Influence of conical shaft stiffness on the dynamic characteristics of flexible rotor

To achieve a highly efficient conical shaft design in aviation gas turbine engine's rotor system, firstly, a 4-DOF cantilevered rotor model is established to investigate the effects of the lateral, angular and cross stiffness of the rotor on the resonance speed of the pitching mode. The results show that increasing the lateral and angular stiffness, while reducing the cross stiffness, is beneficial for raising the critical speed of the pitching mode. Subsequently, using finite element method, the relationships between the cone angle, dimensionless radius, dimensionless span, and the stiffnesses of conical shaft are calculated. It is observed that, under various structural design constraints, the conical shaft with maximum stiffness exhibits different cone angles. Finally, experiments are conducted with flexible rotors featuring conical shafts of varying cone angles to validate the research conclusions. This paper provides guidance for the configuration design of rotors in aero-engine.