考虑油膜惯性力时 Jeffcott 转子—挤压油膜阻尼器系统的突加不平衡响应特性

INFLUENCE OF FLUID INERTIA FORCES ON THE SUDDEN UNBALANCE RESPONSES OF JEFFCOTT ROTOR-SQUEEZE FILM DAMPER SYSTEM

转子系统的不平衡量可能由于偶然的原因而突然增大，转子系统在突加不平衡作用下的响应特性是一个很值得关心的问题。本文首先建立转子系统的微分方程，然后在考虑油膜惯性力的情形下，分析了转子的突加不平衡响应，并和不考虑惯性力的结果进行了比较。研究表明，考虑惯性力后，对常转速下的突加不平衡响应，瞬态响应的时间和振幅都减小了。对加速通过双稳态响应区时的突加不平衡响应，如突加不平衡发生在双稳态响应区之前，响应将沿双稳态中大解给出的路径并在双稳态结束时发生向下的跳跃；如突加不平衡发生在双稳态响应区之间，响应将沿小解给出的路径并不发生向下的跳跃。油膜惯性力能缩短双稳态跳跃后瞬态响应的时间。

This paper investigates the influence of fluid inertia force on the sudden unbalance response of flexible Jeffcott rotor supportedon squeeze film damper (SFD). In order to simulate the sudden unbalance process more accurately, this paper introduces a simple function which can better express the sudden unbalance process. It is found that for the sudden unbalance response at constant rotating speed, the fluid inertia can shorten the transient process and decrease the transient vibration amplitude. The amplitude of steady state response becomes smaller in most cases and the possibility for nonsynchronous responses to occur also becomes smaller when the influence of fluid inertia force is considered. For the sudden unbalance response of accelerating through bistable region, if the sudden unbalance occurs before the bistable region, the response will follow the large solution of the bistable response and will jump down when bistable region ends; if the sudden unbalance occurs within the bistable region, the response will follow the small solution and bistable jumping will not occur. For large fluid inertia forces, the transient time becomes shorter and the transient amplitude becomes smaller after sudden unbalance.