Study On Impact Resistance Of Pontoon Breakwater

The pontoon breakwater has been widely used in marine engineering,which has high ecological value and economic value.The breakwater is mainly used to protect the shoreline and cover the structures in the port.It can resist the erosion of waves and prevent the sedimentation caused by the water flow on the coast of the river bank,so that the water environment in the area is relatively stable;at the same time,it can prevent some small speedboats or large ships.The damage to the port structure caused by severe collisions and the damage of personnel and property will enable the ship to be safely parked in the port and maintain the normal operation of the hydraulic structures.It is found in the literature that is available now that scholars pay more attention to the wave-breaking performance of breakwaters,and the collision performance is less studied,so it is necessary to analyze the impact resistance of the pontoon breakwater in detail.The collision between the pontoon breakwater and the ship involves multi-disciplinary cross-cutting problems.In this paper,the finite element analysis software LS-DYNA is used to study the anti-impact performance of the pontoon breakwater.In this paper,the theory of collision response is analyzed and summarized.Based on this,several new types of vertical raft-type breakwater structures are proposed.The energy absorption,collision force and damage deformation of the breakwater structure under different collision parameters are studied.The impact resistance is evaluated comprehensively.Change the composition type of the pontoon breakwater structure,study the thickness of the outer panel,increase the SPS sandwich panel outer panel and the rubber buffer device to improve the impact resistance of the breakwater.The collision performance of the pontoon breakwater is evaluated by changing the collision parameters,which provides an idea for designing a new floating breakwater scheme.The research content of this paper is as follows:(1)This paper introduces the research status of ship collision at home and abroad and the theory of sandwich plate research.It briefly introduces the simulation method used in this paper,including material model setting,collision parameter selection,sandwich plate modeling method,etc.,and different pontoon breakwaters.The ship collision process is modeled to verify the feasibility of the numerical simulation method.(2)Based on the collision theory,a new type of longitudinal breakwater structure is proposed to study the collision resistance of different protective members.Since different collision parameters have a great influence on the simulation results,the other quantities are kept unchanged,and the deformation,deformation and energy of the collision area are studied when the single collision parameters change.Different collision ships will cause structural damage deformation mode changes in the collision area.Therefore,the collision simulation is carried out with the 26000 DWT ball nose oil tanker and the 1000 T oil tanker respectively to study the ship collision depth of different ship types.(3)The sandwich panel structure has a lot of advantages such as high rigidity and light weight.In this paper,the polyurethane sandwich panel is used to replace the steel plate structure,and the finite element analysis is carried out on the collision scenes at different positions and different collision speeds.The energy absorption of the outer panel accounts for a large proportion of the total energy absorption of the structure.Therefore,it is necessary to increase the thickness and rigidity of the outer panel to improve the impact resistance of the breakwater.(4)Rubber has a very significant shock absorption and energy absorption effect.In the paper,the rubber buffer device is covered on the outer surface of the floating box type breakwater,and the damage degree,collision force and energy change of the collision area structure are analyzed,and the rubber is added.The anti-collision performance of the breakwater after the buffer device provides theoretical basis and technical support for the follow-up work.