Application of Semi-Hertzian Approach to Predict the Dynamic Behavior of Railway Vehicles Through a Wear Evolution Model

Wear prediction due to the wheel-rail interaction in a railway vehicle has a significant role in the view of running stability (critical speed), dynamic performance and maintenance scheduling. In this article, we have focused on the estimation of wear distribution on the wheel profile through co-simulation between the vehicle and the wear evolution models, built in the multi-body simulation (MBS) software ADAMS (VI-Rail) and MATLAB environments, respectively. As the shape of the contact patches varies from elliptical to non-elliptical depending upon the contact patch location on the rail and the wheel, the contact forces/stresses are calculated by using a combined formulation of semi-Hertzian approach with modified FASTSIM. The wear distribution is obtained using Archard’s wear model. The wheel profiles are updated after calculating the wear depth for a particular distance travelled by the vehicle. The dynamic behavior of the vehicle with the worn wheel profile is utilized to predict additional wear during a further fixed distance of travel and this profile updating and dynamic simulation process is repeated. The vehicle’s dynamic performance and passenger comfort are evaluated for various levels of wheel wear.     

汽车平顺性仿真模型及试验研究

目前在汽车平顺性仿真研究中,没有考虑车身的弹性变形对整车动态性能的影响,导致仿真结果与试验结果存在差别。在ADAMS/Car模块中分别建立了整车多刚体模型和整车刚弹耦合模型,并进行了随机路面输入下的平顺性仿真试验和评价。实车道路试验验证了模型的正确性和合理性。研究结论可为汽车平顺性的研究和优化提供参考和借鉴。     

基于随机路面的空气悬架平顺性研究

将空气弹簧的刚度特性曲线编写XML文件,与机械系统仿真分析软件ADAMS结合,建立了空气悬架的客车模型,并根据相关法规在ADAMS/Car Ride环境中对虚拟样机进行平顺性仿真,仿真结果在ADAMS/postprocessor环境中进行处理,给出了一种求得平顺性评价指标较为简便的方法。结果表明分析样车的悬架系统设计合理,虽舒适性随车速提高及路面等级的下降,加权加速度均方根值呈增大趋势,但仍然能保持在主观评价的舒适界限之内。     

铁路客车间壁弹性减振技术研究

本文介绍一种对铁路客车间壁结构的振动控制方法,通过采用仿真、现车测试和实验室测试相结合的手段,在间壁减振器安装结构基础上,对减振器自身参数进行优化和安装结构的优化设计等方法实现自车体至车内内饰的振动衰减,进一步降低车内噪声振动水平和提高车内舒适度度.     

CRH3型动车组紧急制动安全回路研究

紧急制动安全回路基于传统的接触器电路设计,独立于列车控制系统,可以进一步提高列车的安全性和可控性.本文主要针对CRH3型动车组紧急制动安全回路的触发条件、工作原理及工作模式进行了研究,希望为推动新的紧急制动安全回路策略提供设计依据.     

核燃料组件铁路运输容器系统在纵向冲击下的安全性分析

针对铁路车辆系统在编组、制动等工况下产生的纵向冲击 ,推导了车辆之间的纵向作用力和描述冲击特性的加速度。利用ADAMS软件建立了核燃料组件铁路运输容器系统的仿真模型。对燃料组件运输容器系统在运输过程中受来自铁道车辆的纵向冲击情况下的振动安全性进行了分析 ,讨论了纵向冲击作用对捆绑涤纶丝带的拉力和燃料组件纵向加速度的影响。     

汽车乘员舱安全性与舒适性多学科设计优化

概念设计阶段汽车乘员舱的安全性和舒适性设计是关键任务,两者具有耦合效应,将多学科设计优化运用到乘员舱的设计中实现两个学科的并行设计。针对某款车的乘员舱布置,在该车100%正面碰撞试验基础上,通过乘员损伤分析软件建立该车的正面碰撞乘员约束系统模型并对模型进行验证用于评估其安全性;同时也基于关节强度的概念建立乘员舒适性模型。将多学科设计优化运用到乘员舱的设计中,避免了传统设计方法对安全性和舒适性的单独优化,实现了两个学科的并行设计,缩短了开发周期,最大化了乘员舱的整体性能。为提高计算效率,通过试验设计构建乘员约束系统的Kriging近似模型用于代替仿真模型。结果表明,该方法在较好地满足乘员安全性的同时提高了乘员的乘坐舒适性,在乘员舱布置方面具有较强的工程实用性。     

A new model in rail-vehicles dynamics considering nonlinear suspension components behavior

In this paper, a complete four axle rail vehicle model is addressed with 70 degrees of freedom (DOFs) including a carbody, two bogies, and four axels. In order to include the effects of the track irregularities in vehicle dynamics behavior, a simplified track model is proposed and it is validated by some experimental data and test results. As the performance of the suspension components, especially for air springs, have significant effects on rail-vehicle dynamics and ride comfort of passengers, a complete nonlinear thermo-dynamical air spring model, which is a combination of two different models, is introduced and implemented in the complete rail-vehicle dynamics. By implementing Presthus formulation [Derivation of air spring model parameters for train simulation. Master dissertation, Department of Applied Physics and Mechanical Engineering, Division of Fluid Mechanics, LULEA University, 2002], the thermo-dynamical parameters of air spring are estimated and then they are tuned based on the experimental data. The results of the complete rail-vehicle field tests, show remarkable agreement between proposed model and test data.     

Modelling and analysis of vehicle-structure-road coupled interaction considering structural flexibility,vehicle parameters and road roughness

To determine the dynamic forces acting on vehicle components a vehicle-structure-road interaction is considered. Coupled interaction was modelled using a flexible bridge-like thin beam structure with four and six Degree of freedom (DOF) half car models. In addition to the flexible structure, the road conditions were added to the model as random and non-random surface irregularities. A coupled equation of motion of the whole system was derived using Lagrange equations, and converted to a first-order state-space equation and then solved using the fourth-order Runge-Kutta method. Besides the dynamic forces, the effects of the vehicle speed, bridge flexibility, tire stiffness, random or non-random road irregularities on the passenger comfort are widely investigated. The results obtained were compared by several early VBI (Vehicle-bridge-interaction) studies in the literature and proved accurate with a 5 % difference.     

军用履带车辆平顺性虚拟样机试验研究

基于多体动力学仿真软件ADAMS建立了履带车辆虚拟样机模型,对车辆的平顺性进行了仿真研究,并与实验结果进行了比较,结果表明,该仿真模型能够对履带车辆的平顺性进行准确地分析与预测.     

基于磁流变阻尼器的铁道车辆结构振动半主动控制

在建立铁道车辆柔刚体系统垂直动力学模型的基础上,应用独立模态空间控制理论和最优控制理论,对影响车辆垂直运行平稳性的车体低阶弯曲结构振动和浮沉、点头等刚体振动进行控制。根据铁道车辆悬挂系统的特点,提出采用磁流变阻尼器作为作动器,以降低车体垂直加速度进而改善运行平稳性为目标的半主动控制策略,来实现在性能改善和能量消耗之间的协调,在ADAMS和Matlab/Simulink?环境下,应用机械系统和控制系统联合仿真技术,对采用半主动控制策略的整车性能进行仿真研究。仿真结果显示该半主动控制策略能较好地抑制车体第一阶弯曲模态的结构振动,并可改善车辆运行平稳性,针对铁道车辆系统的磁流变阻尼器在设计上是可行的。     

机车车辆动力性能的动态模拟

对实物试验、计算机仿真和混合模拟为基本形式的动态模拟技术进行分析,并列举各种动态模拟技术在铁路机车车辆研制过程中的应用。提出用滚轮代替钢轨,利用滚轮的上下和左右运动模拟轨道不平顺,采用滚轮差速模拟曲线,从而实现机车车辆运行的动态模拟。根据轨道不平顺的定义,给出线路状态和试验台滚轮的关系,给出机车车辆运行动态模拟试验台的设计方案。对西南交通大学牵引动力国家重点实验室的机车车辆整车滚动振动试验台的结构和功能进行系统介绍。根据机车车辆动力学性能——运动稳定性、运行平稳性和曲线通过性能的台架试验方法,通过台架试验和线路运行的理论分析,得到相应的试验误差,验证了机车车辆台架试验的可行性和合理性。     

Urban rail track condition monitoring based on in-service vehicle acceleration measurements

Condition monitoring of railway tracks is essential in ensuring the safety of railway systems. Traditional track recording vehicles (TRV) can only carry out the track inspection in the midnight after all the service vehicles are off duty. One track line can be inspected only once or less in a month. The severe track condition degradation cannot be detected timely and there is potential safety hazard for the railway system. Therefore, the track condition monitoring based on in-service vehicle has been paid more attention in the recent years. In this paper, the track condition monitoring based on the bogie and car body acceleration measurements is presented. The track alignment information which can be derived from the bogie and car body sensor is investigated by using a mathematical model and the frequency response analysis. The track irregularities can be estimated by using the bogie and the car body acceleration sensors. The acceleration signals are preprocessing with a DC filter and a low pass filter. After that, the track alignments are obtained by double integrating the signals. Field tests are carried out in Shang Hai metro Line 1 for demonstrating the effectiveness of the proposed track inspection system.     

汽车随机路面输入平顺性仿真分析

以某多功能商务车为研究对象,利用ADAMS软件建立了车辆多刚体动力学模型,并进行了随机路面输入下的汽车平顺性仿真。仿真结果和试验结果相当吻合,同时也验证了整车建模的正确性和准确性。其研究结果为虚拟样机技术在车辆工程中的实际应用提供了参考;为进一步对实例车辆做其他设计分析打下了良好的基础。     

基于ADAMS的载货汽车平顺性仿真与优化

以多体动力学软件ADAMS为基础,针对车辆行驶平顺性的优化设计进行了二次开发,所设计的平台对整车模型主要减震部件的刚度和阻尼进行参数化设计,并利用二次开发后的ADAMS软件对某车型进行了分析与优化,根据优化结果对该车型进行了改进,实际验证了此次二次开发的正确性。     

应用ADAMS软件研究整车平顺性中几个问题的探讨

应用机械系统分析软件ADAMS建模研究整车非线性随机振动，模型的自由度达1997个。利用伪白噪声法产生伪随机序列模拟路面不平度；利用BEAM梁建立了钢板弹簧主副簧仿真模型，讨论了主副簧约束问题。     

某型商用车司机座椅振动特性研究与优化

对某型商用车中的固定式座椅进行了传递特性研究,利用苏试电动振动台对座椅传递特性进行了试验,并建立了ADAMS动力学模型,利用试验数据验证了模型的准确性,并在此基础上进行了座垫刚度阻尼的优化,仿真表明优化后的座椅能在一定程度上改善座椅舒适度.     

超轻度混合动力传动系统建模和仿真

分析超轻度混合动力汽车及其传动系统,采用键合图理论,建立了超轻度混合动力汽车高速纯无级调速工况下的整车传动系统键合图模型,列出高速挡传动系统的状态方程。建立整车控制仿真模型,制定高速挡控制策略并进行了仿真分析。     

车轮磨耗计算模型及其数值方法

综述国内外车轮磨耗理论模型及其数值方法,提出基于车辆轨道垂、横向耦合动力学、轮轨滚动接触力学和材料摩擦磨耗模型为一体的车轮磨损计算模型, 并发展相应的数值方法。模型中车辆结构和钢轨下部结构被简化成等效质量、弹簧和阻尼系统, 而钢轨用Euler 梁代替, 并考虑它的垂向、横向弯曲变形和扭转变形。利用修改的KALKER三维弹性体非Hertz 滚动接触理论和相应的数值方法计算轮轨蠕滑力和滑动量等参量;根据Archard材料磨损模型计算车轮的磨耗深度。利用该模型和相应的数值方法分析不同曲线半径情况下车轮的磨损情况,结果表明该模型可以较好地模拟车轮磨损的演化过程。给出列车通过曲线半径为350 m时车轮的磨损情况。数值结果表明,每个转向架下前轮对比后轮对磨耗严重,外轨上的车轮比内轨上的车轮磨耗严重。     

基于ADAMS模型的履带车辆半主动悬挂自适应控制

建立了某履带车辆ADAMS整车模型。搭建了控制算法MATLAB与实体模型ADAMS之间的联合仿真接口。提出了采用模糊控制器调整PID调节器参数实现基于ADAMS建模的整车半主动悬挂控制策略。用动行程及其变化率作为模糊控制器的输入,通过模糊控制器的输出动态调整PID调节器的参数,形成了车辆半主动悬挂自适应控制系统。仿真研究表明,该自适应控制系统能够有效协调加速度和动行程在不同频段的矛盾,明显改善履带车辆行驶的平顺性。