Study On Mechanism In Ship-bridge Collision And Equipment For Anti-collision

Ship-bridge collisions are often catastrophic events, big probability of such accidents have aroused broad attention of the ship area and the bridge area. In recent years, study on the bridge resisting ship colliding has been carried out broadly, and there are two important being probed: the first is to analyze and understand behaviors of their structures and energy absorption mechanism in collision, and the second is to develop effective measures to improve the practicability of anti-colliding installations.Ship collision is a complicated non-linear dynamic response process under extreme large load in a very short time. The structures in collision region often surpass elastic state quickly and turn into plastic state companying with large deformation, flexure and fracture. Because of the complicacy and the uncertain factors in collision process, it is nearly impossible to make theoretic analysis by building up an accurate mathematic model. Therefore, numerical simulation by finite element analyses will play a more and more important role in the analysis of collision problems between ship and bridge or equipment for ant-collision.This paper is mainly about two questions: colliding mechanics mechanism and energy absorbing characteristic. On the basis of studying and discussing the key technology of compute calculate and emulate, employing ANSYS/LS-DYNA program, which is the universal nonlinear dynamic analysis software, a head-on collision between ship and pier protective device designed for Guangzhou River Bridge is simulated and presented, the simulation of time history course of full-scale mini-collision between ship and pier protective device was calculated. By analyzing the energy dissipation law and comparing the effect on energy absorbing by structure style, present some measures to optimize the structures. The major work in this thesis is listed as follows:1. Basing on the mechanics mechanism of colliding between ship and bridge, discussing the key problems in collision numerical simulation, such as the fundamental controlling equations, the FEM dispersion equations, the materialstrain rate sensitivity and the friction force effect etc.2. Studying the relational methods that deal with the modeling of the ship and crashworthy installation; comparing the accuracy of different simplify ways, advancing some new points on how to deal with the fluid force effect on the ship when colliding.3. By means of the FEM simulation soft ware, calculating the impact process of a ship colliding with the pier guard installation, drawing some conclusions about the energy absorbing characteristic of the structure components and energy dissipation law.4. Contrasting the effect of changing the structure style on the absorbing capacity of kinetic energy, and presenting some suggestions on how to make the structures easy to absorb energy and better to resist colliding.