弹性金属氟塑料径向滑动轴承润滑特性的实验研究及建模仿真

In recent years, much attention has been devoted to the design and operation of bearings made of elastic metal plastic (EMP).The surface of the bearing bush is covered by a layer of polymer PTFE(polytetrafluoroethylene).The physical performances of the polymer are quite different from that of metal.It can reduce friction because of its lower surface energy, and it is more difficult for the fluid to be adhered.Consequently, the slip will exist at the oil-bush interface.The journal bearings made of this material are researched in this article.Through test, the existence of slip is proven and the equation of the slip velocity for the EMP journal bearing is established when shear stress up to a certain value.Thus, the classical Reynolds equation is modified.The lubrication mechanism is analyzed by some simulation results.     

EMP径向滑动轴承热弹流分析与仿真

Elastic metal plastic (EMP) journal bearing is a kind of original bearing. Because of the specialty of the composite materials, elastic and thermal deformations of the EMP bush are much larger than that of common metal bush. In this paper, the three-dimensional mathematical model is established to analyze thermo-elasto-hydrodynamics (TEHD) of EMP. The numerical TEHD analysis software is programmed. An example is given to prove the lubrication performance of EMP. Supported by the National Natural Science Foundation of China (59775037)     

Inter-asperity cavitation for misalignment journal lubrication problem based on mass-conservative algorithm

Journal misalignment is common in journal bearings. When severe journal misalignment takes place, it affects nearly all aspects of bearing performance. This paper provided a comprehensive analysis of misaligned journal bearings based on two different mass-conservative models which appropriately took into account film rupture and reformation. The lubrication charac- teristics and performance parameters including the cavitation zones, pressure distribution, density distribution, oil leakage, load capacity, moment, and attitude angle were compared with the traditional lubrication model. The results showed that cavitation has great effect on bearing performances, especially when the surface roughness is large. Therefore, it is necessary to consider the effects of journal misalignment alongside inter-asperity cavitation theory in the design and analyses of journal bearings.     

流体动力润滑的紊流理论模式

1　IntroductionItiswellknownthatfluidflowsinsealsandbear ingsturnfromlaminarregimeintoturbulentonewhentheirReynoldsnumberbecomeshigherthanacriticalvalue .Theearliesttheoriesofhydrodynamiclubricationhavebeenbasedonthepresumptionofex istenceoflaminarflowregime .Inturbulentregime ,however ,thecharacteristicsofsealsandbearingsdif ferfromthepredictionsbytheoriessobased .Speciallubricationtheoriesbasedoncontemporaryturbulencemodelssincethelaterhalfof 190 0’swerethereforedevelopedtotaketheeffectsof…     

非解析径向轴承支承转子系统非线性动力特性分析

Nomenclaturex,y,x ·, y·-displacement and velocity of rotor-x,-y,x-·,-y·-displacement and velocity of rotor , di mension less¨x,¨y-acceleration of rotor¨-x,¨-y-acceleration of rotor ,di mensionlessω-rotating speed of rotor-ω-rotating speed of rotor ,di mensionlessx,y,z-Cartesian coordinates-x,-y,-z-Cartesian coordinates ,di mensionless2m-mass of rotorg-acceleration of gravityG-weight of rotor ,di mensionlesse=e2x e2y-mass eccentricity of rotorex,ey-mass eccentricity of rotor in thexan…     

新形势下我国学术期刊发展趋势探讨

随着我国加入WTO,学术期刊面临前所未有的挑战和机遇,我国学术期刊必将呈现出学术期刊学术性加强、学术期刊突出地域特征与专业化、学术期刊编辑出版手段现代化、学术期刊国际化与规范化四大发展趋势。     

广西沿海英语复合型人才需求状况的调查与分析

通过对广西高校(培养方)、学生(被培养方)和用人单位三方的问卷调查结果分析,提出了培养英语复合型人才的建议:结合地方发展情况,合理设置课程,改进培养方法;增强能力的培养和训练,更好地为地方经济的发展服务。     

Misalignment analysis of journal bearing influenced by asymmetric deflection, based on a simple stepped shaft model

The effects of journal misalignment on a journal bearing caused by an asymmetric rotor structure are presented in this study.A new model considering the asymmetric deflection is applied.Also,the thermo-hydrodynamic of the oil film in the journal bearing and straightforward elasticity theory are considered in the analysis.Based on the structure stiffness equivalent characteristic,a simple stepped shaft can reflect the entire complex structure model.The existing lubrication model,which does not consider this angle component,is not very precise for journal bearings.Film pressure,misalignment angle,velocity field,oil leakage,and temperature field were calculated and compared in the journal bearing analysis.The results indicate that bearing performances are greatly affected by misalignment caused by the asymmetric structure.A simple stepped shaft can effectively represent a misaligned journal bearing in a rotor-bearing system.     

Experiment and numerical simulation on axial compressive performance of autoclaved fly ash solid brick masonry columns

To study the influence of slenderness on the axial compressive performance of autoclaved fly ash solid brick masonry columns, compression experiments were conducted on 12 samples of autoclaved fly ash solid brick masonry column and 4 samples of fired clay brick masonry column. The damage patterns and compressive performance were compared and analyzed. The experimental results indicate that the compressive bearing capacity decreases as slenderness increases from 3 to 18, and the compressive bearing capacity of the autoclaved fly ash solid brick masonry columns is lower than that of the fired clay brick masonry columns. The formulae for the axial compressive bearing capacity of autoclaved fly ash solid brick masonry columns were derived based on the experiments. The nonlinear FEA program ANSYS was adopted to simulate the behaviors of masonry columns. By comparing the simulation results and experimental results, it is shown that the simulation results agree well with the experimental ones. The rationality and applicability of the simulation results were verified.     

板带轧机中支撑辊轴承的比较分析

介绍了板带钢轧机中支撑辊轴承技术的发展,就主要的新、旧两种型式的轴承从结构、使用寿命以及费用等方面作了详细的比较,并通过大量实际的数据证明了本文的结论-无键油膜轴承是最好的选择.     

Numerical investigation of microtexturing rings’ structure on the friction performance of bearing cells

We presented a numerical examination of the effect of microtexturing negative rings’ structure on the tribological performance of parallel bearing couples’ cell. Three mcirotexturing rings, which are circle, square and ellipse, were chosen and the analysis model were established. We used the Reynolds equation coupled with finite difference method and successive over relaxation Gauss-Seidel iterative method to solve the Newtonian flow’s hydrodynamics within a bearing couple. The effect of texture density and radius ratio (thickness) of the microtexturing rings were investigated on the tribological performance under the similar operating conditions. The numerical simulation reveals that: 1) The microtexturing rings’ structure can homogenize the local pressure much uniformly within the bearing cell. 2) The tribological performance is determined mainly by the microtexturing rings’ geometry and texture density, and the thickness of the rings’ structure can help to change the quantitative values. 3) The square and circle rings’s microtexturing surface can slightly improve the frictional performance with the bearing cells’ gap, while the ellipse ring’s surface may decrease the frictional performance. 4) The ellipse rings’ microtexturing surface can achieve the minimum spacing gap but the maximum friction coefficient of the bearing couple, and then the circle and square rings’ structure take the second and third place, respectively     

人民币区域化背景下泰铢外汇市场压力指数变动及影响因素研究

根据汇率变动的压力来源,引入包括泰铢的名义汇率、外汇储备、泰中利差和泰中通胀差等四个因素构建泰铢外汇市场压力指数,综合分析2002年1月至2013年8月泰铢汇率变动的压力来源,并对泰铢汇率压力变动趋势、特点和影响因素的贡献分析进行深入探讨。     

新时期科技期刊编辑应具备的基本素养

随着出版业的快速发展,学术期刊迎来了前所未有的发展机遇,因而对编辑的职业素养也提出了更新更高要求,为适应这种形势,做一名合格、称职的编辑,必须大力加强思想政治素养、业务基础素养、现代科技素养、专业能力素养和身心健康素养。只有具备了上述五种素养,才能胜任科技期刊的编辑工作。     

Effectof Film Force Nonlinearity on Unbalance Responseof a Jeffcot RotorJournal Bearing System

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基于报刊体制改革的地方高校学报发展研究

通过分析报刊体制改革对高校学报发展提出的新思路和新要求,结合地方高校实际情况,探讨当今地方高校学报的发展途径和方法。     

新时期科技期刊编辑的素质

在新的历史时期 ,科技期刊编辑面对知识经济带来的挑战 ,只有加强学习、增强责任感、提高业务能力 ,才能适应时代的要求 ,跟上时代的步伐。     

高校学报面临的问题及对策

高校学报性质上的局限性 ,使学报面临各种的问题。本文提出依托高校学科优势办出学报特色、扩大学报影响力、想方设法吸引优秀稿件、提高学报编辑水平等对策。     

网络论坛在建构科技期刊学术影响过程中的作用——基于对“体育在线论坛”(tiyuol.com)的考察

体育在线论坛是体育学刊编辑部三大网络平台之一。论坛通过内部挖掘,依靠兼职人员和热衷体育学术的网友实现自我研究和管理。论坛划分为"专题板块"、"体育学科"、"专家在线"、"站务及其他"四个板块群,具有学术资源共享、学术信息与观点分享、社会安全阀等功能。分析总结刘承宣、易剑东、上善若水3位忠实网友的体育在线论坛学术传播主题,通过借助网络论坛传播学术的方式,希望有更多的体育爱好者参与网络学术讨论。     

基于高职教育特色的高职学报特色定位研究

通过对国内外高等职业教育状况及高等职业教育学术研究成果的主要传播载体--学报的分析,我们提出高职学报要基于高职教育特色予以定位.     

论高校学报与教学科研工作的互动作用

高校学报是教学科研工作的重要组成部分，对教学科研有推动和导向作用，教学科研工作是高校学报发展的动力和源泉。高校学报与高校教学科研工作互相促进，共同发展。高校学报应提高质量，扩大影响，更好地为教学和科研服务。