Reasons of nonlinear vibration of squeeze film damper and  summary of its structurel innovation
                                                                 CHEN Zhao, HE Lidong, LU Kaihua
(Key Laboratory of health monitoring control and fault selfrecovery for high end equipment, Beijing University of Chemical Technology, Beijing 100029,China)

Abstract: Aiming at the nonlinear vibration questions appeared in these rotor systems with squeeze film damper (SFD) under some bad conditions, some nonlinear vibration phenomena such as lock up, bistable response and nonsynchronous motion which cause the failure of SFD were introduced, and their causes were summarized in this paper, the means to improve the performance of SFD by optimizing the system parameters were discussed, and the improve directions of SFD in the future were suggested. A novel structure of SFD called integral squeeze film damper (ISFD) was particularly introduced and its stability improvement mechanism was analyzed, and the engineering application examples were given. The results indicate that compared to the traditional squeeze film damper, the integral squeeze film damper has excellent dynamic characteristics, which can significantly improve the stability of the rotor system and effectively avoid the occurrence of nonlinear vibration problems.

Key words: nonlinear vibration; cause analysis; optimize system parameters; structural innovation; integral squeeze film damper（ISFD）