Power Gearbox Modelling and Dynamic Simulation of a Geared Turbofan

This paper aims at the investigation of the vibration mechanism and dynamic response of the power gearbox using the established gear transmission system model. A comprehensive scheme was built consisting of modeling, assembling, boundary settings and loading to assess the deformation and vibration characteristics of the gearbox. Meanwhile, the transmission errors were included in the model to consider the effects of system errors, surface modification and manufacturing errors. Afterwards, the three –dimensional (3D) model was launched in Romax software to study the static and vibratory characteristics of the gearbox system. In addition, the meshing stiffness and transmission errors were analyzed. Finally, the gear surface modification and optimization were carried out to achieve the optimal stress distribution and reduce the maximum contact stress. The simulation results show that the maximum first mode acceleration response within the operating range was 8 g by setting the sensor at the planet wheel shaft pin. Meanwhile, the estimated transmission errors ranged from 0.13 ~ 0.15 μm. The maximum load for the planet roller bearing was 2933 N and would generate 1219 MPa contact stress, which was reasonable and acceptable. Nevertheless, the contact patch was unevenly distributed under the high-load conditions. To be specific, the maximum stress was 419 MPa locating at the gear surface edge, posing a failure risk. By performing the surface modification, the maximum stress has significantly dropped to 202 MPa and the corresponding region has moved from the edge to the surface center. The results has highlighted the importance of the proposed GTF gearbox system dynamic simulation scheme and generate a applicable approach for the transmission system engineering design.