the vibration energy transfer pattern of harmonic excitation and impulse excitation in complex gearboxes is analyzed based on simulation and experiment. In terms of modeling, the instantaneous meshing stiffness of spur gears, the time-varying meshing stiffness of spiral bevel gears, and the equivalent support stiffness of splines are calculated, and the coupled system dynamics model is developed by considering the shaft flexibility. In terms of vibration energy transfer, the harmonic excitation signal is extracted based on the comb filtering method, and the impulse excitation signal is extracted based on the proposed wavelet matched period-group lasso method, and the evaluation indexes of vibration energy transfer for harmonic excitation and impulse excitation are defined respectively. The comparative analysis between experiment and simulation shows that the harmonic excitation is not monotonically attenuated in the transfer process, and the energy attenuation of the impulse excitation is positively correlated with the number of gear interfaces and spline interfaces passing through, with the attenuation at the spiral bevel gear interface reaching 61%. This study can provide guidance for selecting vibration and fault sensitive measuring points for condition monitoring.