考虑海域水位变化的船撞桥流固耦合分析

Fluid-Structure Coupling During Ship-Bridge Collision Process Considering Sea Level Variations

为研究水流对船撞桥过程的影响及水位对桥梁动力响应的影响,以金塘大桥非通航孔段连续梁桥为背景,采用ANSYS-LSDYNA软件建立流固耦合和附加质量2类船撞桥模型,分析流体对撞击过程中撞击力和能量转移的影响以及不同水位下桥梁各构件的动力响应,并通过缩尺模型试验验证流固耦合模型的正确性。结果表明:采用流固耦合法计算的撞击力幅值较附加质量法大15%左右;直接受撞区、桩基承台连接处、桥墩承台连接处是桥梁遭受船撞时的高危应力区;水位越高,撞击时桥梁上部构件的位移越大;低水位下,船舶直接与桩基发生碰撞,对桥梁下部结构的潜在破坏较为严重。

To investigate the influence of water flow on the ship-bridge collision process and the influence of water level on the dynamic response of a bridge,the non-navigable part of the Jintang Bridge that consists of continuous beam spans was taken as the study background,and the software ANSYS-LSDYNA was used to establish two types of ship-bridge collision models taking account of fluid-structure coupling and additional mass,respectively.The influence of fluid flow on the collision force and energy transfer in the collision process as well as the dynamic response of each bridge component at different water levels were analyzed,and the finite element model for fluid-structure coupling calculation was verified by the scale-down model test.The results show that the amplitude of collision force calculated by the fluid-structure coupling method is 15%bigger than that calculated by the additional mass method.The highly-risky stress areas will appear in the directly-attacked part,connection of piles and pile cap and the connection of pier and pile cap in the hitting process.Higher water level induces bigger displacement of the upper components of the bridge.When the water level is low,the direct collision of ship and pile foundation will cause more severe potential damage to the substructure of the bridge.