车轮荷载下土壤静力学特性分析

利用有限元软件ANSYS建立三维有限元模型,模拟车轮和土壤的静态接触,进行非线性有限元分析,研究车轮荷载下土壤的静力学特性。采用基于Drucker-Prager的弹塑性模型来模拟真实土壤,并考虑摩擦作用。分别采用刚性轮模型和超弹性轮胎模型模拟车轮,并将2种情况进行对比。结果表明：在车轮荷载作用下,土壤的竖向位移和等效应力在轮胎与土壤接触的区域最大;土壤的竖向位移和等效应力随土壤深度的增加而减小;土体在刚性轮作用下的变形和应力要远大于其在超弹性轮作用下的值,表明虽然刚性轮几何形状简单,模型设置容易,但是与超弹性轮胎模型相比,这种模拟精确度低。     

重载交通对路面使用性能的影响分析

该文通过对一条高速公路的交通量调查与分析,揭示了目前道路早期破坏的重要因素是交通量超过了设计次数。同时通过室内的车辙试验和APA试验,分析了高轮压对路面抗车辙能力的影响。研究结果建议,在今后道路设计中要加强交通量预测,道路运营中要加强对高胎压车辆的管理。     

轮胎压路机压实沥青混合料原理分析

沥青混合料的压实是影响沥青路面性能的重要因素之一。根据轮胎压路机的压实过程,结合有效应力和固结原理并结合力学原理,分析轮胎压路机的压实机理及揉搓作用,提出轮胎压路机在对沥青混合料压实中的使用注意事项。     

基于AHP的轮胎回收利用综合评价

废、旧轮胎已成为我国新的主要固体废弃物污染源,利用科学的方法分析影响轮胎回收利用的因素,为轮胎回收利用决策者提供合理的依据,对促进发展循环经济,建立集约型社会有重大作用。通过对影响废旧轮胎回收的相关因素分析研究,归纳总结出影响回收利用的指标体系,利用层次分析法(AHP)确定各因素的相对权重,并针对评价结果提出了具体方案建议。     

轮载下车辆甲板塑性承载能力利用程度研究

目前针对车辆甲板,各船级社的板厚设计已经考虑了塑性承载能力,但塑性承载能力的利用程度并没有明确说明.本文采用数值模拟方法,依据各船级社规范,选取有代表性的车辆甲板货物载荷进行板厚设计,考察了设计板厚下板格的应力水平及离散程度;结果表明计算板格最大应力均值都大于弹性许用应力,而且超过了材料的屈服应力.最后从应力水平角度出发,分析了车辆甲板考虑塑性承载能力的程度.     

发动机自动熄火故障的排除

轮胎式起重机"油改电"改造后,发动机经常自动熄火,必须予以解决。分析故障发生原因,阐述故障排除方法,效果较好。     

Straight-ahead running of road vehicles – analytical formulae including full tyre characteristics

ABSTRACT

During straight-ahead running, the longitudinal axis of road vehicles, notably cars, is not parallel to road axis. This occurrence is general and is due both to road cross slope (road banking) and to tyre characteristics, particularly ply-steer and conicity. In order to describe such a phenomenon, the paper develops a new and relatively simple analytical model. Despite the model is linear, the solution which is provided is exact, since straight-ahead motion occurs with small angles and both the elastokinematics of suspension system and tyre characteristics can be modelled by linearised equations. The Handling Diagram theory is updated and completed by introducing the actual shifts of tyre characteristics. The validation of the analytical expressions is performed by using a MSC Adams^TM full model of a car. A subjective-objective experimental test campaign provides preliminary substantiation of the ability of the derived formulae to describe tyre performance. By means of the unreferenced analytical formulae developed in the paper, we allow, given the vehicle, the proper tyre design specification and vice-versa. In particular, a formula is given to make null the steering torque during straight-ahead driving. The derived analytical formulae may provide a sound understanding of the straight-ahead running of road vehicles.     

纯电动汽车轮胎磨损关键影响因素研究

木文在分析纯电动车汽车不同于传统燃油车对于轮胎磨损关键因素的基础上,对纯电动车汽车轮胎磨损影响因素进行了试验验证。试验针对栽荷及动力系统两个因素采用控制单一变量法进行轮胎道路磨损试验,并通过对试验路线优化及驾驶员驾驶习惯的约束,使得测试结果更加准确及客观。最后对测试完成之后的轮胎花纹形态、轮胎花纹深度及轮胎预计里程寿命进行了详细数据分析。     

Tyre friction behaviour under abrupt wheel torque transients on slippery road surfaces: experimental analysis and modelling

The paper shows that, during abrupt wheel torque transients for ice surface and low vehicle speeds, the tyre can develop significantly larger longitudinal force than the peak value of the tyre static curve. This so-called dynamic tyre friction potential (DTFP) effect has many influencing factors such as the rate of change of the wheel torque, the vehicle speed, and the tyre dwell time. The paper presents a detailed analysis of the DTFP behaviour based on the experimental data collected by using an in-wheel motor-based tyre test vehicle. The analysis results and an insight into the brush structure of a tyre model lead to the hypothesis that the different influencing factors may be predominantly explained by the bristle dwell time (BDT) effect. Following this hypothesis, the LuGre model of the tyre friction dynamics is extended with a physical BDT sub-model. The experimental validation results show that the proposed model can accurately capture the low-speed tyre–ice friction behaviour during abrupt wheel torque transients.     

Estimation of the tyre–road maximum friction coefficient and slip slope based on a novel tyre model

In this article, a new approach to estimate the vehicle tyre forces, tyre–road maximum friction coefficient, and slip slope is presented. Contrary to the majority of the previous work on this subject, a new tyre model for the estimation of the tyre–road interface characterisation is proposed. First, the tyre model is built and compared with those of Pacejka, Dugoff, and one other tyre model. Then, based on a vehicle model that uses four degrees of freedom, an extended Kalman filter (EKF) method is designed to estimate the vehicle motion and tyre forces. The shortcomings of force estimation are discussed in this article. Based on the proposed tyre model and the improved force measurements, another EKF is implemented to estimate the tyre model parameters, including the maximum friction coefficient, slip slope, etc. The tyre forces are accurately obtained simultaneously. Finally, very promising results have been achieved for pure acceleration/braking for varying road conditions, both in pure steering and combined manoeuvre simulations.