减振型三叉式万向联轴器结构及其疲劳寿命分析

为了提高动力传动系统中三叉式万向联轴器的工作可靠性,根据三叉式万向联轴器工作时滑块组件上存在的周期性变化的径向载荷和轴向载荷,设计了橡胶减振型三叉式万向联轴器新型结构,并对其寿命进行预测。采用名义应力法,通过试验获得氟橡胶材料的S—N曲线,并对减振结构进行疲劳寿命有限元分析。结果表明减振型三叉式万向联轴器的最小疲劳循环次数为5.88×10⁶ 次,出现在氟橡胶减振元件处;由减振型万向联轴器运行的里程与循环次数的关系确定其寿命约为1.47×10⁶ km。研究结果可为联轴器在应用过程中的定期维修与更换提供理论依据。     

Fatigue life of a friction welded joint with a circular crack in the centre

This paper compares the calculated fatigue life with the tested life, for an embedded crack in the friction weld between two axially loaded rods. The initial crack is caused by lack of fusion in the centre of the friction weld. The radius for the initial circular crack is 5–6 mm. The stress intensity factors for the crack are calculated with the weight function method. It was found that a relatively high axial tensile residual stress must exist in the centre, to get the crack to grow sufficiently fast. An approximation for the residual stress distribution is used in the calculation. The calculation gives about 30% longer median lives than the fatigue tests. That might depend on uncertainties in material data and/or the fact that the tensile stress in the centre is higher than expected. The paper also shows that the integrals in the weight function method can be solved by a standard mathematics program.     

Effect of certain hardening treatments on friction and wear of metals

A new method of surface hardening of friction pair components is described. The method consists in the deposition on metal surfaces of finely dispersed composite structures obtained as a result of the formation of liquid eutectics at the metal-hardening phase interface followed by rapid cooling. Tests in vacuum showed that most wear resistant are finely dispersed boride coatings obtained by water quenching liquid eutectics.     

Study of the structurization kinetics in hardening dispersion systems by the internal friction method

An experimental study was made concerning changes in the internal friction in a disperse material during hardening and the effect of the initial solid-to-liquid contents ratio on the structurization process.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 24, No. 6, pp. 1068–1073, June, 1973.     

风速风向联合分布对结构风致疲劳寿命可靠性的影响

在进行结构风振疲劳寿命可靠性分析时,需要先求得建筑结构所在位置处的风速风向联合分布函数。本文首先对建筑结构附近两个气象站的气象资料进行统计分析,得到建筑结构位置处两个不同的风速风向联合分布函数,然后分析了不同的风速风向联合分布函数对一实际结构系统风振疲劳主要失效模式以及结构系统风振疲劳失效概率的影响。本文分析表明：用不同的风速风向联合分布函数计算风振疲劳寿命时会得到不同数目的主要失效模式,并且对结构系统的风振疲劳失效概率影响较大。     

三叉杆式万向联轴器的平均传动效率分析

为获得三叉杆式万向联轴器的平均传动效率，分析了三叉杆式万向联轴器输入轴上滑块的运动规律。首先，在滑块中心建立辅助坐标系，求出滑块在它与导向槽接触面中心相对导向槽的滑动速度以及滑块中心相对导向槽的滑动速度；其次，利用摩擦功率损失与速度的关系式，推导出三叉杆式万向联轴器的瞬时传动效率；最后，通过积分得出三叉杆式万向联轴器平均传动效率的表达式。通过分析发现：三叉杆式万向联轴器的平均传动效率与摩擦系数、输入轴与输出轴偏转角、叉杆半径和回转半径有关，平均传动效率随着摩擦系数、偏转角、叉杆半径的增大而减小，随着回转半径的增大而增大。该结果可为三叉杆式万向联轴器的设计和应用提供重要理论依据。     

电场对异种金属摩擦焊接头组织与性能的影响

研究了外加电场对T2紫铜和1Cr18Ni9Ti不锈钢摩擦焊接头焊合区的显微组织、主要合金元素的扩散区宽度以及接头力学性能的影响．结果表明，外加电场加快了焊合区金属的动态再结品进程，不同形式的电场对焊合区铜侧的组织形态与分布有不同的影响．在负电场(试件接电源负极)作用下，焊合区金厦发生的动态再结晶程度最大，品粒尺寸较大且分布均匀；交流电场使品粒尺寸略有减小．交流电场和负电场通过对金厦内部电子密度的影响，促进了焊接过程中焊缝区Cu、Pe和Cr的扩散，并提高了焊接接头扭转强度。