1. School of Mechanical Engineering, Xi'an Jiaotong University,Xi'an,China,710049
2. Xi'an Jiaotong University,Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System,Xi'an,China,710049
3. School of Mechanical Engineering, Xi'an Jiaotong University,State Key Laboratory for Manufacturing Systems Engineering,Xi'an,China,710049