A study on the stability of a motorcycle wheel–swingarm suspension with chain transmission

The present study describes a possible driving mechanism for a self-excited oscillation observed in motorcycle dynamics, often referred to as chatter. This phenomenon, affecting the performance of road racing motorcycles, has been simulated in straight running braking manoeuvres with multibody motorcycle models. It involves rear suspension bounce and driveline oscillation in the frequency range between 17 and 22?Hz. A simplified model of a motorcycle rear suspension with chain transmission is proposed and its stability in equilibrium configurations is studied via eigenvalue analysis. The sensitivity with respect to all its governing parameters is analysed by means of stability maps and the self-excitation mechanism is explained with the aid of energy balance analysis and phase diagrams. It is found that the key role for the instability onset is played by the gradient of the nonlinear characteristic slip function of the tyre.     

严格监理 认真把关 创精品工程

阐述在创建治理营口港四期54#～56#泊位码头工程质量通病示范项目工作中,监理公司的具体作法和经验。     

大圆筒重力式码头漏砂的原因分析和处理

基于受力条件好、投资省、便于施工等明显的优越性，大圆筒结构在南方许多港口广泛应用。针对大圆筒结构常存在的圆筒间接缝漏砂的问题，提出了一种简单易行的处理方法。     

二系螺旋弹簧刚度计算

采用有限元计算方法,对机车车辆二系螺旋弹簧的刚度进行计算。结果表明,弹簧在横向载荷作用下,由于上端移动,垂向载荷的作用位置随之发生变化,在弹簧两端切口的影响下,弹簧的受力状态发生变化,垂向刚度随载荷的变化而变化比较明显,横向刚度与所施加的横向载荷方向有关。     

“南海挑战号”半潜平台改造方案研究

随着开发形势的发展，流花油田“南海挑战号”半潜平台现有的4台发电机越来越不满足电力供应要求，因而必须增加新的发电机。但由于增加电机及相应辅机、结构等较重，超过规范要求。“南海挑战号”必须停产做倾斜试验，这会对业主造成很大的经济损失。针对电站扩容项目，通过数值计算方法精确得到平台改造后的重量重心，平台完整稳性和破舱稳性均满足船级社规范中关于稳性的要求，避免了停产做倾斜试验等问题。     

基于刚度退化的框-剪结构受力性能研究

根据模型试验数据确定各变形阶段框架与剪力墙的实际刚度,针对4种典型工况,分别采用框架与剪力墙刚度退化系数计算刚度退化后的各楼层刚度,再沿结构高度方向加权平均得到结构真实刚度。基于协同工作原理提出一种考虑结构刚度退化计算框-剪结构的适用方法,通过算例分析了结构的受力性能。研究结果表明:考虑结构刚度退化后,结构自振周期增加,刚度减少,侧移增大,总框架承担总剪力的比例增加,《规范》对框架承担剪力的调整是有必要的。     

CW-2系列转向架轴箱定位节点垂向刚度研究

介绍了CW—2系列转向架运用中出现的故障,结合轴箱定位结构分析了定位节点刚度较大带来的问题,并得出定位节点垂向刚度较大也是导致转向架出现较多运营可靠性问题的初步结论。利用动力学分析软件,计算了不同节点定位刚度对轮轨垂向力、构架垂向振动、节点处动态垂向力和车辆其他动力学性能的影响趋势,以TGV高速列车的2种转向架的试验比较进行了验证。     

Assessment of the influence of the elastic properties of rail vehicle suspensions on safety,ride quality and track fatigue

A sensitivity analysis has been performed to assess the influence of the elastic properties of railway vehicle suspensions on the vehicle dynamic behaviour. To do this, 144 dynamic simulations were performed modifying, one at a time, the stiffness and damping coefficients, of the primary and secondary suspensions. Three values were assigned to each parameter, corresponding to the percentiles 10, 50 and 90 of a data set stored in a database of railway vehicles. After processing the results of these simulations, the analysed parameters were sorted by increasing influence. It was also found which of these parameters could be estimated with a lesser degree of accuracy in future simulations without appreciably affecting the simulation results. In general terms, it was concluded that the highest influences were found for the longitudinal stiffness and the lateral stiffness of the primary suspension, and the lowest influences for the vertical stiffness and the vertical damping of the primary suspension, with the parameters of the secondary suspension showing intermediate influences between them.     

客运专线无砟轨道系统设计

根据我国客运专线的工程特点,无砟轨道结构选型应遵循施工性、维护性、动力性、适应性和经济性的5个基本原则,并给出2类无砟轨道的性能.在研究确定无砟轨道设计理论和原则的基础上,建议设计轮重取静轮重的3倍、疲劳检算轮重取静轮重的1.5倍.板式无砟轨道不同弹性模量的砂浆垫层对轨下基础刚度的影响不同,建议研发新型填充层材料.合理确定无砟轨道的弹性,建议轨下基础刚度的合理范围为20～30kN·mm-1.通过定期打磨钢轨和钢轨无缝化,降低噪音;通过降低轨道刚度、提高轨道参振质量,降低线路下部结构物的振动.无砟轨道的设计寿命应为60年,为此应制定相应的维修标准和管理办法.     

ANSYS在东风EQ140汽车车架刚度分析中的应用

应用ANSYS软件,完成了东风EQ140型汽车车架的刚度分析过程。通过建模、加载、解算及后处理等一系列步骤获得车架的扭转变形及应力,揭示出车架横梁在后桥支撑点存在扭转变形最大的问题,为车架的优化设计提供了重要依据。