流体动压润滑轴承动特性参数识别的数字仿真

利用转子在高速动平衡机上做动平衡试验的同时，借助动平衡机的滑动轴承支承刚度可以 改变的特点，仅拾取转子与轴承之间的相对振动和滑动轴承本身的绝对振动，来进行滑动轴承动特性参 数的识别，数字试验表明此方法简单易实现、识别精度高和抗干扰能力强。     

椭圆轴承与圆轴承动力特性CFD数值分析

滑动轴承动力特性对旋转机械转子稳定性有着重要影响。将CFD动网格技术应用于椭圆轴承与圆轴承动力特性求解。在验证滑动轴承CFD动力特性求解模型准确性的基础上,建立基于CFD动网格技术的椭圆轴承动力特性求解模型,分析椭圆度、偏心率以及转速等因素对滑动轴承动力特性影响,比较分析椭圆轴承与圆轴承动力特性之间的差异。研究表明,椭圆轴承与圆轴承的承载力与刚度阻尼系数随着偏心率、转速的增加而增大;与圆轴承相比,椭圆轴承两个油楔形成两个流体动压区有效的增大轴承的阻尼,滑动轴承增加椭圆度可提高转子稳定性。     

镶嵌式径向滑动轴承静特性分析

分析计算了镶嵌式径向滑动轴承中油膜的压力分布、承载量、摩擦系数和流量，得出镶嵌式径向滑动轴承具有不同于普通径向滑动轴承的静特性。     

船舶推进轴系的动态模型

根据船舶轴系的结构特点与运动形式,先利用船体与轴承的有限元模型计算了轴系支承处的刚度,然后根据滑动轴承的运动方程,建立了滑动轴承油膜的有限元模型,分析了带有多个滑动轴承的船舶轴系的各轴承位置,并利用船舶系统的动刚度及油膜的动力特性以及螺旋桨的水动力,建立了轴系的动态计算模型,计算了在三个不同转速下轴系的动态响应。与实船测试的结果比较表明,轴系的动态模型是可信的,模型的建立为分析船舶在航行过程中的动态响应提供了方便。     

滑动轴承动态油膜压力的实时测量方法研究

针对滑动轴承的动态油膜压力的实时直接测量,设计一种滑动轴承动态油膜压力实时测量系统。分析聚偏氟乙烯（PVDF）压电薄膜传感器的工作原理,实验测定了传感器的性能特点,并设计相应的信号调理方法和信号显示软件编制。通过将PVDF压电薄膜传感器安装于Bently转子实验台的滑动轴承中,实时测量转子作用在轴承上的动态压力,讨论分析了动态压力信号。实验表明,PVDF压电薄膜具有较好的灵敏度、稳定性及重复性,能够有效地获得动态油膜压力信号,可应用于滑动轴承动态油膜压力的实时测量。     

轴承支撑特性及其对轴系动特性的影响

对滑动轴承型式试验台转子－轴承系统进行建模仿真计算,研究滑动轴承对转子动力学特性的影响。针对同一种轴承形式,研究不同轴承参数下的轴承支撑特性,计算出相应的轴承动特性系数。通过对比分析,给出主要轴承参数对轴承动特性系数变化规律。考虑基础支撑刚度的影响,研究刚度对转子系统临界转速随基础支撑刚度的变化规律。     

CFRP索斜拉桥动态特性的有限元分析及动态试验

介绍了国内首座CFRP索斜拉桥的工程概况;建立了该桥的三维空间梁壳杆系有限元动态分析模型,进行了结构动态特性有限元分析;进行了环境激励下国内首座CFRP索斜拉桥结构动态特性的测试,结合试验结果对国内首座CFRP索斜拉桥的动态特性进行了分析。同时,将实桥动态试验结果与有限元动态特性分析结果进行了对比分析。结果表明,有限元动态特性分析的低阶频率和振型与试验测得的频率与振型结果基本吻合。笔者等试验及相关研究分析结论可为CFRP索桥梁的动态建模、动态特性分析、抗震抗风设计及CFRP新型缆索材料在桥梁工程中的进一步推广应用提供一定的参考依据。     

三缸发动机机体的动态特性研究

机体是汽车发动机的主体结构，其动态特性影响发动机的振动和噪声，对机体的模态分析有助于机体动态特性识别及性能改进。以往的模态分析均局限于自由模态分析，但是系统的约束对其动态特性起到决定性作用。为使仿真计算能够真实反映机体的动态特性，应用I—Deas软件分析了机体实际工作情况下的约束模态，并利用脉冲激振进行了机体的模态试验，试验结果验证了理论模型的正确性，并提出了合理的减振和降噪措施。     

雨雾环境下温度传感器动态特性测试方法

针对雨雾环境下温度传感器的动态特性测试,对常规测试装置进行了改进,研究了雨雾环境的产生和控制方法,并提出了雨雾环境下传感器动态特性的试验方法,在此基础上对某传感器进行了试验,得到了其常规环境和雨雾环境下的动态特性试验结果,试验结果表明雨雾环境下传感器的动态特性会大幅提高;最后,对试验结果和试验中存在的问题进行了分析,明确了试验方法的改进方向.     

负荷传感器试验的准静态加荷方法研究

通过对叠置加荷方式工作过程的分析，讨论了非静态加荷问题。由于传感器和仪表的静态性能与动态性能的差异、动态性能的离散性，以及测量过程中采样频率、采样间隔和数据处理等因素均会对试验的力值计量精度产生影响，因此采用非静态加荷方式进行负荷传感器负荷特性试验会产生测量误差。理论分析证明，采用非静态加荷方法提高试验工作效率、保证测量精度的关键在于加荷速度的控制和正确的采样与数据处理方法。本文提出了准静态加荷这一概念，并对准静态加荷方法的实现及其在负荷传感器试验中实施的可行性进行了理论和试验研究。结果表明，受技术条件的限制，动态加荷是不现实的，而准静态加荷确是可行的非静态加荷方法。它满足负荷传感器负荷特性试验中试验工作效率高、保证测量精度、容易实施和生产成本低的要求。     

Optimal design of journal bearings

A new mathematical optimization technique, geometric programming, is used to optimize a number of journal bearing design problems. Though a few simplifying assumptions must be made in order to write the bearing design problem mathematically, no additional simplifying assumptions are required in order to apply geometric programming. Geometric programming is found to be a powerful technique for optimizing journal bearing design problems.     

SHAPE OPTIMIZATION OF A LUBRICATED JOURNAL BEARING WITH REGARD TO THE DISTRIBUTION OF PRESSURE IN THE FLUID

Journal bearings with water as lubricating fluid and a rubber layer in the bearing housing are considered for shape optimization. The aim is to vary the shape of the bearing housing in order to reduce the high maximum pressure, which occurs in common journal bearings, for a longer durability of the layer material. In the optimization process a design element technique is used applying NU R.BS for geometric modeling of the journal bearing shape. The FE-analysis of this coupled problem is carried out by use of lubrication elements and enhanced assumed strain elements for the incompressible rubber layer. An analytical sensitivity analysis of the nonlinear problem is described and some results of the shape optimization are presented.     

圆光栅测角仪的研制

介绍一台高精度、自动化的动态测量角度仪器。该仪器采用了高精度的回转空气轴系和多测量头的均化技术,减小了基准制造误差对系统精度的影响,采用了计算机系统控制测量过程、数据处理,实现了自动化测量。     

电子电路测量中计算机仿真系统的设计

目的 将计算机仿真系统用于电子电路的测量。方法 建立不同的数学模型,用高级语言编程。结果 将多媒体计算机模拟用于实现电子电路计算机辅助教学系统,结论实验中的计算机仿真技术可使教学更加直观。     

Journal bearings design for a novel revolving vane compressor

This paper presents the theoretical details of the journal bearing design for Revolving Vane (RV) rotary type compressor. The mathematical models, force analysis, and the theoretical design analysis for the dynamically loaded journal bearing of the compressor are presented. The variations of the minimum oil film thickness and the maximum film pressure developed are shown and the influences of design parameters, compressor configurations, and operating conditions on the journal bearing performance are described. For an air-conditioning compressor of 1.5 kW cooling capacity, the lowest minimum oil film thickness for lower and upper journal bearings is 6.6 μm and 4.3 μm respectively, when the cylinder is simply supported and the rotor is cantilever-supported. The lowest minimum oil film thickness for the journal bearing, which supports the cylinder, reduces to 4.0 μm if the cantilever-type support is used. Besides that, a short-fat configuration of RV compressor is favorable in the interest of lowering bearing forces.     

Investigation of tribological and mechanical properties of metal bearings

Copper, aluminum and tin-lead based alloys are widely used as journal bearing materials in tribological applications. Bronze and brass are widely used as journal bearing materials for copper based alloys. Zamacs find applications as journal bearing materials for zinc based alloys, while duralumines are chosen as journal bearing materials for aluminum based alloys. In addition, white metals are widely used as journal bearing materials for tin-lead based alloys. These alloys ensure properties expected from journal bearings. In this study, tribological and mechanical properties of these journal bearings manufactured by metals were investigated. SAE 1050 steel shaft was used as counter abrader. Experiments were carried out in every 30 min for a total of 150 min by using radial journal bearing wear test rig.     

Micro Air Bearing for a Microturbine

The dynamic characteristics of air bearings for microsystems are investigated. Micro air bearings investigated in this paper include journal and thrust air bearings. The dynamic thrust air bearing employs spiral groove configuration, and the dynamic journal air bearing is formed by a plain circular trench with a short journal length of L, a diameter of D, and a narrow radial clearance of C. The optimum values of the bearing system are explored and presented in terms of maximum load carrying capacity. Stability analysis shows that motion stability and load capacity impose contradictive requirements on the groove pattern of the thrust bearing. Shock tolerance analysis shows that the shock tolerance of the air bearing system increases with the bearing number, rotational speed, bearing aspect ratio of L/D, and initial equilibrium eccentricity ratio epsiv₀. A prototype of the turbine device has been realized using the recommended bearing configurations. The primary tests of the prototypes demonstrate that a stable operation of 15 000 rpm has been achieved.     

光学系统计算机辅助装调(CAA)机理的研究

文章对光学系统加工装调中影响象质的各种误差来源进行了分析,并对误差互补的可行性进行计算机模拟。从模拟的结果看,光学元件之间误差具有互补性,它使得计算机辅助装调成为可能。计算机辅助装调的方法步骤在文中作了详细的描述。     

国内外露天矿山台阶爆破技术

综合介绍了国内外露天台阶爆破技术,系统阐述了近年来在台阶爆破设计、计算机辅助设计系统、GPS钻孔定位、预装药等技术方面的新进展,详述了国内外露天矿台阶控制爆破技术在爆破参数设计、钻孔、药包布设、起爆系统、爆破安全、装药机械化以及计算机应用等方面的最新成果。最后,对我国露天矿台阶爆破技术的今后发展方向提出看法。     

基于ACTIVEX的模块化汽车空调系统通用分析软件的开发

本文介绍了汽车空调系统通用分析软件平台设计思想、基本组成、功能和实现过程。采用Ae—tiveX控制技术开发具有一定功能的可重复使用的零部件模块，并利用这些模块构成整个汽车空调分析系统，为新型汽车空调的开发提供帮助。该软件系统有良好的通用性和开放性，具备界面友好，组建新系统方便，计算速度快、精度高等优点。