考虑桩土相互作用的船桥碰撞有限元数值模拟

发布时间：2018-12-13 05:08

【摘要】：对各种桥梁坍塌事故统计分析表明,船舶撞毁桥梁是导致桥梁坍塌的主要原因之一,分析桥梁船撞事故原由,研究船撞事故的发生规律对桥梁防撞设计有重要启示作用。同时,分析指出,桥墩是千米级斜拉桥防撞设计时的重点考虑对象。近些年来,得益于计算机技术的飞跃发展,有限元法为船桥碰撞问题提供了有效并可靠的分析途径,从而从众多的船桥碰撞研究方法中脱颖而出。为了寻找更为合理高效的有限元数值模拟方法,探究船桥碰撞过程的影响因素,本文以安徽省望东长江大桥为工程背景,精确建立船舶与桥梁实体模型后,运用LS-DYNA进行数值模拟分析。本文主要研究内容如下:(1)为了研究不同的桩土相互作用模型对船桥碰撞结果的影响,本文采用了“固定端”模型、p-y弹簧模型和有限域土体模型来模拟桩土间相互作用。并且,在这三种模型的基础上,借助LS-DYNA软件对船桥碰撞过程进行了数值模拟。通过对比不同桩土相互作用模型的数值模拟结果可以看出,动态有限元方法能够有效模拟船桥碰撞问题。(2)本文综合考虑了船舶与主塔的弹塑性反应,精确建立10000t带球鼻艏船舶与望东长江大桥望江侧主塔有限元模型,对船桥碰撞过程的影响因素进行数值模拟,包括水位线变化、不同船舶速度以及船舶撞击方向的改变,研究碰撞过程中能量的转化等计算结果。(3)综合考虑拉索力、桥梁结构及桩土相互作用后,本文建立了望东长江大桥整桥有限元模型,数值模拟非线性船桥碰撞过程,获得了船桥碰撞力、船艏与群桩基础变形等计算结果。探讨在船桥碰撞过程中,只建立桥梁主塔模型,对其余部位进行相应的简化与忽略,与建立整桥模型有限元数值模拟结果的差异,证实以单座主塔模型替代整桥建模的合理性。
[Abstract]:Statistical analysis of various bridge collapse accidents shows that ship collision is one of the main causes of bridge collapse. It is important for bridge collision design to analyze the causes of bridge collision accidents and to study the occurrence law of ship collision accidents. At the same time, it is pointed out that pier is the important object of collision prevention design of kilometer-scale cable-stayed bridge. In recent years, thanks to the rapid development of computer technology, finite element method (FEM) provides an effective and reliable way to analyze the collision problem of ship and bridge, and thus stands out from many research methods of ship-bridge collision. In order to find a more reasonable and efficient finite element numerical simulation method and explore the factors influencing the collision process of ship and bridge, this paper takes Wangdong Yangtze River Bridge in Anhui Province as the engineering background, and establishes the entity model of ship and bridge accurately. LS-DYNA is used to carry out numerical simulation and analysis. The main contents of this paper are as follows: (1) in order to study the influence of different pile-soil interaction models on the collision results of ship and bridge, the "fixed end" model is adopted in this paper. The p-y spring model and the finite field soil model are used to simulate the pile-soil interaction. On the basis of these three models, the collision process of ship and bridge is simulated with LS-DYNA software. By comparing the numerical simulation results of different pile-soil interaction models, it can be seen that the dynamic finite element method can effectively simulate the ship-bridge collision problem. (2) the elastoplastic response of the ship to the main tower is considered comprehensively in this paper. The finite element model of 10000t spherical nose bow ship and Wangjiang main tower of Wangdong Yangtze River Bridge is established accurately. The factors influencing the collision process of the ship and bridge are numerically simulated, including the variation of water level, the change of ship velocity and the direction of ship impact. The calculation results of energy conversion during collision are studied. (3) after considering the interaction of cable force, bridge structure and pile-soil, the finite element model of the whole bridge of Wangdong Yangtze River Bridge is established, and the nonlinear ship bridge collision process is numerically simulated. The calculation results of collision force of ship and bridge, deformation of ship bow and pile group foundation are obtained. In the course of ship-bridge collision, only the main tower model of the bridge is established, and the other parts are simplified and ignored accordingly. The difference between the finite element numerical simulation results of the whole bridge model and that of the whole bridge model is discussed, and the rationality of replacing the whole bridge model with the single-seat main tower model is proved.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U443.15;U447

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