A parametric study of an unbalanced Jeffcott rotor supported by a rolling-element bearing
A parametric study of an unbalanced Jeffcott rotor supported by a rolling-element bearing
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DOI：
10.1007/s11071-020-05470-4
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发表时间：
2020-01-22
影响因子：
5.6
通讯作者：
Rix, Andrew I. J.
中科院分区：
文献类型：
--
作者：
Haslam, Alexander H.;Schwingshackl, Christoph W.;Rix, Andrew I. J.
滚动轴承广泛应用于工业旋转机械，因此迫切需要准确预测其对系统响应的影响。然而，由于转子动力学和轴承非线性之间的相互作用，这可能是具有挑战性的，并且很难为非线性响应提供物理解释。提出了一种新颖的方法，将由详细轴承模型支撑的Jeffcott转子与广义谐波平衡方法相结合，从而可以深入研究复杂的转子-定子相互作用。这允许转子的准周期响应，由于可变顺应，被捕获，以及间隙，环和定子顺应的影响，以及轴承的离心载荷对响应的研究。由于轴承的原因，观察到强烈的非线性响应，导致频率随着激励幅度的增加而发生大的变化，并出现稳定和不稳定的工作区域。当球通过频率与其中一个模态的频率重合时，变柔度效应产生了次同步力，导致了次共振。到目前为止，轴承的径向间隙对不平衡响应、由于柔度变化引起的自激和稳定性的影响最大。研究发现，引入外圈柔度会略微软化系统，轴承元件上的离心载荷会略微增加系统的不稳定区域，但这些影响都不会对所研究轴承的响应产生显著影响。当轴承安装在一个足够柔顺的定子上时，发现系统的行为是线性的。
Rolling-element bearings are widely used in industrial rotating machines, and hence there is a strong need to accurately predict their influence on the response of such systems. However, this can be challenging due to an interaction between the dynamics of the rotor and the bearing nonlinearities, and it becomes difficult to provide a physical explanation for the nonlinear response. A novel approach, combining a Jeffcott rotor supported by a detailed bearing model with the generalised harmonic balance method, is presented, enabling an in-depth study of the complex rotor-stator interaction. This allows the quasi-periodic response of the rotor, due to variable compliance, to be captured, and the impact of clearance, ring and stator compliance, and centrifugal loading of the bearing on the response to be investigated. A strongly nonlinear response was observed due to the bearing, leading to large shifts in frequency as the excitation amplitude was increased, and the emergence of stable and unstable operating regions. The variable compliance effect generated sub-synchronous forcing, which led to sub-resonances when the ball pass frequency coincided with the frequency of one of the modes. Radial clearance in the bearing had by far the largest influence on the unbalance response, the self-excitation due to variable compliance, and the stability. Introducing outer ring compliance was found to slightly soften the system, and centrifugal loading on the bearing elements marginally increased the system's region of instability, but neither of these effects had a significant impact on the response for the investigated bearing. When the bearing was mounted on a sufficiently compliant stator, the system was found to behave linearly.