Nonlinear dynamics of a support-excited flexible rotor with hydrodynamic journal bearings.
Nonlinear dynamics of a support-excited flexible rotor with hydrodynamic journal bearings.
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DOI：
10.1016/j.jsv.2013.12.021
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发表时间：
2014-05
影响因子：
4.7
通讯作者：
M. Dakel;S. Baguet;R. Dufour
中科院分区：
文献类型：
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作者：
M. Dakel;S. Baguet;R. Dufour
本研究的主要目的是预测的动态行为的车载转子安装在流体动力轴颈轴承在刚性支撑运动的存在下，目标应用是涡轮增压器的车辆或旋转机械受到地震激励。所提出的机载转子模型基于Kubishenko梁有限元。动力学建模考虑了轴和/或刚性盘的几何不对称性以及转子刚性支撑的六个确定性平移和旋转。根据轴承分析的类型，采用雷诺方程计算的液膜力为线性/非线性。因此，拉格朗日方程的应用产生了旋转转子相对于移动刚性支撑件弯曲的线性/非线性运动方程，该移动刚性支撑件表示非惯性参考系。采用隐式Newmark时间步长积分法求解这些方程。由于转子的几何不对称性和支撑件的旋转运动，运动方程包括可能导致横向动态不稳定性的时变参数项。通过稳定性图表、转子轨道、时间历程响应、快速傅立叶变换、分叉图以及庞加莱映射，研究和讨论了支承的正弦旋转或平移运动的影响、线性8系数轴承模型的准确性以及流体动压径向轴承的非线性模型的重要性。
The major purpose of this study is to predict the dynamic behavior of an on-board rotor mounted on hydrodynamic journal bearings in the presence of rigid support movements, the target application being turbochargers of vehicles or rotating machines subject to seismic excitation. The proposed on-board rotor model is based on Timoshenko beam finite elements. The dynamic modeling takes into account the geometric asymmetry of shaft and/or rigid disk as well as the six deterministic translations and rotations of the rotor rigid support. Depending on the type of analysis used for the bearing, the fluid film forces computed with the Reynolds equation are linear/nonlinear. Thus the application of Lagrange's equations yields the linear/nonlinear equations of motion of the rotating rotor in bending with respect to the moving rigid support which represents a non-inertial frame of reference. These equations are solved using the implicit Newmark time-step integration scheme. Due to the geometric asymmetry of the rotor and to the rotational motions of the support, the equations of motion include time-varying parametric terms which can lead to lateral dynamic instability. The influence of sinusoidal rotational or translational motions of the support, the accuracy of the linear 8-coefficient bearing model and the interest of the nonlinear model for a hydrodynamic journal bearing are examined and discussed by means of stability charts, orbits of the rotor, time history responses, fast Fourier transforms, bifurcation diagrams as well as Poincaré maps.