查询词典 time of vibration

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。

According to structural characteristics of floating slab tracks, a track segment element was taken between two adjacent fasteners. For each element, rails were regarded as Euler beams supported by discrete viscoelastic supports. The fasteners and rubber supports were replaced by a linear spring and damp. So the vibration model of the floating slab track was established. In constructing vibration model of a metro train, each car of the metro train with two suspensions was modeled as a multi-rigid body system, in which rigid bodies were connected with each other by a linear spring and damp. Combining the potential energy of vertical vibration of the track with that of the metro train, the total potential energy of vertical vibration of the train and track was obtained. And then, the matrix equation of vertical vibration of the system was established using the principle of total potential energy with stationary value in elastic system dynamics and the "set-in-right-position" rule for formulating system matrices. The vibration responses of the system can be obtained by solving the matrix equation with the direct time integration such as Wilson-θ method.

摘 要：针对浮置板式轨道结构特点，取相邻2个扣件之间的轨道为1个轨段单元，钢轨视为连续弹性点支承Euler梁，浮置板视为弹性薄板，扣件系统及橡胶支座均模拟为线性弹簧及粘滞阻尼器，建立浮置板式轨道振动模型；将城轨列车中的车辆均离散为多刚体系统，各刚体之间通过线性弹簧及粘滞阻尼器相连，建立列车振动模型；将浮置板式轨道及列车振动势能叠加，得到系统竖向振动总势能；基于弹性系统动力学总势能不变值原理及形成系统矩阵的"对号入座"法则，建立此系统竖向振动矩阵方程；采用Wilson-θ逐步积分法求解此矩阵方程，得出此系统竖向振动响应。

In 1966, Ross solved the equation of symmetrical free vibration and got six matching solution, but he believed that it is impossible to find a solution which is useful in everywhere. In 1979, Goldenveizer printed a monography in which the uniformly valid representations of curved solution were published, but the representations of membrane solution were still not found. In 1988, Ruo-jing Zhang published the uniformly valid representation of six solutions for symmetrical free vibration and eight solutions for dissymmetrical free vibration for the first time.

但却碰到巨大困难。1966年，Ross给出了轴对称振动的6个匹配解，但却认为不可能求出全域一致有效解。1979年，Gol&denveizer等出版专著，给出了弯曲解的全域一致有效表达式，但仍然没有得到6个解中奇异薄膜解的全域一致有效表达式。1988年，张若京在其博士论文中第一次给出了轴对称6个解和非轴对称8个解的全部&全域一致有效表达式。

The wrappage placed on the vibration test machine dieblock so that it within a reasonable amount of time in accordance with regulations of the vibration waveforms, acceleration and vibration frequency, evaluation of wrappage's ability to withstand vibration and packaging ccultured mounted object protective ability test.

将包装件放在振动试验机台面上，使其在一定的时间内按规定的振动波形、振动加速度和频率进行振动，评定包装件承受振动的能力和包装对内装物保护能力的试验。

A new blasting vibration method,which is different from the traditional method to measure the delay time of detonating cord detonator,is proposed through studying the testing process and principle.

通过观察导爆管雷管延期时间的测定过程和研究测定控制原理，提出了与传统测定方法不同的爆破振动测定方法。

Under the action of horizontal earthquake forces, buildings with brick arch roof and floors vibrates as a whole, and at the same time local vibration takes place in the arch.

本文对砖拱楼盖的计算，考虑了楼盖的局部振动及房屋的整体振动两种影响，以及不同楼层处砖拱楼盖的不同地震反应。

The economic fundaments of vibration performance between electricity supplying and demanding are analyzed in this paper firstly, as well as the outcome of the power shortage in a long time periodically.

文中首先剖析了产生电力供需平衡振荡的经济机理，分析了缺电局面的长期演变特点。

In the Tang Dynasty, there was a very well-known geomancers, he名叫舒crowds, fluent in five patients the number of dumping reputation at home and abroad at that time, the ruling and opposition parties of vibration.

在唐代有一个很著名的风水师，他名叫舒绰，精通五行术数，在当时誉倾海内外，名振朝野。

According to rubbing mechanism lead to by various causes, the diagnosis rules about the features of vibration time waveshape, amplitude surge and amplitude increasing speed, two-dimension hologram Specturm purified, oil film pressure and journal whirling motion are put forward.

根据各种原因引起碰摩的机理，相应地提出了振动时波特征、振幅波动及增加速率特征、提纯二维全息谱特征、油膜压力特征和轴颈涡动特征等诊断规则。

A method is proposed by separating ambient noise signal and withdrawing the early-time multi-breakdowns of diesel engine based on natural gradient algorithm in the case that the number of vibration sources is unknown.

提出一种在振动源个数未知的情况下，采用自然梯度算法分离环境噪声信号的同时提取柴油机早期多故障的方法。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。