货车心盘存在的问题及改进建议

针对货车心盘在运用与检修时存在的问题,分析其原因,并提出改进建议。     

端面摩擦磨损自动检测系统的设计

端面摩擦磨损试验可以模拟和检测面接触摩擦副的摩擦学特性。设计了端面摩擦磨损试验自动检测系统。首先在建立摩擦力和摩擦因数测量的数学模型的基础上,设计了摩擦力参数的自动检测系统,然后设计了端面试验机的智能化测控系统。使用结果表明,使用该自动检测系统的端面摩擦磨损试验机可实时检测和处理载荷、速度、温度、摩擦力和摩擦因数等参数信息,并以表格或图像曲线形式显示,有利于对试验材料的摩擦学特性变化作出实时、客观、量化的评估。     

SPT锥盘环盘无级变速器传动性能的研究

SPT锥盘环盘无级变速器是一款干摩擦(金属与非金属)驱动的摩擦无级变速器。建立了锥盘环盘无级变速器传动机构的数学模型,得到了压力凸轮给予摩擦盘间正压力的变化规律;应用软件ADAMS模拟了变速器传动机构的启动阶段、稳态运转阶段,摩擦盘驱动力矩和输出轴转速的变化规律。使用理论计算方法所得的摩擦盘间正压力和仿真所得结果进行了对比,验证了理论计算结果的准确性;最后探究了弹簧预压力、环盘轴上的负载力矩、摩擦盘间的摩擦系数、压力凸轮升角对变速器传动性能的影响规律。     

车轮滚动接触疲劳与磨耗耦合关系数值模拟

滚动接触疲劳和磨耗是车轮失效的主要方式。通过三维弹性体非赫兹滚动接触理论得到接触斑内的法向、切向应力和材料上不同深度处的最大切应力分布,以CL60钢和贝氏体车轮钢为例,基于"layer"滚动接触疲劳失效模型和Zobory车轮磨耗模型,分析LM型车轮踏面和75 kg.m–1钢轨型面匹配时轮轨接触条件和车轮材质对车轮滚动接触疲劳和磨耗竞争关系的影响。计算结果表明,摩擦因数为0.3时,CL60钢在小蠕滑条件下会发生滚动接触疲劳损伤,在大蠕滑条件下只有轴重大于30 t时才会出现滚动接触疲劳损伤,而贝氏体车轮钢只有在大蠕滑条件且轴重为30 t时,载荷循环次数小于1×105的情况下才会出现滚动接触疲劳损伤;摩擦因数为0.6时,CL60钢和贝氏体车轮钢在各种工况下的滚动接触疲劳损伤速度都小于相同条件下的磨耗速度。     

深海机械密封端面摩擦及变形特性研究

以深海推进器等水下设备用机械密封为研究对象,建立机械密封环模型,考虑深海变工况下接触端面摩擦因数的差异性,采用分离法分别对机械密封动、静环端面进行热-力耦合变形分析,并对分别考虑密封环热变形、力变形、热-力耦合变形的分析结果进行比较。结果表明:接触端面摩擦因数大小与介质压力、转速、液膜厚度等因素有关,端面摩擦因数随介质压力增大而减小,随转速增大而增大,随液膜厚度增大而减小;单一力变形、热变形分析与热-力耦合变形分析结果差别较大,热-力耦合分析结果要比单一变形分析更接近实际、分析更准确;瞬态工况下,端面温度及端面接触应力峰值均出现由外向内的变化趋势,端面接触状态受端面温度分布影响明显。     

桨-毂轴承材料扭动微动磨损行为研究

采用面接触扭动微动形式,以动力定位系统可调距螺旋桨桨-毂轴承摩擦副材料(CuNiAl-42CrMo4)为对象,以不同的角位移幅值模拟海水波动影响下的微动磨损行为,并结合扫描电子显微镜和超景深三维显微镜对磨痕形貌进行分析,探究桨-毂轴承摩擦副材料扭动微动磨损规律。结果表明,随着角位移幅值的增加,扭动微动依次运行于部分滑移区、混合区、滑移区,摩擦因数减小,同时磨损量增加,微动损伤中剥层机制所占的比例逐渐增加,且由于疲劳裂纹扩展的不利影响,实际运行过程中要尽量避开混合区。     

混铁车用平面心盘、球面心盘的实用分析

在混铁车的运行过程中,心盘不仅要传递混铁车运载铁水的重量,还要在车辆通过弯道时协调车体与转向架间的水平角度和垂直角度,对混铁车心盘的实用性研究尤为重要。     

基于动态数据的端面摩擦热-力耦合分析

为了更加准确地探索端面摩擦过程中的温度分布情况,使用端面摩擦过程中的实时动态摩擦因数和红外探头实测温度作为边界条件,在多场耦合软件COMSOL Multiphysics中进行热-力直接耦合分析,并利用红外热像仪对计算结果进行检验。结果表明:实时边界条件与数值计算相结合的方法可以准确地模拟出端面摩擦瞬态温度场;摩擦副之间的转速、载荷、摩擦因数是影响温度场分布的主要因素。     

车轮硬度对重载铁路货车车轮磨耗的影响

为研究车轮硬度变化对铁道重载车轮磨耗的影响,分析降低车轮磨耗的低成本方式,建立了装配转K6转向架的C80货车的车辆-轨道耦合系统动力学模型,并基于CONTACT程序与Archard磨耗模型建立了车轮踏面磨耗的仿真模型。通过建立的仿真模型来预测重载铁路货车车轮硬度对车轮踏面磨耗深度和车轮踏面外形的影响,结果表明适当增加车轮硬度会有效减小车轮磨耗深度,因此适当提高车轮磨耗区域内的车轮硬度可以有效降低车轮踏面磨耗,提高车轮的使用寿命。     

GY70型机械密封端面摩擦状态试验研究

机械密封端面摩擦状态包括干摩擦、边界摩擦、流体摩擦和混合摩擦.端面摩擦状态是决定机械密封工作寿命和密封性能好坏的关键因素.本文探讨了判断机械密封端面摩擦状态的摩擦因数法、工况参数法、Mayer法和相对膜厚法.对GY70型机械密封的端面摩擦状态进行了试验研究.研究表明,当弹簧比压为0.0866MPa、介质压力为0.45MPa、转速在1116～2940r/min范围内时,GY70型机械密封端面间的摩擦状态为边界摩擦.     

转载溜槽衬板磨损预测的DEM仿真方法

针对EDEM自动划分网格较稀疏问题,采用Hypermesh划分仿真模型网格,利用Herz-Mindlin接触理论的Archard磨损模型对转载溜槽磨损问题进行仿真,在网格单元上提取出漏斗和溜管衬板的接触能量和磨损量,分析了磨损量与接触能量的关系。假设转载溜槽衬板磨损深度为物料与溜槽衬板的使用时间为线性函数,根据现场衬板磨损量的测量值,将衬板的磨损系数关系的看作隐式的单变量方程,应用EDEM软件的仿真结果求解出磨损系数的标定值。分析了漏斗和溜管的磨损机理。该方法可用于转载溜槽的磨损预测。     

Modeling and simulating of center plate torsion behavior during bogie curve and turnout negotiation

In order to accurately simulating the tribological behavior of center plate of bogie, a model was built to calculate the torsional kinematics parameters of the center plate when a railway freight-car bogie passes through a curve and a railway turnout. According to the torsional kinematics parameters, a plate-on-plate torsional friction tester was built. The variation of the torsional angle, angular speed, and angular acceleration of the center plate under different conditions was investigated. The torsional angle was affected by the distances between bogie centers and the radius of the railway circular curve. For different railway track geometries, the torsional angle of the center plate during bogie curve and turnout negotiation ranged within 0.016°–1.08° and 0.04°–1.96°, respectively. The torsional speed of the center plate under the turnout condition was much higher than that under the curve condition. The torsional friction behavior of a center plate material was simulated with the tester according to the calculated results.     

铁路货车装载尺寸超限自动测量技术研究

提出了一种铁路货车装载尺寸超限自动测量的新技术。该技术利用计算机获取行进中的铁路货车的图像,实时提取货车的外形轮廓,并按照摄影测量原理解算货车的宽度和高度,根据铁路运输规范判断货车车厢尺寸是否超限。利用该技术设计制作的测试系统的具有很高的测量响应速度和较高的测量精度,达到铁路货车超限测量系统设计要求。     

基于Pro/E的翻车机的三维动画仿真

利用Pro／E软件建立了翻车机的装配体及其零件的三维实体模型,然后转成STL文件导入3ds max软件,对翻车机的工作流程进行三维动态处理,实现了一种新型三车翻车机的动画仿真。     

Computer simulation of wear

A digital record of the profile of a machined surface is processed by a computer to yield a number of wear-sensitive parameters such as mean slope and peak curvature. Numerical techniques are used to simulate removal of successive layers of the surface. Wear sensitive parameters are recomputed at each such removal. The results agree with experimental values obtained by a computer analysis of records, obtained by relocation profilometry, of a real wear experiment performed on the same surface. It is found that the variation with depth of wear of several surface parameters can be represented by the normal probability integral.     

金刚石切削黑色金属时刀具磨损机理的摩擦磨损试验

为了降低黑色金属金刚石切削过程中的刀具磨损,提高表面加工质量和精度,对刀具磨损机理进行了研究.通过黑色金属金刚石摩擦磨损试验,模拟了实际切削过程中的刀具磨损行为;分别采用扫描电镜(SEM) 、X射线能谱仪(EDS)以及拉曼光谱仪(RS)对工件表面形貌、实验前后工件表面化学组分变化以及金刚石磨损表面的晶体结构转变进行了检测,同时提出了用石墨化程度作为试验过程中评价金刚石磨损的指标.试验结果表明:金刚石的磨损主要与机械力和温度有关,摩擦速度和工件材料中的含碳量对其影响相对较小;石墨化磨损、扩散磨损和氧化磨损等磨损机理共存,其中石墨化为导致金刚石磨损的主要原因.结合红外热像仪测温和热传导理论推算,近似获得了摩擦界面的真实温度,且随着温度升高15％,金刚石石墨化程度显著加剧83％.作者提出,应当综合考虑热-力耦合作用下的刀具磨损机理,以便进一步探寻抑制刀具磨损的工艺措施.     

基于GPS的检衡车信息监控系统研究

利用全球卫星定位系统（GPS）技术，对检衡车进行实时的状态监测，以图形的形式实时显示检衡车的运行状况，记录检衡车的运行轨迹，可以提高检衡车运输的安全性，帮助管理者更好的制定全年检定计划及分配各分站栓衡车的数量。本文主要阐述了GPS的基本原理和监控系统开发的整个过程。     

波前编码景深延拓成像系统模拟实验研究

波前编码技术是结合光瞳位相调制和数字信号处理的一种新技术,由于它可以在不降低分辨率的前提下增加光学系统的景深,同时减小成像系统的体积和降低成本,因此该技术具有很好的应用前景.设计了一个波前编码成像系统,并联合ZEMAX和MATLAB软件对该系统进行了计算机成像模拟实验.模拟实验结果表明:在由相位系数决定的离焦范围内,波前编码成像系统能实现在不降低分辨率的前提下的景深延拓;当三次相位板系数为20π时,波前编码系统可以将传统光学系统的景深扩大60倍.     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

A boundary element formulation for three-dimensional sliding wear simulation

In this paper a boundary element formulation for three-dimensional sliding wear problems is presented. In the proposed formulation, the wear problem is described by modified boundary integral equations to include sliding wear. A linear wear law is used to model wear and an incremental sliding technique is adopted to solve the non-linear wear problem. Both cases, of one and both bodies losing material are investigated. The proposed method is validated initially by analysing the classic problem of pin-on-disc wear experiment and is subsequently applied to a total hip arthroplasty wear problem.The analysis demonstrates that the proposed boundary element formulation is efficient for solving sliding wear problems and particularly for cases involving complicated geometries, such as the artificial hip joint. Due to the boundary only modelling requirement, the computational effort remains low. In case of incrementing the sliding distance in advance, some optimization of the increment size must be carried out for the total CPU time to remain low and the final geometries of the bodies to be smooth. Using an optimum increment formulation, the solution speeds up as the sliding increments increase without great loss of accuracy.