【作者】 陈向东；

【导师】 金先龙；

【作者基本信息】 上海交通大学 ， 机械设计及理论， 2009， 博士

【摘要】 斜拉桥由于造型美观、受力合理、跨越能力强,成为近年来桥梁建设的主要桥型之一。随着社会经济的快速发展,一方面,斜拉桥的跨度越来越大,材料越来越轻;另一方面,车速不断提高、交通密度不断增加、载荷不断加重。车辆所引起的动荷载在斜拉桥整体响应中所占比重越来越大,导致斜拉桥结构产生疲劳,降低其强度和稳定性,影响行车安全和乘员舒适性。因此,对斜拉桥进行车-桥动态响应分析,掌握其动态响应特性是十分必要的。通过数值模拟方法计算斜拉桥的车-桥动态响应过程,可以确定斜拉桥的强度、刚度、行车安全性、乘员舒适性及其相关因素的影响,为斜拉桥结构设计提供参考依据。本文基于拟实建模技术及并行计算技术,对车-桥动态耦合系统及其耐撞性进行数值模拟研究。本文的主要研究内容包括:研究车-桥动态耦合系统数值模拟的基本理论。考虑到大跨度斜拉桥的几何非线性和车-桥之间的动力相互作用关系,从数值分析的理论角度出发,研究了几何非线性分析的基本理论以及动态接触的数值计算方法,为车-桥耦合系统动态响应的求解提供理论依据。在对几何非线性有限元方程求解时,采用更新拉格朗日格式中心差分算法;轮轨之间的相互作用通过基于罚函数的耦合方式加以实现。研究大跨度斜拉桥与轻轨车辆的全三维非线性精细有限元模型的建模方法。基于拟实建模技术,斜拉桥模型采用了板壳单元、实体单元、梁单元以及索单元等组合式单元模拟。轻轨车辆模型包含轮对、转向架和车体,它们之间采用弹簧和阻尼连接。将车轮与钢轨之间的相互作用看作是动态接触关系,通过建立轮轨三维动力接触模型将桥梁与车辆耦合在一起。轻轨车辆内建立两个乘员假人模型,分别为坐姿和站姿,用于分析乘员舒适性。研究适用于车-桥动态耦合系统的区域分解并行计算方法。斜拉桥的全三维非线性精细有限元模型单元数量巨大,普通的串行计算机难以满足这种大规模数值计算要求,因此需要采用并行计算技术。现有的节点数均衡的分区策略,没有考虑各子区域之间接触特性可能的不同,从而影响并行计算效率。根据斜拉桥车-桥动态耦合系统的特点,结合上海超级计算中心曙光4000A计算机的体系结构,在递归对分区域分解算法的基础上,提出基于接触均衡的区域分解法,相对于递归对分区域分解法,该方法有着更高的加速比和并行效率。研究车-桥耦合系统的动态响应。考虑到大跨度斜拉桥的几何非线性,首先确定大跨度斜拉桥的初始成桥状态,在斜拉桥成桥状态的基础上,数值模拟多种工况下车-桥耦合系统的动态响应。主要分析车速、双线运行和车辆紧急制动对斜拉桥刚度、强度的影响,以及对行车安全、乘员舒适性的影响,为斜拉桥设计提供细致、详尽的仿真计算结果。将斜拉桥精细有限元模型结果与已有的平面杆系有限元模型结果进行了对比,验证了模型的可靠性。研究车-桥动态耦合系统的耐撞性。船舶对斜拉桥的撞击作用通过建立船舶的三维有限元模型加以实现。将轻轨车辆、斜拉桥、船舶视为一个整体系统进行分析,基于此观点提出了面向车辆行驶过程的车-船-桥动态耦合系统的数值模拟方法。通过分析船舶撞击作用对行驶车辆的动态响应的影响,为桥梁设计更加合理的防撞设施提供了参考依据。更多还原

【Abstract】 The cable-stayed bridge has become one of the chief types for long span bridges due to its beautiful shape, reasonable bearing capacity, and long span ability. With the rapid development of science and technology, the bridges become more and more big and light. With faster and faster running, the increasing traffic density, and the increasing load, the dynamic interaction of the vehicle-bridge is receiving increasing attention. The numerical simulation method is used to calculate the dynamic response of the vehicle-bridge. Based on the virtual modeling and the parallel computing technologies, the dynamic couple system of the vehicle-bridge is studied. The dynamic couple system crashworthiness of the vehicle-bridge is also studied. The main contents include:The basic theory of the numerical simulation for the vehicle-bridge dynamic couple system is studied. Considering the geometric nonlinear of the long span cable-stayed bridge and the vehicle-bridge interaction, the geometric nonlinear theory and numerical method for the dynamic contact is studied. The Update Lagrange Formation is used to solve the geometric nonlinear equation. The penalty function method is used to deal with the wheel-rail interaction.The modeling technology of the refined finite element models of the long span cable-stayed bridge and light rail vehicle is studied. Based on the virtual modeling technology, the finite element model of the cable-stayed bridge is represented by the shell element, the solid element, the beam element, and the cable element. The vehicle model includes the wheel-set, the bogie, and the body, which are connect by the spring and damping. The three dimensional dynamic contact model of the wheel-rail is built. The two dummy models, standing and sitting, are set up to analyze the riding comfort.The parallel computing method of the vehicle-bridge dynamic couple system is studied in order to deal with so large model. Serial computer could not deal with this large-scale model. The parallel computing is necessary. Based on the character of the vehicle-bridge dynamic couple system and the structures of DAWNIING 4000A supercomputer located in Shanghai Supercomputer Center, the domain decomposition method based on the contact balance is proposed. Comparing with the recursive coordinated bisection method, the domain decomposition method based on the contact balance has higher speedup and parallel efficiency.The dynamic response of the vehicle-bridge couple system is analyzed. The initial state of long span cable-stayed bridge is determined firstly, which could provide the initial condition for the couple dynamic simulation of the vehicle-bridge. The influence of the velocity, two line, and brake on the stiffness, strength of the cable-stayed bridge and the vehicle safety and passenger comfort is analyzed, which can provide the detailed simulation results for the bridge design. The refined three-dimensional model and the plane beam model of the long span cable-stayed bridge are compared.The dynamic couple system crashworthiness of the vehicle-bridge is studied. The three dimensional numerical model of the ship is built. The light rail vehicle, the cable-stayed bridge, and the ship are analyzed as a whole system. The modeling method of the dynamic couple system of the vehicle-ship-bridge for vehicle running is put forward. The dynamic response of the cable-stayed bridge and the light rail vehicle under ship impact is analyzed, which can provide more reasonable reference for bridge crashworthiness design.更多还原