高速行驶的汽车撞击桥墩过程中桥墩的受力行为研究

发布时间：2019-06-12 19:29

【摘要】：随着我国交通事业的蓬勃发展，跨线桥增多，在缓解交通压力的同时也带来了诸多不确定因素，一旦遭受车辆撞击，将会产生严重的后果。因此，对汽车撞击桥墩的研究相当必要，本文基于显示动力非线性分析软件LS-DYNA对汽车撞击桥墩进行了仿真分析，主要工作如下：一．回顾了国内外关于汽车与桥墩撞击的研究概况，介绍了LS-DYNA程序的功能特点以及实际操作过程中的控制问题。二．本文第三章建立了车与桥墩碰撞的简化有限元模型，比较分析了几种截面形式的桥墩在遭受撞击后的响应，初步提出了汽车与桥墩碰撞时应考虑汽车与桥墩接触形式的观点。另外，比较分析了常用的几种混凝土本构模型和桥墩配筋率对撞击响应的影响。三．本文第四章建立了汽车与整桥碰撞的有限元模型，研究表明：车重、车速增加会导致撞击力、墩顶位移的增加，在能量足够大时，汽车接触刚度发生变化（变大），因而增长率增大，通过对比分析，得出了本文分析模型下汽车接触刚度发生变化的临界能量值、临界车重和临界速度；在撞击总能量相同时，速度大的能量组成方式，峰值出现早，质量大的组成方式，撞击作用时域长，等效静力最大，当质量和速度都相对较大时，撞击力峰值最大；墩顶位移对撞击质量最为敏感；混凝土强度等级提高会减小墩顶位移，但增大了撞击力峰值；简化模型研究表明：上部结构对撞击力影响很小，墩顶固结、作用均布力于墩顶或在墩顶建立质量块的简化建模方式误差都很小，特别是在防撞设计时，墩顶固结计算值大，，偏安全，建议采用。
[Abstract]:With the vigorous development of transportation in our country, the number of cross-line bridges has increased, which not only alleviates the traffic pressure, but also brings many uncertain factors. Once you are hit by a vehicle, it will have serious consequences. Therefore, it is necessary to study the automobile impact pier. In this paper, the vehicle impact pier is simulated and analyzed based on the display dynamic nonlinear analysis software LS-DYNA. The main work is as follows: first, the research situation of automobile and pier impact at home and abroad is reviewed, and the functional characteristics of LS-DYNA program and the control problems in the actual operation process are introduced. 2. In the third chapter of this paper, a simplified finite element model of vehicle-pier collision is established, the responses of several cross-section forms of piers after impact are compared and analyzed, and the viewpoint that the contact form between automobile and pier should be considered when the vehicle collides with the pier is put forward. In addition, the effects of several common concrete constitutive models and pier reinforcement ratio on impact response are compared and analyzed. 3. In the fourth chapter of this paper, the finite element model of vehicle collision with the whole bridge is established. The research shows that the increase of vehicle weight and speed will lead to the impact force and the displacement of pier top. when the energy is large enough, the contact stiffness of automobile changes (becomes larger), so the growth rate increases. Through comparative analysis, the critical energy value, critical vehicle weight and critical speed of vehicle contact stiffness change under the analysis model are obtained. When the total energy of impact is the same, the energy composition mode of high velocity appears early, the mass composition mode appears early, the time domain of impact action is long, the equivalent static force is the largest, when the mass and velocity are relatively large, the peak value of impact force is the largest, the displacement of pier top is the most sensitive to the impact mass, the increase of concrete strength grade will reduce the displacement of pier top, but increase the peak value of impact force. The simplified model research shows that the superstructure has little influence on the impact force, the consolidation of the pier top, the error of the simplified modeling method of uniform force on the top of the pier or the establishment of mass block at the top of the pier are very small, especially in the anti-collision design, the calculation value of the consolidation of the top of the pier is large and safe, so it is suggested that it should be adopted.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U443.26;U441

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