桥墩遭受船舶撞击的数值模拟法及其动态响应的研究

桥梁防撞结构的设计需要研究桥梁遭受船舶撞击时的动态响应并获得准确的碰撞力.运用LS-DYNA软件建立了1座分离式桥墩模型和1艘3 000 t级的散货船模型来模拟船桥碰撞的过程.为了考虑流体在碰撞过程中的作用,计算时分别以不考虑流体影响、附加质量和流构耦合3种计算模型来分析、比较流体对船桥碰撞响应的影响,并得出以下结论:不同的计算模型的系统能量变化和船舶碰撞力基本一致,流体的存在对碰撞力的影响较小;桥墩的水平位移响应要滞后承台约0.2s,附加质量模型的桥墩和承台水平位移比其余2种模型要略大;附加质量模型的计算结果与流构耦合模型的计算结果基本一致,但附加质量模型具有更高的计算效率,其计算用时仅为流构耦合模型用时的2/5.

Numerical Simulation Method and Dynamic Response of Ship-bridge Collision

Designing bridge＇s anti-collision structure needs the dynamic response towards collision and exact colli- sion force. In this paper, a discrete pier model and a 3000 DWT cargo ship model are established by LS-DYNA to simu- late ship-bridge collision process. For considering water influence in the impact process, no-water model, additional mass model, and fluid-structure coupling model are used to compare and analyze water＇s impact on the dynamic response of the pier and ship. The results show that the collision force of different models is very close to each other, and water makes little difference on the collision force~ the pier＇s horizontal displacement happens 0.2s behind the pile cap＇s, and the hori- zontal displacements of the pier and the pile cap in the additional mass calculation model are slightly larger than those of the other two models; the results of the additional mass model and the structure-fluid coupling model are very similar, while the additional mass model is much more efficient in calculating, and its computation time is only 2/5 of the structure-fluid coupling model＇s.