刚架拱桥车辆振动可视化仿真研究

【作者】 唐意；

【导师】 陈燊；

【作者基本信息】 福州大学 ， 结构工程， 2003， 硕士

【摘要】 本文运用可视化仿真的方法研究车辆荷载作用下刚架拱桥的动态响应。首先建立车辆、路面和桥梁三者的分析模型，将刚架拱桥按拱片(包括拱上结构和桥面系)离散成由112个二维梁单元组成的有限元模型，将一辆典型载重汽车理想化为具有四自由度的弹簧质量块系统，将路面的不平整视为符合一定路面功率谱密度函数的静态随机过程，利用伪随机数生成方法生成与国家标准对应的优、良和一般三种不同的路面平整度系列。 本文提出新的计算桥梁车激振动反应的方法，车—桥系统被分成两个相互作用的子系统，这两个子系统通过接触点的协调条件耦合在一起，从而应用Aiken动态加速法对桥梁运动方程、车辆运动方程和车—桥耦合方程进行高效迭代求解。基于上述方法，本文深入分析若干物理参数包括车速、桥梁阻尼、路面平整度和桥梁约束条件等对桥梁冲击系数的影响。 鉴于近期学术界对桥梁车激共振动机理存在不同认识，本文进一步研究在不同车速、不同车距和不同方向的多车荷载作用下津淮刚架拱桥的动力响应。计算结果表明，公路桥梁也存在多个瞬态响应相互叠加的问题，但由于受车辆行驶速度和阻尼因素的影响，津淮刚架拱桥没有出现明显的共振峰值。 基于计算可视化原理和方法的讨论，本文提出了简单易行的实现动态响应可视化的方案。并以OpenGL为图形工具，建立津淮刚架拱桥的二维模型，对计算得到的大量数据进行合理处理和可视化表达，完成了车辆作用下津淮刚架拱桥的动力响应时程分析的计算机仿真和动画显示，有助于对车桥复杂振动过程的理解和认识。更多还原

【Abstract】 The purpose of this paper is to use a visualization approach to simulate the dynamic response of a framed arch bridge under moving vehicle loads. Firstly, Models are developed for vehicles, road surface (roughness) and the bridge. Jinhuai Bridge is modeled as a planar bar system by 112 beam elements. The vehicle is simulated by a 2-D sprung mass system with four degrees of freedom according to a typical truck. The surface irregularity of the bridge pavement is considered as a stationary random process characterized by a power spectral density function (PSDF) of the surface irregularity. The irregular profile of the bridge pavement is generated from the PSDF using Monte Carlo simulation technique for very good, good, and average roads according to GB7031-86 specifications.A new numerical procedure for analyzing the coupled vibration of a framed arch bridge with a single moving vehicle is presented to solve the equations of motion of a bridge with many degrees of freedom. The procedure consists in dividing the bridge-vehicle systems, which are solved separately, into 2 subsystems at the interface of the bridge and vehicle. The compatibility at the interface is obtained by an iterative procedure with Aitken acceleration. Based on the above numerical procedure, parameter study, including the vehicle velocity, damping of the bridge, road surface roughness, and constrained freedom of the bridge, is conducted to investigate the influence of some important bridge and vehicle parameters on the impact ratio of the bridge.For recently there are some different opinions about the mechanism of bridge resonant vibration excited by moving vehicles, further study is done in this paper to analyze the dynamic response of Jinhuai Bridge under multiple vehicles with different velocity, moving direction and distance between two adjacent vehicles. From the results, we can see that Jinhuai Bridge has no noticeable vertical deflection peak. It is mainly because of the restrictions of some parameters such as velocity of the vehicle on highway and damping of the bridge, which can limit the peak values.Based on the principle and method of computing visualization, an easily implementing procedure for dynamic graphic description is proposed. A two-dimensional model of Jinhuai Bridge has been established in the paper with OpenGL as graphic tool, and a high-resolution animated cartoon simulation of Jinhuai Bridge under the moving vehicles has been accomplished.更多还原