挤压式磁流变液阻尼器--转子系统的动力学特性与控制

用磁流变液代替常规挤压油膜阻尼器的润滑油,可制成阻尼特性受磁场控制的挤压油膜阻尼器,用于转子系统的振动控制。依据Bingham模型推导了磁流变液挤压油膜的雷诺方程及其解的表达式,给出了油膜流速、压力分布、油膜反力和阻尼器内磁拉力等的计算公式;以磁流变液阻尼器—刚性转子系统为例,理论分析了挤压油膜的力学特性和转子系统的不平衡响应特性;设计和制造了一种用于转子振动控制的挤压式磁流变液阻尼器;试验研究了支承在该阻尼器上的单盘偏置柔性转子系统的不平衡响应特性和控制方法。研究表明,磁拉力可降低一阶临界转速和临界振幅;油膜反力可降低转子系统在无阻尼临界转速处的振幅,并使一阶有阻尼临界转速增大;通过开关控制能使阻尼器具有最佳的减振效果,使转子振幅在全转速区达到最小。

DYNAMIC PERFORMANCE AND CONTROL OF SQUEEZE MODE MR FLUID DAMPER--ROTOR SYSTEM

Using magnetorheological(MR) fluid in place of lubricating oil in a normal squeeze film damper(SFD) can build a damping-variable SFD controlled by magnetic field, used to control the vibration of rotor systems. The Reynolds equation of MR fluid squeeze film and its resolution are derived based on the Bingham model, and the calculating formulas for flowing velocity, pressure distribution, reaction force of the squeeze film and the magnetic pull force inside the damper are presented. Using a rigid rotor supported on the MR fluid SFDs as an example, the mechanical properties of the squeeze film and the unbalance response characteristics of the rotor system are analyzed theoretically. A squeeze mode MR fluid damper used for rotor vibration control is designed and manufactured, and the unbalance response properties and control method of a single-disk flexible rotor system supported by the damper are studied experimentally. The study shows that the magnetic pull force can decrease both the first critical speed and the critical amplitude. The oil film reaction force can decrease the amplitude at the undamped critical speeds and increase the damped critical speed. The damper may have the best effect to make the vibration minimize within the range of all working speed by using on-off control method.