Abstract ：

针对滚动轴承试验机的陪试轴承——推力滑动轴承承受瞬时冲击载荷这一问题,建立了推力轴承-转子系统的动力学模型和简化的轴承座结构变形模型,运用有限元法求解雷诺方程,欧拉积分法求解转轴的轴向动力学方程,ANSYS仿真获得轴承座的结构变形量,通过联合求解,得到了冲击过程中推力轴承油膜合力、最小油膜厚度和流量随时间的变化情况,对比了考虑和不考虑轴承座结构变形时推力轴承的冲击响应。结果发现:轴承座弹性变形对油膜合力和最小油膜厚度的影响不可忽略。不考虑结构变形时,油膜合力和最小油膜厚度的响应速度快得多,响应时间大约快了22%。弹性变形延缓了响应过程,起到了缓冲作用,并且缩短了达到稳态时所需的时间。考虑和不考...

Keyword ：

结构弹性变形 抗冲击 推力轴承 响应分析

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Abstract ：

基于静动联合分析方法,研究了三维拉杆转子中对中缺陷所造成的影响。通过使用三维有限元法和牛顿迭代法,说明了含缺陷拉杆转子的静动力学特性。对中缺陷导致了复杂的不平衡现象,包括质心偏移和随速度而改变的转子弯曲,而转子弯曲则明显降低了转子的稳定性,加大了其振幅。无论是否施加了动平衡,拉杆转子的弯曲特性决定了其振幅在超过临界转速后将会再次上升,在精度设计中应特别注意这一特点。同轴度公差是根据其稳定性特征所获得的,解释了为什么在拉杆转子中对径向定位表面的加工精度有着高度要求。此外,当对中缺陷存在时,采用不均匀的预紧也可减少对动态特性的不利影响。

Keyword ：

对中缺陷 非线性动力学 拉杆转子 转子弯曲

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Abstract ：

针对滚动轴承试验机的陪试轴承——推力滑动轴承承受瞬时冲击载荷这一问题,建立了推力轴承-转子系统的动力学模型和简化的轴承座结构变形模型,运用有限元法求解雷诺方程,欧拉积分法求解转轴的轴向动力学方程,ANSYS仿真获得轴承座的结构变形量,通过联合求解,得到了冲击过程中推力轴承油膜合力、最小油膜厚度和流量随时间的变化情况,对比了考虑和不考虑轴承座结构变形时推力轴承的冲击响应.结果发现:轴承座弹性变形对油膜合力和最小油膜厚度的影响不可忽略.不考虑结构变形时,油膜合力和最小油膜厚度的响应速度快得多,响应时间大约快了22％.弹性变形延缓了响应过程,起到了缓冲作用,并且缩短了达到稳态时所需的时间.考虑和不考虑弹性变形时,油膜合力的最大值和最小油膜厚度的最小值基本相同.分析表明,合适的轴承座结构刚度可以提高推力轴承的抗冲击能力.结构刚度不能小于某个临界值,太小可能造成某一瓦块的最小油膜厚度非常小,难以承受大的瞬时冲击载荷;同时也不能太大,不仅结构复杂,而且起不到缓冲的效果,可能会造成某些连接件过早失效.

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Abstract ：

Centration defect was investigated in a three-dimensional bolt-disk rotor according to the static-dynamic coupling analysis. The 3D finite element method and Newton iteration method were combined to study the static and dynamic properties of the defective bolt-disk rotor. Centration defect brings about mixed unbalance including constant mass eccentricity and speed-variant rotor bow. As a result, rotor bow leads to obvious stability reduction and vibration increment. No matter whether dynamic balance is conducted, entire bow determines that rotor vibration will still go up again after critical speed. This special feature of the bolt-disk rotor should be paid more attention in precision machining design. The allowable centration tolerance was obtained according to its stability characteristics which delivers a reason why the machining precision of radial location surfaces is highly demanded in the bolt-disk rotor. Uneven tightening was also presented to reduce adverse effects on dynamic properties when centration defect exists. © 2021, Editorial Office of Journal of Vibration and Shock. All right reserved.

Keyword ：

Bolts Defects Iterative methods

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Abstract ：

As the rotational speed of conventional rotor systems supported by oil-film bearings has increased, vibration problems such as oil whip and oil whirl have become apparent. Our group proposed the use of active magnetic bearings (AMBs)/bearingless motors (BELMs) to stabilize these systems. In such a system, measuring the variable stiffness and damping of the oil-film bearings, the current-force and displacement-force parameters of the AMBs/BELMs, and the residual unbalanced force is necessary to satisfy the stability of the rotor system. These parameters are the foundation for the rotor dynamics analysis and optimization of the control strategy. In this paper, we propose a method to simultaneously identify the parameters of the oil-film bearings and AMBs/BELMs along with the residual unbalanced forces during the unbalanced vibration of the rotor. The proposed method requires independent rotor responses and control currents to form a regression equation to estimate all the unknown parameters. Independent rotor responses are realized by changing the PID control parameters of the AMBs/BELMs. Numerical simulation results show that the proposed method is highly accurate and has good robustness to measurement noise. The experimental results show that the unknown parameters identified by the responses generated by different controller parameters are similar. To confirm that the identification results are correct, verification experiments were carried out. The vibration amplitude of the rotor was successfully suppressed by applying a force to the rotor in the opposite direction to the residual unbalanced force. The frequency response characteristics and unbalanced responses of the rotor estimated by the values of the parameters identified show good consistency with the measured results.

Keyword ：

active magnetic bearing bearingless motor oil-film bearing parameter identification rotating machinery vibration control

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Abstract ：

针对实际工况下超声时间差法在线测量滚动轴承保持架转速的噪声抑制及高速测量准确性问题,提出了一种采用频谱细化的滚动轴承保持架转速超声测量方法。通过引入自相关分析及快速傅里叶变换抑制时域噪声对超声回波脉冲信号的影响,使用线性调频Z变换(CZT)频谱细化算法提高滚动体通过频率的计算精度,进而提高轴承保持架转速测量准确性。28 000r/min下的高速滚动轴承保持架转速超声测量试验结果表明,该方法能够有效克服实际工况下的噪声影响,实现高速实际工况下轴承保持架转速波动的准确测量,测量误差在0.1%以内。

Keyword ：

保持架 超声测量 滚动轴承 频谱细化

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Abstract ：

针对实际工况下超声时间差法在线测量滚动轴承保持架转速的噪声抑制及高速测量准确性问题,提出了一种采用频谱细化的滚动轴承保持架转速超声测量方法。通过引入自相关分析及快速傅里叶变换抑制时域噪声对超声回波脉冲信号的影响,使用线性调频Z变换(CZT)频谱细化算法提高滚动体通过频率的计算精度,进而提高轴承保持架转速测量准确性。28 000r/min下的高速滚动轴承保持架转速超声测量试验结果表明,该方法能够有效克服实际工况下的噪声影响,实现高速实际工况下轴承保持架转速波动的准确测量,测量误差在0.1%以内。

Keyword ：

保持架 超声测量 滚动轴承 频谱细化

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Abstract ：

After considering the yawing motion, the dynamic model of the marine rotor-bearing system is developed on the short bearing theory. Theoretical analysis shows that the yawing motion causes gyroscopic moment and strong nonlinear time-varying transport inertia moment. The dynamic characteristics of the rotor-bearing system with and without yawing motion are compared. The result shows that the yawing motion significantly affects the dynamic characteristics of the rotor-bearing system, which makes the rotor system be dominated by the quasi-period. The yawing motion makes the rotor amplitude increase significantly at low speed. Finally, under the influence of yawing motion, the dynamic characteristic of the rotor shows chaos at high speed. © Published under licence by IOP Publishing Ltd.

Keyword ：

Bearings (machine parts) Dynamics

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Abstract ：

讨论了基于模型的系统工程和基于模型的设计的重要性,分析了其建模的差别。分析表明,设计必须在确定的、无歧义的基础上进行,虽然这个结果只能反复迭代得到,否则设计将无法实施。与系统工程建模允许采用某些自然语言相比,设计建模必须严格使用建模语言表达设计的结果。考虑到设计本质上是一个知识流动、集成、竞争和进化的过程,又必须同时满足物质需求、精神需求和社会需求,提出了一组关于设计功能知识分类和表达的建议:用传递函数表达功能单元在量值方面的知识,用由方块、输入向量、输出向量、控制向量和运算符构成的方块图表达功能单元之间的关系。传递函数由功能单元的输入和输出导出。当设计知识在分布式资源环境中由细分和专业化的设计知识服务提供时,确定的、无歧义的行为知识和结构知识表达也往往需要。因此,如何将上述关于功能知识表达的建议与任何系统工程建模语言的任何部分结合起来,确定地、无歧义地表达设计中功能单元或者系统的行为知识和结构知识,将是很有意义的研究。

Keyword ：

基于模型的设计 基于模型的系统工程 系统工程

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Abstract ：

研究了考虑船体垂荡运动时船用转子-轴承系统的动力学特性.首先,在非惯性参考系基于短轴承理论建立了船体垂荡作用下转子-轴承系统的动力学模型,结果显示垂荡作用下船用转子-轴承系统具有几何非线性特性;其次,采用数值方法,分析了系统的分岔图、最大Lyapunov指数、稳态响应、轴心轨迹、Poincare映射等,并与船体不发生垂荡时的转子系统动力学特性进行比较;最后,研究了垂荡激励幅值对转子-轴承系统非线性动力学特性的影响.结果表明:垂荡运动会显著地影响转子的动力学行为.在转速较低时,系统呈现周期1运动,垂荡对转子的运动特性影响此时占主导作用;随着转速的增加,系统出现准周期、周期2和双Hopf现象,具有周期1、准周期、周期2和混沌运动等复杂动力学特性.

Keyword ：

船用转子-轴承系统 垂荡 短轴承模型 非线性动力学

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