篦齿封严装置减振方法研究及减振装置设计

本文研究了用于篦齿封严装置的干摩擦式阻尼减振器的减振原理,采用篦齿封严装置气弹稳定性分析方法,分别研究了用于篦齿封严装置的阻尼环和阻尼套筒的减振效果,并在此基础上提出了阻尼减振器的工程设计方法。研究表明,干摩擦式阻尼减振器可以有效地提高篦齿封严装置的气动弹性稳定性。     

机场跑道摩擦系数测试试验数据分析

介绍了自行研制的机场跑道摩擦系数测试车的测量原理与系统组成。以在车体后桥部位安装的专用测量轮为测试栽体，测量该测量轮所受的垂直正压力和水平摩擦力，计算跑道的摩擦系数。采用对比试验方法．进行了本车与瑞典Safegate跑道摩擦系数测试车的测量试验，并对本车和瑞典Safegate测试车的测量误差和测量数据的稳定性、重复性、相关性等进行了统计分析。     

我国遭遇国际贸易摩擦的必然性及启示

经济的高速增长和对外开放政策的执行，使得我国的对外贸易量逐年稳步上升，然而在对外贸易迅速发展的同时，中国也进入了国际贸易摩擦的高峰期。对此，一方面，我们必须清楚认识到摩擦产生的必然因素，清醒地从容面对摩擦；另一方面，要积极主动地与国际接轨，运用合理手段处理好摩擦，更好地把握国际贸易摩擦对我国外贸发展的启示．     

GH4169高温合金惯性摩擦焊接头动态再结晶过程

当温度、应变、应变速率达到一定条件时 ,GH4 16 9镍基高温合金在惯性摩擦焊接过程中易发生动态再结晶。本文研究结果表明 ,由于GH4 16 9合金惯性摩擦焊接时间很短 ,动态再结晶进行得相当充分 ,而动态回复不足 ,在动态再结晶的过程中还可以看到有些结晶过程还处于形核阶段 ,这是惯性摩擦焊接头产生细晶乃至超细晶的根本原因     

粉末高温合金FGH96惯性摩擦焊接头常温力学性能分析

第二代粉末高温合金FGH96是采用损伤容限设计思想研制的新型粉末高温合金,是当前750℃工作条件下满足高推比、高燃效发动机使用要求的涡轮盘、环形件和其他热端部件的理想材料.结合FGH96惯性摩擦焊接头的组织特征和强化相γ′数量分析接头的显微硬度和常温拉伸性能.结果表明,FGH96惯性摩擦焊接头具有良好的常温力学性能.     

计及摩擦时层合板孔内轴销的应力和位移分析

为解决含圆孔层合板在孔内轴销加载下的孔边应力问题，提出一个计及接触摩擦效应的弹性轴销模型，摩擦系数假设为沿接边界按正弦规律变化，在此基础上，采用弹性理论的一般方法，分析了轴销的应力和位移，为有效地解决有载孔层合板孔边应力问题提供了解析基础。     

线性摩擦焊设备的振动测量和分析

针对线性摩擦焊设备焊接误差较大的问题，采用参数记录系统和加速度传感器测量了设备多个部位的振动幅度，并设计了高刚度顶锻滑台，为线性摩擦焊设备优化结构设计、减小振动以提高焊接精度提供了参考。     

TC4钛合金静止轴肩和传统搅拌摩擦焊的温度场对比

基于有限元软件ABAQUS对6mm厚的TC4钛合金传统及静止轴肩搅拌摩擦焊温度场进行了有限元模拟.结果表明,对比传统搅拌摩擦焊接,静止轴肩搅拌摩擦焊接具有较小的高温区,前进方向上具有较大的温度梯度,厚度方向上呈现柱状椭球形分布,上、下表面温度峰值差异较小,具有重叠性较好的热循环曲线.     

Stability analysis of an aeroelastic system with friction

In this paper, harmonic balance method, exact formulation and numerical simulation method are adopted to study the effects of different friction stiffness on the stability of 1.5 degrees of freedom aeroelastic system. On this basis, the expressions of input energy and dissipated energy are deduced, and the energy method is used to reveal the mechanisms of the stable boundary and unstable boundary existing in the system and the effects of different friction stiffness on the stability of the system. Studies have shown that the stability region and the critical aerodynamic damping ratio of the system rise with the increase of the friction stiffness, while the friction stiffness has little effect on the stability boundary. In the analysis of the stability of system, the results of harmonic balance method, exact formulation and Newmark of numerical simulation method are in good agreement. Compared with exact formulation and numerical simulation method, the concept and conclusion of harmonic balance method are simple in the system stability analysis.     

Morphology and Frictional Characteristics Under Electrical Currents of Al203/Cu Composites Prepared by Internal Oxidation

Two AhO3/Cu composites containing 0.24 wt.% A1203 and 0.60 wt.% A1203 separately are prepared by internal oxidation.Effectsof sliding speed and pressure on the fi-ictional characteristics of the composites and copper against brass are investigated and compared.The changes in morphology of the sliding surface and subsurface are examined with scanning electron microscope (SEM) and energy dispersive X-ray spectrum (EDS).The results show that the wear resistance of the AI203/Cu composites is superior to that of copperunder the same conditions.Under a given electrical current,the wear rate of AI203/Cu composites decreases as the AleO3-content increases.However,the wear rates of the Al203/Cu composites and copper increase as the sliding speed and pressure increase under drysliding condition.The main wear mechanisms for AleO3/Cu composites are of abrasion and adhesion;for copper,it is adhesion,although wear by oxidation and electrical erosion can also be observed as the speed and pressure rise.