车辆振动模型作用下不平整沥青路面的动力响应

由于受到车辆荷载的影响,沥青路面出现了各种形式的破坏.为研究沥青路面的动力响应,明确其破坏机理,采用二自由度1/4车辆振动模型模拟车辆荷载,依据弹性层状理论体系,建立沥青路面三维有限元模型,通过车辆-路面相互作用系统分析动态车载作用下沥青路面不同深度的动力响应,并对车速的影响效果进行了研究.结果表明:(1)由应力随深度...     

车辆荷载作用下连续梁桥动力响应仿真分析

为研究桥梁在移动车辆荷载作用下的动力特性和承载能力,以某连续梁桥为计算实例,采用大型通用有限元软件ANSYS建立了质量-弹簧的车辆模型和桥梁结构的有限元模型,用时程分析法分析了车辆荷载作用下连续梁桥的动力响应特征,着重探讨了车辆刚度、车辆质量、行车速度等车辆荷载因素对连续梁桥动力响应的影响规律,并提出相应结论.     

简支梁桥在车辆荷载作用下空间振动特性分析

以福新桥为背景,分析了车道位置、桥面铺装层平整度、车速等因素对桥梁动力响应的影响,并对桥面动力响应频谱特征进行分析,得到一些结论,可为进一步研究公路车桥耦合振动提供参考。     

地震作用下钢桥面、系杆拱桥的动力响应

以位于美国匹兹堡、跨径为189m的伯明翰桥(单跨系杆拱桥)为对象，研究钢桥面、系杆拱桥在地震激励下的动力响应。考虑到桥面系的复杂构造，采用两种分析模型来模拟桥面系；运用标准模态方法，计算了两个分析模型的地震响应，并对计算结果进行了分析比较，其中采用1940年EI Centro波的3个正交地震波记录作为地震响应分析的输入。为了获得一个合理的响应模型且使计算花费最少，检查了模态的贡献，计算了桥面上指定点的位移和应力(以图形示出)。     

公路桥梁与车辆耦合振动现象模型与数值分析

随着桥梁建造技术的不断突破,大跨度和轻型已成为桥梁结构的主要发展方向,对公路桥梁在移动汽车载荷作用下的动力响应的研究越来越受到人们的关注.文章根据大量的研究资料,归纳叙述了公路桥梁与车辆耦合振动现象的重要性,并将该现象的模型系统划分为车辆和桥梁两个部分进行分析.     

我国公路桥梁疲劳车辆模型研究

基于府店路荷载调查资料,探讨了我国疲劳车辆模型的建立方法。将疲劳车辆加载于常用跨径简支梁桥上,分析比较了各疲劳车辆的疲劳损伤。通过定义疲劳损伤率,评估了各疲劳车辆的等效精度。在我国疲劳设计车辆尚未建立的情况下,建立疲劳车辆的方法对我国公路桥梁的疲劳设计具有一定的指导意义。     

重型车辆作用下钢栈桥振动响应对比分析

大件运输车辆通过没有交通设施的河道时需建立钢栈桥作为临时通行设施,钢栈桥在重车作用下的振动响应分析尤为重要。文中以一座钢栈桥为工程背景,建立105 t大件运输车辆,基于ANSYS/LS-DYNA程序建立显式车-桥耦合振动分析系统,研究105 t重车作用下钢栈桥的振动响应;将LS-DYNA计算结果与实测值对比,对钢栈桥有限元模型的刚度进行验证,使有限元模型与实桥更吻合。分析结果表明,保持车速一致,车辆质量增加一倍,钢栈桥振动规律基本一致,但跨中竖向振动位移变化显著;保持车辆质量一致,车速增加一倍,钢栈桥跨中最大竖向振动位移增大,且持续振动时间增长。     

曲线连续梁桥在移动车辆作用下的振动响应分析

分别建立了具有7个自由度的3D整车模型的振动方程和连续曲线梁桥的运动方程,将车辆和曲线梁桥分为相互联系的两个振动子系统——车辆和桥梁系统。利用有限元法及模态叠加综合技术,以车轮与桥面相互接触处保持不脱离为位移协调条件,推导出车桥耦合振动方程,并运用Newmark-β数值方法对耦合系统进行迭代求解。以一实际工程桥梁为背景,分析该曲线梁桥在单车荷载作用时,不同行车速度、不同路面等级的振动响应。结果表明:车速对曲线梁桥的竖向挠度的影响很大,但对横向振动的影响比较小;在同一车速情况下,路面的不平度对曲线桥梁的冲击影响显著,路况越差,冲击越大;曲率半径越大,桥梁的横向振动响应越小,而竖向振动响应却越大。     

桥梁检测可靠性的研究

美国联邦公路局（FHWA）的无损评价鉴定中心（NEVC）为了确定公路桥梁观测的可靠性开展了一项综合研究，其总目标是全面测评常规和深入检测的可靠性及精确度，研究人和环境因素对检测可靠性的影响。     

大跨桥梁在不同荷载作用下的动力响应监测

桥梁结构的动力特性是结构动力计算和抗震分析的基础,也是桥梁健康状况监测的一个重要指标。该文根据加速度响应时程曲线分析了某大跨斜拉桥在重车、船撞、大风、爆破地震等各种荷载作用下的振动响应,得出大跨桥梁在不同荷载作用下的动力响应特性。     

Application of the structural articulation method to dynamic impact loading of railway bridges – a case study

This article demonstrates a practical application of the structural articulation method. An existing prototype railway bridge was selected to compare our new method with the industry codes of practice. The response history and dynamic increment of the bridge were investigated through a variety of methods: lump sum mass analysis (LSMA) and suspension system analysis (SSA) for a single-axle force, and SSA for multi-axle forces. We considered both a local irregularity and a global sinusoidal irregularity. The dynamic impact load induced by either form of track irregularity increases approximately linearly with the vehicle speed up to a certain point, then tends to decrease gradually. This behaviour reveals that the dynamic impact load induced by track irregularities is dominated by the resonance of the bridge. If a bridge must support multiple axles, or if an especially accurate dynamic impact factor is required for safety reasons, then multi-axle SSA is recommended because this approach is the most accurate and likely to produce a weaker response than single-axle analysis. The random irregularity is generated by the stochastic track irregularity process. It is found that the dynamic impact load induced by the random irregularity is negligible, compared with the deterministic irregularity.     

路桥过渡段车路动力学分析方法研究

为探寻路桥过渡段桥台与引道之间容许差异沉降的理论确定方法，车辆采用两自由度体系模型，路桥过渡段采用不设搭板的台阶模型，行进方向取下桥向，认为车辆通过路桥过渡段作自由振动，给出了车辆振动方程和初始条件，分别用振型叠加法和拉普拉斯变换法进行了车路动力学分析，求出了人的竖向加速度和路面对车辆的作用力。2种方法计算结果非常吻合，表明当车辆模型和路桥过渡段模型较复杂时，路桥过渡段车路动力学分析可以采用拉普拉斯变换法，其中拉氏数值逆变换采用Crump法，计算程序的编制采用MATLAB语言。     

Train–track–bridge dynamic interaction: a state-of-the-art review

ABSTRACT

Train–track–bridge dynamic interaction is a fundamental concern in the field of railway engineering, which plays an extremely important role in the optimal design of railway bridges, especially in high-speed railways and heavy-haul railways. This paper systematically presents a state-of-the-art review of train–track–bridge dynamic interaction. The evolution process of train–bridge dynamic interaction model is described briefly, from the simplest moving constant force model to the sophisticated train–track–bridge dynamic interaction model (TTBDIM). The modelling methodology of the key elements in the TTBDIM is systematically reviewed, including the train, the track, the bridge, the wheel–rail contact, the track–bridge interaction, the system excitation and the solution algorithm. The significance of detailed track modelling in the whole system is highlighted. The experimental research and filed test focusing on modelling validation, safety assessment and long-term performance investigation of the train–track–bridge system are briefly presented. The practical applications of train–track–bridge dynamic interaction theory are comprehensively discussed in terms of the system dynamic performance evaluation, the system safety assessment and train-induced environmental vibration and noise prediction. The guidance is provided on further improvement of the train–track–bridge dynamic interaction model and the challenging research topics in the future.     

The dynamic response of rail support

This research reviews principles behind the dynamic response of rail supports, and introduces a method of analysis to find the maximum response in a realistic setting. Assuming a time-dependent, moving mass with massive wheels is essential, because the ratio of the moving mass to the rail mass is significant. However, the dynamic response of the track is not affected by dynamic properties of the train other than its unsprung mass, because the natural frequencies of the train suspension and track are significantly different. A numerical method is developed to model the dynamic response based on these principles, and applied to the Korean urban transit. The dynamic response includes multiple peaks with a large amplitude range, creating noise while the wheel passes the support. The dynamic impact factor (DIF) for the rail support depends mainly on the stiffness and damping of the rail support. The DIF for the rail moment is below the code value, whether this value is based on numerical analysis or on-site measurements. However, our numerical analysis results in a DIF for support settlement that is greater than the code value, if the damping is less than 3%.     

车辆动力荷载分析

采用模态迭加法对复杂结构在多支座随机位移激励下的振动进行随机振动分析，以载重货车为计算对象，求得在不同车速和工况下车辆荷载的均方根值和超载概率，讨论动荷载的概率特征。     

基于ANSYS的高速公路路基动力响应特性模拟分析

以京化（北京-阳原县化稍营）高速公路二期路基工程为研究对象,借助非线性有限元数值分析软件AN-SYS进行了数值仿真模拟,研究分析车辆动荷载作用下路基的动力特性。结果表明：车辆动荷载作用下,路基动应力随深度的增加而呈衰减趋势;车辆动荷载对路基竖向动应力值σy影响较大,而水平向动应力值σx影响相对较小;车速差异对路基动应力值影响显著;动应力值沿水平方向衰减较快,其传递距离存在一定的范围。     

混凝土公路斜桥的动反应研究

随着车辆质量、速度的逐渐增大和桥梁结构的逐渐轻柔化，车桥相互作用问题越来越受到关注。分别应用拉格朗日方程和模态叠加法建立三维非线性车辆模型和桥梁的振动方程，车轮与桥梁在接触点满足接触力和位移协调条件，利用迭代技术求解二者的相互作用问题。并以公路斜桥为分析对象，研究了不同斜交角、不同车辆行驶状态下以及不同行车速度情况下，横向不同梁的动挠度和动态增量。结果显示，斜交角、车辆行驶状态以及车速均是影响桥梁动反应的重要因素；当车辆行驶速度在30、40km／h左右时，梁的动态增量达到最大；而且随着斜交角的增大，离车辆行驶位置越远的梁的动态增量也越大。     

A structural articulation method for assessing railway bridges subject to dynamic impact loading from track irregularities

This paper discusses the importance of track irregularities in railway bridge design, and presents a new technique for calculating the dynamic impact load induced by such irregularities: the structural articulation method. The properties of the combined bridge-suspension system are coupled through global mass, stiffness, and damping matrices. Under the proposed method, the true suspension system over a particular point on the bridge girder at time t is divided into equivalent suspension systems attributed to adjacent finite-element nodes of the bridge. The time-dependent effects of a moving mass are thereby included in the equation of motion.     

先简支后连续梁桥车辆冲击系数影响因素研究

针对先简支后连续梁桥的结构特点,采用板单元及实体单元模拟连续梁桥,使用9自由度的三维整车模型模拟汽车荷载,考虑桥面不平顺,建立了该类桥梁的车桥耦合振动响应分析模型.结合模态综合技术和Newmark-β数值积分方法进行迭代求解.以某座典型的4跨先简支后连续梁桥为算例,分析了该桥在单车荷载作用下,行车速度、路面等级、车辆自...     

铁路桥梁模态参数测试方法的探讨

述评目前铁路桥梁模态参数实测中的技术现状,对其所涉及的规范条文、关键技术及方法的可靠性、适用性展开讨论。强调信号处理所必须遵循的求实、客观原则及动测问题的复杂性与专业性。对今后的改进提出建议。