Robust Design Method for Dynamics of High-Speed Rotor System with Interface

The advanced aero-engine rotor is composed of different materials and connected by the joints such as bolted structure and spline, which shows discontinuity. The rotor always operates at high speed, and its bending deformation changes the contact status of joint interface, which leads to the stiffness loss and the change of the rotor dynamics. For the high-speed rotor system with interface, taking the spline structure as an example, the bend stiffness loss model is established, and the cause of bend stiffness loss at the joint is explained. On the basis of theory, the stiffness loss correction coefficient is introduced, and the influence of stiffness loss on the critical speed and bearing load are analyzed. In order to optimize the rotor dynamic performance, the robust design methods for modal properties and dynamic response behavior of rotor systems are developed with strain energy distribution on the rotor, aiming to reduce the stiffness loss and the sensitivity of the rotor dynamics. A numerical example is presented, the results show that optimizing the bearing support position and stiffness contributes to the reduction of the strain energy ratio on the joint and the sensitivity of the rotor dynamics, thus optimizing the rotor dynamic performance and its robustness.