Tyre rolling kinematics and prediction of tyre forces and moments: part I – theory and method

A new method to describe tyre rolling kinematics and how to calculate tyre forces and moments is presented. The Lagrange–Euler method is used to calculate the velocity and contact deformation of a tyre structure under large deformation. The calculation of structure deformation is based on the Lagrange method, while the Euler method is used to analyse the deformation and forces in the contact area. The method to predict tyre forces and moments is built using kinematic theory and nonlinear finite element analysis. A detailed analysis of the tyre tangential contact velocity and the relationships between contact forces, contact areas, lateral forces, and yaw and camber angles has been performed for specific tyres. Research on the parametric sensitivity of tyre lateral forces and self-aligning torque on tread stiffness and friction coefficients is carried out in the second part of this paper.     

Tyre rolling kinematics and prediction of tyre forces and moments: part II – simulation and experiment

There are two aims for the second part of this paper: verifying the theory presented in the first part through parameter variation and comparison between simulation and experiment, and to study the effect of the belt structure on the cornering properties of radial tyres. Research has been carried out with a passenger car radial tyre and two different kinds of truck or bus radial tyres using both simulation and experiment. This second part of the paper shows that belt structure plays an important role in the generation of tyre forces and moments in addition to the effects of the tread stiffness and friction coefficients. The theory and method presented in this paper opens a new robust way to predict the tyre forces and moments from the tyre design and provides a reliable model for a generation mechanism.     

山区高速公路坡面荷载的动态效应与实测研究

为了获取公路陡坡路段荷载对路面结构的动态效应,为理论计算分析和试验分析提供可靠的参数,利用自主开发的轮胎对地压力动态分布实时测量装置,进行了不同车型、不同载重、不同车速和不同纵坡条件下坡面轮胎接地压力的动态测量,得出了不同速度下坡面轮胎接地压力的分布及其变化规律。结果表明,高速运动状态下,重载货车轮胎接地形状近似于矩形,车速越高接地形状接近矩形的相似程度愈高;随着车速提高,接地压力的分布形式从凸起型分布逐渐向鞍型分布演变,接地压力峰值逐渐减小;运动状态下,车辆轮胎接地压力在行进方向上呈半正弦波分布,在横向上表现为非均匀分布。     

汽车继电器触点寿命分析及保护措施

通过理论分析和实际测试结合的方法,论证汽车负载特性,对汽车继电器工作情况及继电器触点的转移现象进行理论分析,并针对汽车负载的特性提出一些保护触点的措施。     

水下航行器凸轮发动机凸轮机构的接触应力分析

水下航行器凸轮发动机的凸轮机构是其主要受力部件,在设计过程中必须进行强度校核。通过对凸轮和圆柱滚轮的接触情况进行分析,运用微分几何理论导出了凸轮的工作曲面方程和接触点的诱导法曲率模型,采用弹性力学中的赫兹理论,建立了凸轮机构的接触应力模型,并进行了算例分析。仿真模型能准确地计算水下航行器凸轮发动机凸轮机构的接触应力,可为其设计和参数的选择提供理论依据。     

地铁车辆受流器与接触轨间的摩擦试验分析

介绍了北京地铁为解决受流器滑块磨损严重的问题,利用自主开发的摩擦试验机模拟不同材质的受流器滑块与接触轨之间摩擦的情况,并对试验结果进行分析比较,找出了较好的地铁车辆受流器滑块方案。     

接触网全补偿链形悬挂5跨锚段关节过渡跨吊弦计算模型的探讨

通过引入当量线密度的概念,建立了接触网全补偿弹性链形悬挂及全补偿简单链形悬挂的5跨锚段关节屋脊过渡跨吊弦的计算模型     

Assessment of a semi-Hertzian method for determination of wheel-rail contact patch

Wheel-rail contact calculations are essential for simulating railway vehicle dynamic behavior. Currently, these simulations usually use the Hertz contact theory to calculate normal forces and Kalker's 'FASTSIM' program to evaluate tangential stresses. Since 1996, new methods called semi-Hertzian have appeared: 5, 7 (STRIPES). These methods attempt to estimate the non-elliptical contact patches with a discrete extension of the Hertz theory. As a continuation of 2, a validation of the STRIPES method for normal problem computing on three test cases is proposed in this article. The test cases do not fulfill the hypothesis required for the Hertz theory. Then, the Kalker's FASTSIM algorithm is adapted to STRIPES patch calculus to perform tangential forces computation. This adaptation is assessed using Kalker's CONTACT algorithm.     

承力索张力对弓网受流质量影响研究

首先建立了弓网动力学模型。在其余参数均不变的基础上,研究了承力索张力对弓网受流质量的影响,并对各个工况进行了仿真。仿真结果表明,增大承力索张力可以减小弹性不均匀系数,增大反射系数,且接触压力与振幅呈不规则变化趋势。最后提出了几个相应的建议。     

单、双层衬砌隧道的非线性有限元分析

采用一种接触磨擦单元并利用广泛应用于岩土工程分析的 Mohr- Coulomb塑性准则对同一隧道采用不同的衬砌类型的结构性能进行了比较分析 ,取得了一些有意义的结果