分析动力学

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。

Chapter 5 indicates that multi-scale time-frequency analysis such as wavelet and EMD could offer more information of HRV than traditional linear analysis ways in time domain and frequency domain, which is a research trend with those nonlinear ways.

第五章将从研究方法上指出以小波分析和EMD为代表的多尺度时频分析可以比通常的HRV时频分析方法揭示更多的信息，和非线性动力学分析一起成为HRV分析的发展方向。

The fourth chapter talks about the weft carrier, in this part, we mostly introduce the big gripper shuttle in the comparative way and not only analyze the structure but also analyze the stress of the fatigable parts. In the fifth chapter, the shuttle box is our research emphasis, we start with the design principle and analyze its structure and the logic of the action of the parts. The sixth chapter discusses the shoot mechanism, builds its theory model and analyzes its law of motion from the view of kinematics and kinetics during the wefting. And then, we can consider the hydraulically shoot mechanism and comprehend its principle and some special parts. Subsequently, the content is about the flying of a shuttle, because the course of the flying of a shuttle is very complex, it is necessary to study the shuttle according to mechanics and to analyze its course of motion and its change of speed from the view of energy.

第五章谈的是梭箱，这部分从梭箱的设计原理入手，从结构的角度对梭箱进行分析，考虑到梭箱上各执行件间的动作存在一定的逻辑关系，还对执行件动作时间与控制作出论述，从中可以看出重型宽幅织机所独有的特性；第六章论述投梭机构，先构造出投梭机＿重型宽幅织机引纬机构与梭箱的设计＿构的弹性理论模型，从动力学的角度剖析投梭规律，随后分析液压式投梭的工作原－－理和一些特型元器件；第七章论述梭子的飞行运动，考虑到梭子飞行运动的复杂性，我们把梭子飞行运动划分为三个阶段，然后分阶段介绍其运动规律，在对梭子进行＿运动分析的同时还详细分析它的受力情况，在这一章的最后，我们对影响梭子飞行＿的因素也作出了讨论；顺沿这一过程，即是第八章对制梭机构的论述，在这一部分，、主要研究制梭过程与制梭力的情况，同梭子飞行过程一样，制梭过程也分为三个阶段，就每个阶段而言，我们都对其进行受力与运动方面分析，同时也就一些容易出现的问题作出讨论；最后两章是对纬纱交接机构和纬纱的退绕与张力控制作出讨＿论，鉴于这两部分不存在复杂的动力学方面的问题，论述重点便放在结构与原理的分析上面，包括分解纬纱交接机构，解析其动作过程，介绍储纬与纬纱张力的一些情况。

Firstly several vehicle dynamics models and tire models are analysed. Combining with the present condition and studying require, 3 dynamic differential functions about bodyworks velocity, roll and vertical displacement are gained. Furthermore based on the following rear wheel rev function and front-and-rear wheels vertical moving function, a 6-DOF, two wheels, lognitudinal dynamics model of the bus is set up.

本文首先对几种车辆动力学模型和轮胎模型进行了分析，结合现有条件和研究需要，得到关于汽车车身的速度、俯仰角和垂向位移的3个动力学微分方程，结合利用Simulink得到的前后轮垂向运动方程和将在后续研究中给出的后轮转速方程，建立了客车两轮6自由度纵向动力学模型。

In this paper,the raft is approximated by a thin plate with regular shape at first.Then the floating raft system is divided into several subsystems,such as plate raft,elastic foundation,etc,which are respectively modeled by four-parameter net method.After that,dynamic absorber and active absorber are put into a uniform frame to obtain the model of plate raft subsystem coupling with them.At last,according to the force and velocity relationship among each subsystem\'s interfaces,the entire plate floating raft system is modeled by subsystem structural admittance synthesis method.As the main structure of floating raft system is elastic,it is inevitably to study the optimization of actuators\' mounting positions before designing control law.In this paper,two new criterions are proposed for it.

本文首先将浮筏的中间筏架用一个规则形状的薄板近似；然后再将浮筏系统分解成若干个子系统，如板式筏架子系统、弹性基础子系统等，运用四端参数网络建立了它们的动力学传递方程，传递特性由导纳矩阵描述；接着，将动力吸振器和主动吸振器的(来源：ABC90论文00网www.abclunwen.com)分析统一于一个框架内，获得了与吸振器耦合的板式筏架子系统的动力学传递特性；最后，根据各子系统在各界面上的作用力和速度的相互关系，通过子系统结构导纳综合方法获得了整个板式浮筏系统的动力学传递方程，并在此基础上获得了系统的力传递函数模型。

In this dissertation, according to the theory of Mechanical Dynamics and Multi-body Dynamics, a simulation model of NJ2046 light off-road vehicle including suspension system, steering system and tires is built with the software CarSim and so the vehicle steering characteristics are analyzed with the step angle input of steering wheel.

摘要本文根据机械系统动力学、多体动力学理论，运用动力学仿真软件CarSim建立了包括悬架系统、转向系统和轮胎等模型的NJ2046越野汽车整车仿真模型，在此基础上分析了NJ2046越野汽车在方向盘转角阶跃输入时的转向特性，通过对不同车速、不同载荷条件下的仿真计算，得出了在这些条件下该车具有的不同表现特征，揭示了转向特性与车速、载荷和轮胎的内在关系。

Using the dynamic simulation software ADAMS to analyze the six-bar mechanism of shaping machine ;and through the virtual prototype,we get the optimum point from the optimization design of the acceleration and the press angle of shaping machine for the real machine;and we can get an example to the study of virtual prototyping.

简要介绍多体系统动力学的原理及多体系统动力学计算的积分方法，利用动力学仿真软件ADAMS，对牛头刨床的六杆机构进行分析，并通过虚拟样机技术，对牛头刨床加速度和压力角进行了优化设计。为实际的机构设计提供依据，也为虚拟样机技术的学习提供了实例

The purpose of shaft furnace reduction is to capture oxygen from iron ore and to produce iron. The experiments of reduce weight is used to measure the reaction ratio of CO and H〓 reduction iron ore.

通过建立一套测反应速率的装置，分别对球团矿、块矿用CO和H〓在不同条件下进行了还原反应动力学实验，建立了单界面动力学反应模型，根据理论分析和实验结果得到了不同原料的反应特性及相应的动力学参数。

The theory of multibody system dynamics is used to simulate valve trains' kinematics and dynamics characteristics, and the methods of establishing and analyzing the multibody system dynamics model for valve trains are discussed.

运用多体系统动力学的原理来模拟配气机构的运动学和动力学特性，讨论了配气机构多体系统动力学建模和分析的方法。

The makers say that population pharmacokinetic analysis of schizophrenic patients who were enrolled in clinical trials showed that no significant pharmacokinetic interactions occurred with benztropine, lorazepam or propranolol. 4 The makers also point out that since ziprasidone is not metabolised by the cytochrome P450 isoenzyme CYP1A2, smoking should not affect its pharmacokinetics.

制造者们指出，对加入临床试验的精神分裂症患者的总体药代动力学分析表明，无显著的药代动力学相互作用发生在苯扎托品，劳拉西泮或普萘洛尔之间。4制造者还指出，由于齐拉西酮不是由细胞色素P45O同工酶CYP1A2代谢的，所以吸烟应该影响它的药代动力学。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失