Analysis on Dynamic Performance for Active Magnetic Bearing—Rotor System

In the application of active magnetic bearings(AMB),one of the key problems to be solved is the safety and stabiltiy in the sense of rotor dynamics,The project related to the present paper deals with the method for analyzing bearing rotor systems with high rotation speed and specially supported by active magnetic bearings,and studies its rotor dynamics performance,including calculation of the natural frequencies with their distribution characteristics,and the critical speeds of the system.one of the targets of this project is to formulate a theory and method valid for the analysis of the dynamic performance of the active magntic bearing-rotor systemby combining the traditional theory and method of rotor dynamics with the analytical theory and design method based on modern control theory of the AMB system.     

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…     

校园规划建筑设计的节能策略探讨

随着我国人口增多、全民素质教育提高、资源枯竭、环境污染的加剧以及科技的发展和生活质量的提高,给校园建筑提出了新的课题,校园建筑节能设计也应是建筑可持续发展的重要内容之一。     

Application of the Non—Stationary Oil Film Force Database

The technique of non-stationary oll film force database for hydrodynamic bearing is introduced and its potential applications in nonlinear rotor-dynamics are demonstrated.Through simulations of the locus of the shaft center aided by the database technique,nonlinear stability analysis can be performed and the natural frequency can be obtained as well.The easiness of “assembling” the individual bush forces from the database to form the bearing force.makes it very convenient to evaluate the stability of various types of journal bearings,Examples are demonstrated to show how the database technique makes it possible to get technically abundant simulation results at the expense of very short calculation time.     

施工测量的基本方法及在民用建筑中的应用阐述

远古时代,人类在生活和生产中就已经开始总结自然变化规律,创造新的计算方法和计算准则。测量作为一种历史悠久的学科,是人类同自然界争斗的结果,也是人类赖以生存和发展的前提基础,是伴随人类计算形成的。随科学技术的发展和生产力的不断提高,测量学得以完善和发展,其应用范围也不断的扩大,成为社会发展的主要基础平台。在现阶段的民用建筑工程项目中,工程测量已成为工程中数据收集、整理的主要方法,也是工程得以顺利进行的必然依据。本文就民用建筑工程中施工测量的基本方法进行分析和阐述,并提出相应的完善措施。     

Approximate Tangent Plane Method for Calculating Surface Deformation in Elastic Contact Problems

lintroductionThenumericalsolutionofsurfacedeformationinthi-eedimensionalelasticcontactproblemsisthebasisofanalysisofnon-HertziancontactproblemsandtwodimensionalEHLproblems.Mostnumericalmethodsofsurfacedefol.lnationcalculationsubjectedtoanolinalpressuredis…     

电流变材料的设计、研制及其流变和应用性能研究

Electrorheological (ER) fluids, or suspensions, as one kind of smart materials, have very important and potential applications in electromechanical control due to their attractive features of rapid (with ms order), reversible, and controllable changes in rheological properties upon the application of an external electric field with kV/mm order[1～3]. Once ER fluids have met the engineering targets, they will bring revolution in several areas of industry and technology such as mechanics, trans portation, hydraulics and so on[4].     

基于高阶振动模型的建筑抗震性能检测

建筑物的抗震能力一直是建筑学领域研究的热点问题之一。传统的建筑震动检测方法都是已建立的建筑物的抗震信号模型,但是外界振动信号的突变性较大,从而降低建筑振动信号模型检测的精度。提出一种以无线传感振动信号为基础,配合高阶振动模型设计的建筑物抗震性能检测技术,准确的设计传感器对突变信号的检测规律,可以防止控制溢出被有效抑制,运用抗震控制律对抗震性能进行检测。仿真结果表明：该方法对突变信号较强的建筑振动模态进行抗震性检测,对检查中的干扰有着较好的抑制,提高了检测的准确度。