1. State Key Lab for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi'an, PR China
2. Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, Xi’an Jiaotong University, Xi'an, PR China
3. School of Mechanical Engineering, Xi’an University of Science and Technology, Xi'an, PR China
4. School of Mechanical and Electrical Engineering, Lanzhou University of Technology, Lanzhou, PR China