Mechanical Model And Dynamic Response Study On Collision Problem Between Bridge Pier And Vessel

In recent years with the rapid development of the amphibious transportation in our country, the number and scale of vessels and bridges are growing. Pier as a substructure for passing the upper structure load to the foundation are collided by the vessel more and more frequently. People’s lives and property are suffered great damage by these vessel-bridge collisions. Therefore vessel-bridge collision problem has become a hot focus on academia and engineering, particularly in terms of impact force calculation and capacity upgrading design of the pier anticollision. In this paper, based on the collision theory and finite element method, combined with the related theory of the structural dynamics and vibration, structure by mechanics model of ship collision problem is established. This paper mainly studies two aspects:the dynamic response and impact force estimation of the impact process.Aimming at different characteristics of bridge structure, this paper establishes the impact mechanical model of rigid/flexible pier and put forward the homologous impact force simplified calculation formula. At the same time based on nonlinear finite element software ANSYS/LS-DYNA, finite element model of ship collision and piers was established and briefly describes the finite element simulation technology applications on ship collision piers problem. This paper enriches the related theory of the ship bridge collision problem related theory and method of the impact force estimation. These results of the paper can provide certain guidance and reference on pier anticollision design and reinforcement. The main contents of this paper are as the follows:Firstly, aimming at rigid bridge pier under ship collision problems:we conceive mechanics model of impact system and establish the impact of system dynamic equation, then the theoretical analytic solutions of dynamic response and impact force are obtained. And then discusses the effect of three parameters(the impact velocity, the quality and ship contact spring stiffness) on the impact force result. Lastly, we get the impact force simplified calculation formula on this collision system mechanics models with numerical fitting software, then contrast and analysis the numerical results with the relevant specification formula calculation results.Secondly, aimming at the flexible piers under ship collision problems:we conceive mechanics model of impact system and establish the impact of system dynamic equation, then the theoretical analytic solutions of dynamic response and impact force are obtained. The correctness and effectiveness and of this algorithm based on the mechanical model is verified by the sample application and finite element software simulation. And then discusses the effect of four parameters(the impact velocity, the quality, ship contact spring stiffness and the axial force) on the impact force result. Lastly, we get the impact force simplified calculation formula on these collision system mechanics models with numerical fitting software, then contrast and analysis the results with the relevant specification formula calculation results.Thirdly, numerical analysis of ship-bridge collision model based on the nonlinear finite element software ANSYS/LS-DYNA:we establish the ship impact bridge finite element model and get the results of the dynamic response and impact force results on the collision process between the ship and the bridge piers.Finally, based on the contrast and analysis on three respect results:the finite element model calculation results, the numerical fitting of simplified formula calculation results and the relevant specification formula calculation results, the analysis method and the impact force estimation on ship-bridge collision problem are estimated and summarized. Furthermore, the paper put forward my own views and understanding on the bridge pier anticollision design and its’research and development in the future.