磁浮列车车轨耦合振动仿真研究

为了分析车轨道耦合振动过程中各因素的影响,建立了车体-悬浮架-轨道的简化动力学模型和动力学方程,利用数值方法研究了一节列车在静态悬浮过程中,整个车体与轨道耦合振动的垂向动力学行为.分析了轨道和车辆主要参数对振动的影响,并给出了仿真结果.仿真结果表明,轨道的抗弯刚度,长度,车轨质量比,以及车辆的悬浮刚度对于耦合振动影响较大;同时经过二系悬挂的衰减,车厢的振动较小.结论可供车辆悬浮控制器设计和轨道梁设计参考.     

基于GMM的轨道无线传感网络能量收集装置研究

随着轨道无线传感器网络技术的推广,改善无线传感器的供电问题显的刻不容缓。研究一种基于超磁致伸缩材料（GMM）的轨道振动能量收集器,将收集器安装于钢轨与轨道板之间,收集钢轨的振动能。建立车辆轨道垂向耦合模型,将钢轨垂向位移和支反力作为能量收集器的激振源。利用超磁致伸缩材料的维拉里效应,将振动能转换为电能。经过MATLAB理论分析,能量收集器大致能收集到能量大约237.1584 J。收集的电能足以解决无线传感器的供电问题。     

变摩擦力下板带轧机垂扭耦合振动控制技术

当前对板带轧机垂扭耦合振动的控制过程未考虑变摩擦力的影响，无法对振动特性进行准确分析，导致控制效果不理想。提出一种变摩擦力下基于振动摩擦模型的板带轧机垂扭耦合振动控制技术。将垂扭耦合振动参数作为输入向量，理想状态下变摩擦力作为输出向量，确定垂扭耦合振动参数。采用遗传算法对已确定的最优垂扭耦合振动参数进行辨识，构建振动摩擦模型，完成对垂扭耦合振动特性的准确分析，解决控制过程中的变摩擦力影响问题。利用振动摩擦模型对系统位移响应和频域响应振动特性进行控制，实现板带轧机垂扭耦合振动的控制。与传统控制技术进行对比，得出实验结果，所提控制技术控制精度可达98%，能够减小控制过程的变摩擦影响，可对振动特性进行准确地准确分析，大大提高了控制精度。     

钢轨波磨对地铁车辆动力学响应的影响

建立地铁车辆-轨道耦合动力学模型,将钢轨视为弹性离散点支撑的无限长Timoshenko梁,将实测钢轨短波波磨不平顺数据作为不平顺激励.通过数值计算得到在科隆蛋扣件线路上不平顺发展过程中车辆动力学响应的变化情况.随着短波波磨不平顺幅值的增大,轮对和转向架的横、垂向加速度以及轮轨横、垂向力均呈增大趋势,且受不平顺程度的影响较大.结果表明钢轨波磨主要影响车辆系统的垂向振动.     

基于轴距参数的载重汽车舒适性优化

针对传统刚度参数优化载重汽车舒适性时会降低承载能力的问题,由于轴距决定簧载质量分配,影响车身垂向振动加速度,并引起产生振动和冲击.为解决上述问题,提出用轴距参数优化舒适性的新方法.根据载重汽车动力学模型,建立轴距参数与整车舒适性能的数学关系.运用正交试验法,对比刚度、阻尼及轴距参数对舒适性的影响权重.采用平衡悬架车轴位置参数进行舒适性优化.进行时域和频域仿真结果表明,优化后整车舒适性能明显改善,轴荷分配更趋合理;车身垂向、俯仰、侧倾振动频域特性与经验值基本一致.研究结果说明载重汽车动力学模型正确,为优化提供了可行性.     

履带车辆乘座舒适性的建模与仿真

通过建立履带车辆"车辆-座椅-人"系统模型,并用MSC Adams软件仿真在典型路面条件下的履带车辆的垂向振动特性,对车辆乘座舒适性进行评价. 同时研究座椅的刚度、阻尼等动态参数对乘座舒适性的影响.     

刚柔耦合特种车辆越障行驶动力学分析及悬架优化

考虑炮管柔性,建立了某轮式特种车辆的刚柔耦合整车动力学模型,并与刚性车辆模型进行对比,分析了刚柔耦合建模对炮管响应的影响;然后计算了该车通过垂直凸台障碍路面的极限高度,分析了刚柔耦合特种车辆通过凸台障碍路面时的动力学特性.以车辆质心垂向加速度为优化目标,悬架刚度和阻尼为优化参数,对悬架进行优化.结果表明,炮管的弹性变形对炮口垂向和水平方向线位移、线速度和角速度的影响显著,建模中有必要考虑炮管柔性,以更准确地计算车辆响应;低速行驶、小的凸台高度,对减小车辆振动有利,在各种工况参数下炮管的垂向振动都比车体振动剧烈;单侧轮通过障碍可以减小路面对整车的冲击,双侧轮通过障碍可以提高车辆稳定性并减小炮管振动;悬架优化后整车和炮管的垂向加速度都明显降低,车辆平顺性得到有效改善.     

移动车辆桥梁系统中的振动能量获取

本文对移动车辆作用下桥梁系统的振动能量俘获进行了研究.将车辆模型简化为车轮--弹簧--阻尼器--簧上车身质量体系,桥梁简化为对边简支对边自由板模型,压电俘能结构采用粘贴有压电晶体材料的悬臂梁并在其末端附加一质量块.对于这个耦合动力学模型,首先,通过板壳振动理论推导出了移动车辆作用下板的运动微分方程;其次,根据欧拉伯努利梁振动理论和基尔霍夫第一定律得到了以桥梁振动响应作为激励的悬臂梁动力学--压电耦合方程;最后,对耦合运动微分方程进行了求解并对其数值模拟结果进行了分析.结果表明:采用设计的压电俘能结构可以有效地收集桥梁系统的振动能量,而压电装置的位置、压电梁的厚度、集中质量、车辆速度对压电俘能效率都有一定影响.     

基于降维状态观测器的轮轨力估计方法研究

轮轨作用力对车辆的运行品质及安全有重要影响;现有轮轨力测量方法采用了特制的测力轮对测量和轨道静态测量,其成本高、周期长、稳定性差;对现有轮轨力测量方法进行了研究,提出了降维状态观测器的方法观测轮轨力;建立单轮对车辆轨道垂向耦合模型,以车辆状态响应值与轨道激励作为降维状态观测器的输入;通过Matlab仿真计算,得出轮对振动位移的观测值快速收敛于仿真值,轮轨力有很好的吻合性;随着车辆速度增加振动位移收敛时间变长,轮轨力误差增大;结果表明,在一定条件下,此方法能够很好的地观测轮轨力的大小,为轮轨力的实时估计提供一种的新方法。     

基于视觉的车辆与轨道相对振动状态测量方法研究

车辆与轨道相对振动状态对轨道线形测量有重要影响;分析了传统检测车辆与轨道相对振动状态测量方法的缺陷,提出一种基于视觉的车轨相对振动状态测量方法,以轨道建立轨道坐标系,以车体建立车体坐标系;考虑相机镜头畸变,建立相机非线性模型,基于机器人手眼方法标定相机与车体,求解相机内外参数;依据车体运动姿态特征,推导基于双目机器视觉的车辆运动姿态偏移补偿计算方法;运用实验平台设计验证实验,通过计算所得的车体振动位移与真实值高度吻合,随着车速增加振动位移误差也随之增大,验证了该方法的正确性和可行性;提供一种车辆与轨道相对振动状态测量方法。     

简谐载荷作用下井字梁楼盖竖向振动控制

为研究某工业厂房井字梁楼盖在简谐载荷作用下的异常振动问题,根据现场动力特性测试结果,采用有限元软件Abaqus建立井字梁楼盖局部板-柱模型,通过增设调谐质量阻尼器(tuned mass damper,TMD)和布置隔振器对井字梁楼盖的竖向振动研究进行控制.结果 表明:增设TMD和布置隔振器均可以使楼盖竖向振动峰值加速度减小;选择4个质量比为2％的TMD布置在设备支座附近梁下,通过布局优选可以得到最优的减振方案;布置隔振器比增设TMD的减振效果更好,布置隔振器后各响应拾取点减振率大于80％.     

周期性冲击载荷作用下井字梁楼盖竖向振动的控制

针对周期性冲击载荷作用下井字梁楼盖异常振动问题,对某工业厂房井字梁楼盖进行现场动力特性测试,采用Abaqus软件建立局部楼盖有限元模型,研究周期性冲击载荷作用下井字梁楼盖的动力特性,并提出设置调谐质量阻尼器(tuned mass damper,TMD)、增设隔振支座等2种减振方案.结果 表明:4种不同TMD布置方式的减振效果不同,在设备4个支座处布置TMD的减振效果最佳;增设隔振支座后,采用有限元法得到各测点减振率为83.91％ ～88.80％.2种方案均能有效降低楼盖的竖向振动,可为结构振动控制提供参考.     

Influence of forest machine function on operator exposure to whole-body vibration in a cut-to-length timber harvester

The influence of machine function (tree felling and processing, and machine movement over the terrain) on operator exposure to whole-body vibration in a cut-to-length (CTL) timber harvester was evaluated. Vibrations were measured on the seat and the cabin chassis in three orthogonal (x, y, z) axes for the tree felling and processing, and during motion on a test track. It was found that the level of vibration transmitted to the operator during felling and processing was mainly affected by the tree size (diameter). For tree diameter at breast height (dbh) range of 0.25 – 0.35 m that was investigated, the vertical (z-axis) vibration component during processing increased by up to 300%, and increased by 50% during felling. However, the associated vibration levels were not sufficient to pose any serious health risks to the operator for an exposure limit of 8 h. Vibration at the operator seat and cabin chassis was predominant in the lateral (y-axis) and vertical (z-axis) respectively, during vehicle motion over the standard test track. Vibration peaks of approximately 0.20 and 0.17 ms^?2 occurred at 5 and 3.2 Hz respectively.     

基于UM的磁浮列车-轨道梁耦合振动仿真程序开发

基于大型通用多体动力学仿真分析平台Universal Mechanism(UM),开发用于磁浮列车 轨道梁耦合振动仿真的专用程序UM Maglev,其中：磁浮列车设置为多刚体模型,弹簧和阻尼器的刚度和阻尼视为线性或非线性力元;轨道梁设置为三维铁木辛柯梁模型,或从外部有限元软件导入模态分析结果;轨道线路包含平面和纵断面曲线、超高和轨面随机不平顺;悬浮和导向系统控制采用PID模型;多体动力学系统微分 代数方程求解采用Park刚性稳定法。该程序可用于考察磁浮列车的曲线通过性能、运行平稳性和乘坐舒适度,研究悬浮/导向气隙与磁浮控制系统参数优化,分析轨道梁在动态电磁力作用下的振动响应。     

Influence of forest machine function on operator exposure to whole-body vibration in a cut-to-length timber harvester

The influence of machine function (tree felling and processing, and machine movement over the terrain) on operator exposure to whole-body vibration in a cut-to-length (CTL) timber harvester was evaluated. Vibrations were measured on the seat and the cabin chassis in three orthogonal (x, y, z) axes for the tree felling and processing, and during motion on a test track. It was found that the level of vibration transmitted to the operator during felling and processing was mainly affected by the tree size (diameter). For tree diameter at breast height (dbh) range of 0.25-0.35 m that was investigated, the vertical (z-axis) vibration component during processing increased by up to 300%, and increased by 50% during felling. However, the associated vibration levels were not sufficient to pose any serious health risks to the operator for an exposure limit of 8 h. Vibration at the operator seat and cabin chassis was predominant in the lateral (y-axis) and vertical (z-axis) respectively, during vehicle motion over the standard test track. Vibration peaks of approximately 0.20 and 0.17 ms(-2) occurred at 5 and 3.2 Hz respectively.     

高速列车浮式地板振动响应有限元分析

针对采用试验方法开发高速列车浮式地板耗时耗力,且试验规模小,不能反映整车的振动效果的问题,基于有限元法进行高速列车振动响应分析.对三明治夹芯理论、蜂窝板理论和等效板理论进行比较,确定采用等效板理论数值模拟某浮式地板中的蜂窝板;利用橡胶材料的超弹性理论拟合橡胶材料参数;建立完整模型模拟实际工况下浮式地板的振动响应,得到浮式地板的隔振效果.结果表明此浮式地板的隔振效果约为90%,满足设计要求.     

Effect of tangent track buckle on vehicle derailment

In order to investigate the effect of a tangent track buckle on the dynamic derailment of a railway vehicle, a coupled vehicle/track dynamics model is developed, in which the vehicle is modeled as a 35 D.O.F. multibody system and the track is modeled as a 3-layer discrete elastic support model. Rails are assumed to be Timoshenko beams supported by discrete sleepers, and the effects of vertical and lateral motions and rolling of the rail on the wheel/rail creepages are taken into account. The sleepers are treated as Euler beams on elastic foundation for the vertical vibration, while as lumped masses in the lateral direction. A moving sleeper support model is developed to simulate the effect of the periodical discrete sleepers on the vehicle/track interaction. The vehicle and the track are coupled by wheel/rail contacts whereas the normal forces and the creep forces are calculated using the Hertzian contact theory and the nonlinear creep theory by Shen et al., respectively. The equations of motion of the coupled vehicle/track system are solved by means of an explicit integration method. A tangent track buckle is simulated with a cosine function, which describes the misalignment of the track with different lengths due to its buckling. In the analysis the effects of the buckle wavelength and amplitude and of the vehicle speed on the dynamic behavior of the coupled vehicle/track system are considered. The present paper analyzes in detail the conventional derailment coefficients which include the ratio of the wheel/rail lateral force to the vertical force, the wheel load reduction, and the new criteria indicating the wheel/rail contact point traces and the wheel rise with respect to the rail. These criteria are simultaneously used to evaluate the risk of derailment of the whole vehicle. The numerical results obtained indicate that the track misalignment caused by the buckle and the vehicle speed have a great influence on the whole vehicle running safety when the vehicle passes through the buckled tangent track.     

悬浮隧道基于弹性边界的力学模型与移动荷载响应分析

悬浮隧道是一种创新型的水中交通结构,这种悬浮于水中的结构在考虑复杂边界条件下的力学建模及交通荷载引起的结构响应值得深入研究.本文将跨度范围内由多段锚索支撑的悬浮隧道视为弹性支撑梁,同时将两端的复杂边界条件考虑为具有不同约束刚度的竖向和转动弹性支撑,流体荷载由Morison方程考虑,建立了悬浮隧道在任意荷载作用下的动力学模型及考虑自振特性的特征方程.研究了跨内支撑刚度与边界约束参数多种组合条件下的频率、模态分布特征,得到了相应的敏感区间.同时,以某型号高铁列车为背景并将其考虑为一列移动集中力,研究了悬浮隧道结构关键位置的荷载响应与弹性支撑刚度之间的关系,结果表明跨内支撑刚度、边界约束刚度均对竖向位移存在显著影响,整体上约束刚度越大,相应的位移越小.     

Natural vibration analysis of rail track as a system of elastically coupled beam structures on Winkler foundation

An analytical model for analyzing the vertical free vibration of a rail track is presented. The track structure is represented as a system of elastically coupled beam structures resting on a Winkler foundation. The rail and the tie beams are described by any combination of the two existing beam theories, the Bernoulli-Euler type, and the Timoshenko type, while the rail is assumed to be periodically supported at discrete points on cross-track tie beams. A generalized track element, which consists of a rail span (beam segment), two adjacent ties, and the coupling spring stiffnesses, is established to discretize the track system into identical units. A concept of an equivalent frequency-dependent spring coefficient for the rail support system is introduced to formulate the dynamic stiffness matrix of the track element. Solutions are provided for the natural frequencies of the track and the associated mode shapes of the rail and the ties under transversely (cross-track) symmetric vibration. The free vibration results are used to obtain the dynamic receptance response of a typical field track and to compare them with an existing model and field experimental data.