At 3:30 p.m. on November 26,2021, Assistant Professor Yeyin Xu(National Key Laboratory of Mechanical Structure Strength and Vibration, School of Aeronautics and Astronautics, Xi’an Jiaotong University) came to our school for academic exchanges at the invitation of the School of Electrical and Automation Engineering, Nanjing Normal University. The academic report entitled "Research on Nonlinear Motion and Bifurcation Dynamics of Gas Turbine Rotor System" was held in the meeting Room 501 of Qi Ming Building. The report was hosted by Deputy Dean Professor Shuye Ding of the school. More than 40 people including Professor Fuhong Min, Xinshuo Li, Yanwu Xu and postgraduate students participated in this academic report.

Assistant Professor Yeyin Xu, received a PhD in Mechanical Engineering from Southern Illinois University (Carbondale, USA) in 2020, and a PhD in Mechanical Engineering from Harbin Institute of Technology in 2020. He is currently an assistant professor of the National Key Laboratory of Mechanical Structure Strength and Vibration at the School of Aeronautics and Astronautics, Xi’an Jiaotong University and also a member of the Rotor Dynamics Committee of the China Vibration Engineering Association. He is served as a reviewer for "IEEE Transactions on Power Electronics", "The European Physical Journal Special Topics", "Journal of Applied Nonlinear Dynamics" and other academic prospects，and as the associate editor of “Journal of Vibration Testing and System Dynamics” and others. In 2020, he won the Youth talent support program of Xi'an Jiaotong University (Class A). He mainly engaged in nonlinear dynamics and control, rotor dynamics, nonlinear circuits and systems, neural network dynamics, etc. He has published more than 20 academic papers in "International Journal of Mechanical Sciences", "International Journal of Bifurcation and Chaos", "Mechanical Systems and Signal Processing". He is now in charge of one project of the National Natural Science Foundation of China Youth Fund, one of the sub-projects of the National Natural Science Foundation of China, and one of the technology development projects of China Railway First Survey and Design Institute.

This report focused on the nonlinear motion and bifurcation dynamics of the gas turbine rotor system. Assistant Professor Yeyin Xu separately shared the discrete mapping of nonlinear elastically supported rotor systems, and the use of Reynolds equations on the dynamic characteristics of fluid lubrication of sliding bearing oil films, and the nonlinear vibration displacement and speed of the rotor-sealing system under eccentric conditions based on pure elastic theory. The high-speed rotor system has a wide range of applications in the fields of machinery, textiles, transportation, aviation, chemical industry, and electric power. Rotor-related components are the core part of rotating machinery, and the methods introduced in this report can effectively explain, analyze and predict the nonlinear behavior to ensure the safety, stability and reliability of the rotor system.

At the end of the report, the teachers and students friendly discussed with assistant professor Yeyin Xu on the stability judgment and prediction accuracy with discrete mapping, and the advantages of the proposed methods for the rotor system. All the attendees had a deeper understanding of related knowledge and problems encountered in the research.