刚性转子系统的碰摩与油膜非线性动力学耦合

通过分岔图、Poincarè映射、轴心轨迹讨论了不同强度和不同方位碰摩与油膜的非线性动力学耦合特性.研究结果发现,当转子产生2倍周期分岔后,碰摩分岔具有2倍周期的特征,即分岔图包括两部分.在转子发生2倍周期分岔区域,随着碰摩强度增加,在远离90°和270°发生碰摩时出现高倍周期分岔、概周期或混沌,而在90°和270°附近仍保持倍周期特性.当转子响应为概周期或混沌运动时,在90°和270°附近区域碰摩产生n倍周期分岔.当碰摩强度较小时,90°附近碰摩的分岔倍数高于270°碰摩的分岔倍数;随碰摩强度增加,90°和270°附近区域碰摩都达到2倍周期;而远离这两个区域碰摩的倍周期分岔数量增加,甚至达到...

Nonlinear Dynamic Coupling of Impact/Rub and Oil Film for a Rigid Rotor in Short Journal Bearings

Discusses the nonlinear coupling characteristics of the oil film and impact/rub for a rigid rotor in short journal bearings by virtue of bifurcation diagram, Poincare mapping, and trajectory of rotor centre, supposing the impact/rub is of different intensities and the rotor is being rubbed in different directions. The numerical results show that the multifold-period bifurcation, aperiod motion even chaos are found with the increasing impact/rub intensity and the bifurcation diagram falls into two regions when the rotor is running at the interval of rotating speed that its response is period-doubling motion without impact/rub and the direction of impact/rub is far off 90° or 270° , and that the period-doubling characteristic of the rotor response remains unchanged when the direction of impact/rub is in the vicinity of 90° or 270° . When the rotor is running at the interval of rotating speed that its response is aperiodic/chaotic motion without impact/rub and the direction of impact/rub is in the vicinity of 90° or 270° , the rotor response is multifold period motion; and when the impact/rub intensity is smaller, the multiple of period in the vicinity of 90° is higher than that near 270° . However, both are down to period-doubling with the increasing impact/rub intensity, while the number of its response period increases even its response becomes aperiodic/chaotic motion if far off the two region, and the region of its period-doubling response will gradually be extended with the increasing impact/rub intensity.