分形特征在湿式离合器磨合状态预测中的运用

针对湿式离合器试验过程中磨合状态的预测问题,提出利用摩擦转矩信号分形特征来预测和评价磨合状态的新方法.首先,分别阐述了摩擦转矩信号盒子维数和关联维数的计算方法;然后,在湿式离合器试验台上提取了磨合试验的摩擦转矩信号,并对信号进行了自相似性分析;最后,应用盒子维数和关联维数分别对摩擦转矩信号进行了分形研究.分析结果表明:盒子维数和关联维数都能定量描述试验过程中摩擦转矩信号的分形特征,随着磨合次数的增加,摩擦转矩信号的盒子维数和关联维数的波动范围都逐渐减小,并且最终收敛于较小的波动范围.因此,利用试验中摩擦转矩信号的分形特征能够在不开箱条件下定量地预测和评价湿式离合器的磨合状态.     

Boundary Lubrication,Wear-in and Hydrodynamic Behavior of Bearings for Liquid Metals and Other Fluids

Various material combinations are investigated in the form of thrust bearings in such fluids as sodium-potassium eutectic, xylene and spindle oil. It is found that with these fluids certain material combinations can be made to perform satisfactorily as hydrodynamic bearings by a process of wearing-in. With these unique combinations it is possible to obtain film thicknesses of the order of 10 × 10^?6 inches by extreme wear-in. The characteristics of bearings worn in to this degree are reported and mechanisms for the observed effects discussed.     

聚乙烯管道在燃气输配中的应用

介绍聚乙烯管道的特性,并针对在燃气输配中的设计及施工安全等问题,提出一些相应的措施或建议。     

Using Ultrahigh-Molecular-Weight Polyethylene in Hydraulic Drives

Russian Engineering Research - The use of ultrahigh-molecular-weight polyethylene (UHMWPE) in manufacturing is proposed—in particular, for the cuffs of hydraulic drives. The properties of...     

浅谈聚乙烯压力管件阀门制造的监督检验

介绍了聚乙烯管件、聚乙烯阀门的生产和应用的现状,产品分类和监督检验方法,监督检验的作用,详细介绍了聚乙烯压力管道元件、聚乙烯阀门监督检验的具体内容和要求。     

Failure Mechanisms in High-Density Polyethylene Rollers

This paper describes failure processes in plastic rollers that undergo rolling contact, and the effect of initial surface roughness upon wear and rolling fatigue. Experiments were performed with mating cylindrical rollers of high-density polyethylene (PE rollers) and chrome-plated cylindrical driving rollers. Surface roughness of the PE roller is affected by three successive transition processes. In the first period, the amount of wear can hardly be measured, although a reduction of surface roughness is noted. During the second period, wear occurs in proportion to the initial surface roughness. In the third period, wear becomes independent of the initial surface roughness, and increases in a manner exponential to load. At the end of this period, small cracks appear randomly, and grow into pits. Roller fatigue Life, defined by the time when cracks appear, is shown by an S-N curve. It is found that fatigue limiting stress, represented by Hertz stresses, is about 10⁷pa.     

Evaluation of Tribological Behaviour of Polymeric Materials for Hip Prostheses Application

The tribological (friction and wear) behaviour of different polymeric materials was evaluated for hip prostheses applications. First, three polymeric materials were tested with fixed conditions of contact stress and sliding velocity. In a second phase, the material which presented the best results was selected. Its frictional behaviour under dynamic conditions of contact stress and sliding velocity was evaluated.     

聚乙烯衬板在煤运转粉料仓中的应用

本文简要介绍超高分子量聚乙烯的特性及其衬板在煤运转粉料仓中的安装方法、注意事项及使用效果。     

聚丙烯输送泵的特点及改进措施

本文对聚丙烯装置原料输送泵的抗汽蚀性能、轴密封性能以及运行中的异常现象进行了分析,并进行了部分改进。     

Orienting Mechanism of Robots and Arm Prostheses with Linear and Rotary Drives

A mechanism is proposed for orienting motion of anthropomorphic robots and arm prostheses, with limited rotation of the output component. The linear displacements and drive forces required for specified rotations and the torques at the output component are determined. A simplified control algorithm is devised.     

集成机器人磨削的定制式假体制作方法研究

影响非骨水泥假体长期稳定的因素是无菌松动,微动和应力遮蔽通过破坏假体近端的骨整合导致假体的无菌松动,而微动和应力遮蔽与假体的力传递相关。定制式假体的设计模型来源于病人股骨的CT数据,它建立了有限元模型与手术模型的一致性,通过有限元模型上的力传递分析,优化假体的设计和假体与髓腔的匹配,控制手术后假体上的力传递,避免假体近端大的微动和应力遮蔽而破坏假体在髓腔中的初期稳定性,促进假体近端的骨整合。针对定制式假体,发展一种新型的集成技术,形成定制式假体设计、有限元分析和制造一体化,特别是采用CAD/CAM/Robot集成技术加工定制式假体,在建立CAM软件空间各单元与机器人工作空间对应各单元一致性基础上,提高了假体的制造精度。仿真和实验结果表明,有限元分析方法可以控制假体上的力传递,机器人磨削柄体的误差小于0.9mm。     

X射线荧光光谱法在聚乙烯生产中的应用

利用X射线荧光光谱分析仪可以快速、准确地测定聚乙烯树脂中Al，Ti元素的含量，而且精密度好，非常适合于产品生产中间控制分析。同时在对定期校准仪器的飘移、采用PH模式对校准曲线进行线性回归校准方面做了一定的说明。     

高密度聚乙烯硅芯塑料管拉伸强度测量的不确定度评定

介绍了用CSS44100电子万能试验机测定地下通信管道用高密度聚乙烯硅芯塑料管拉伸强度的试验方法，并对试验结果的测量不确定度进行分析评定，找出了影响拉伸强度测量结果的主要因素。     

高密度聚乙烯硅芯塑料管拉伸强度测量的不确定度评定

介绍了用CSS44100电子万能试验机测定地下通信管道用高密度聚乙烯硅芯塑料管拉伸强度的试验方法,并对试验结果的测量不确定度进行分析评定,找出了影响拉伸强度测量结果的主要因素.     

对全密度聚乙烯反应器现场组装的质量控制

在对全密度反应器现场施工中难点和关键点,如锥体和筒体组装成形尺寸、接管定位、防止焊接变形、防止焊接裂纹等工序分析的基础上,提出相应的质量控制措施和对策。成功地完成全密度反应器的现场制作,这为我国大型压力容器或同类型的全密度大型反应器的现场组焊提供借鉴。     

聚乙烯,聚氯乙烯薄膜在冷冲压拉深工艺中的应用

结合生产工艺,本文介绍了聚乙烯(PE)、聚氯乙烯(PVC)薄膜在拉深工艺中的应用,分析了聚合物薄膜的摩擦性能,润滑机理,重点论述了PE,PVC薄膜在小型单缸柴油机油底壳拉深工艺中的润滑作用,结果表明固体润滑剂具有比油脂润滑剂更优越的性能,同时指出,聚乙烯、聚氯乙烯等聚合物自润滑薄膜在金属塑性加工工艺中具有广泛的应用价值。     

聚乙二醇(600)磷酸酯抗磨添加剂的合成研究

合成了聚乙二醇(600)磷酸酯,讨论了催化剂用量及投料方式、物料比、反应温度及反应时间对反应结果的影响,确定了最佳反应条件.催化剂用量为0.2%～0.3%,催化剂在高速搅拌下采用分批加料方式,在温度100 ℃,反应时间3 h,物料比为3∶1的条件下,酯化率达到了93.8%.     

微波扫描法检测聚乙烯管道热熔接头缺陷初探

以聚乙烯管道热熔接头为检测对象,使用微波扫描的方法检测热熔接头中不同类型的缺陷.首先对无缺陷的热熔接头进行微波扫描检测,得到的扫描图像作为参考图像.然后对含有裂纹、冷焊等不同缺陷的聚乙烯管道热熔接头进行微波扫描检测,得到具有不同特征的扫描图像.对这些扫描图像进行分析可以判别缺陷的类型.最后,利用拉伸力学测试的结果,初步验证了微波扫描方法对聚乙烯管道热熔接头缺陷检测的有效性.