可适用的

The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.

理论分析和试验研究表明： 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的，具有摩擦动力学的本质，任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响； 2中心轴向载荷作用下，载荷增大使球轴承的固有振动频率升高，载荷越大同样的载荷增幅引起的频率升幅减小，足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响； 3轴向和径向联合载荷作用下，径向载荷不大时球轴承振动的固有频率基本不变，但是可能引起变刚度激励的非线性振动，出现新的频峰，过大的径向载荷将使部分钢球脱离接触，使球轴承的振动和噪声呈现不稳定状态； 4润滑对球轴承的振动和噪声特性有重要的影响，良好的润滑对振动有明显的抑制作用，润滑不充分时，振动和噪声的水平会有明显增高，一定条件下还会激发接触副中的谐振，发出啸声，造成接触表面的伤害，无润滑干接触时，短时的运转就会损伤接触副表面，使振动和噪声迅速增大，并随时可能引发严重的磨损和卡滞失效；接触副润滑良好时，油膜的"刚化效应"使球轴承振动的固有频率有所提高，润滑剂中含有弥散性污浊时，振动的幅度总体升高，但弥散性污浊不会改变球轴承振动的频率特性；浙江大学博士学位论文：球轴承振动的研究 5低速时，球轴承振动的基本特征呈现不稳定状态，随着转速的提高，球轴承振动的频率特性趋于稳定，固有频率频峰升高； 6理论分析表明，干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动，振动的幅值与谐波幅值成正比，实际球轴承中钢球的分布不可能完全均匀，波纹度的激励作用会随时发生；润滑接触的分析表明，波纹度的任意谐波分量均能激励球轴承的振动； 7球轴承的几何和结构参数分析表明，球轴承尺寸越大，径向、轴向和角振动的固有频率越低；钢球中心圆直径增大，球轴承的径向和轴向振动的固有频率基本不变，角振动的固有频率有所上升，振动的幅频特性基本不变；径向游隙加大使球轴承的径向振动固有频率降低，轴向和角振动的固有频率有所升高，径向振动幅频特性的幅值升高，而轴向和角向降低；钢球的数量增多使球轴承振动的固有频率上升，幅频特性的幅值下降，径向振动的幅值下降最为明显；外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高，轴向和角振动的固有频率降低，径向幅频特性基本不变，轴向和角向幅频特性幅值升高；内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降，振动幅频特性的幅值均有升高； 8试验对比表明，传感器采用探针式安装时，由于探针接触副接触特性的影响，钡(量得到的球轴承振动信号有失真，采用专门设计和制作的试验球轴承，以固定式安装加速度计，首次测量得到了球轴承振动的真实信号，通过对振动信号的分析，验证了球轴承振动的理论模型； 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析，以样本长度的均方根值作定阶上界，FPE做判阶准则，给出的AR谱光滑，频率分辨率高，是球轴承振动分析的简便而可靠的手段； 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间，时间间隔，频率范围，同样是球轴承振动分析的可靠的手段，可用作球轴承故障诊断技术。

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The main research contents are as follows:1. Through massive calculation, analysis and comparison, sum up the similarities and differences between the special-shaped cross sections and rectangular cross sections in mechanical features, between reinforced concrete special-shaped columns and rectangular columns in load-bearing capacity, ductility performance and provide necessary basic concepts and data for further understanding the characteristics of the special-shaped columns;2. Through massive elastic calculations and elasto-plastic analysis, under the preconditions of satisfying the code's requirements for axial compression ratio, limit value of lateral displacement and load-bearing capacity of normal section,oblique section and beam-column joint, under circumstances of different intensity of earthquake, structure dead weight, sort of site and column grid bay dimension, the variation regularity of maximum suitable height of structure, and thus sum up the maximum suitable height of structure for code for the purpose of macro-control while deciding the design scheme;3. Make a preliminary study on the stress feature of reinforced concrete special-shaped column and Z-shaped column of which the ratio of limb length to limb thickness is between 4~5 ,and the preliminary design method is suggested;4. Through elato-plastic time history dynamic analysis of typical projects, check up the weak storey of the special-shaped column structure and yielding, breaking and collapse mechanism to satisfy the earthquake resistant requirement to buildings of remaining stand under strong earthquake;5. Derive for project use simplified calculation formula of vibration period, suitable vibration period, suitable rigidity of special-shaped column structure through theoretical analysis, and provide an easy and practical method for deciding the structure scheme economically, safely and reasonably;6. Based on the study achievements in theory and massive analysis and calculations of this paper, sum up the regularities of inner force, deformation of special-shaped column structure and seismic conceptual design, and thus the suggection of seismic design of special-shaped column structures is presented.

本文研究的主要内容如下：通过大量的计算、分析和对比，总结出异形截面与矩形截面在力学特性、钢筋混凝土异形截面柱与矩形截面柱在承载能力、延性性能等方面的异同，为深入了解异形截面柱的特点提供必要的基本概念和数据；通过大量的弹性及弹塑性计算分析，在满足规程对轴压比、侧移限值及正截面、斜截面、节点承载力抗震验算要求的前提下，在不同抗震设防烈度、结构自重、场地类别及柱网开间尺寸情况下最大适宜高度的变化规律，并在此基础上总结归纳出异形柱结构的最大适用高度规定，可用于规程，以便于在确定方案时起到宏观控制的作用；对肢长与肢厚比在4～5的钢筋混凝土异形截面柱及Z形柱的受力特点进行初步探讨，提出初步的设计方法；通过对典型工程的弹塑性动力时程分析，检验异形柱结构的薄弱层及屈服、破坏、倒塌机制，以达到建筑物大震不倒的抗震设防要求；通过理论分析，推导出异形柱结构自振周期，以及适宜自振周期、适宜刚度的工程实用简化计算公式，为经济、安全、合理地确定结构方案提供简便实用的方法；在本文理论分析、计算以及大量的研究成果基础上，总结归纳出异形柱结构内力、变形的规律及抗震概念设计内容，并在此基础上提出异形柱结构的抗震设计建议。

If you are unfortunate enough to the lovelorn, please tell me, I will help you out, really, please contact me!

如果你不幸失恋了，请告诉我，我会帮助你摆脱困境，真的，请联系我啦！

China's plan to cut energy intensity by 20 percent and pollutant discharges by 10 percent between 2006 and 2010 is a case in point.

中国计划在2006年到2010间降低20%的能源强度和减少10%的主要污染物排放，就是一个这样的例子。