Considering the time-varying meshing stiffness

damping

torque fluctuation and backlash of the gear pairs

the dynamic governing equations of a two-staged gear system with 5 degree of freedom are established. The backlash of the gear pair is expressed into multinomial

and the meshing stiffness

input and output torque fluctuation are expand into Fourier series. By adopting the thought of Adomian’s decomposition method

the A-operator method （AOM） is used to obtain the response of the gear system on torque fluctuation. According to the simulation results

the torque fluctuation can cause the stronger vibration within some speed range

at same time

the separation phenomenon of lower speed gear pair takes place and higher dynamic loads are caused.