Numerical Simulation Study On Collision Accidents Between Fishing Vessels And Bridge Piers

In recent years,with the rapid development of coastal shipping industry,coastal fisheries have also developed at a high speed.Therefore,there are more and more coastal fishing vessels,which leads to management inconvenience and the occurrence of collision accidents.In the event of a collision,the collision between the fishing boat and the pier accounted for a large proportion.In order to prevent losses caused by accidents,the study of fishing boat and bridge pier collision accidents has become an important research topic.Therefore,it is very necessary and meaningful to study the collision between fishing boats and piers.In this paper,by simulating the collision process between 42 m trawlers and different shapes of piers,the paper uses Patran modeling and Dytran calculation to study the damage of fishing vessels with different initial speeds,different eccentric distances and different angle collisions.Firstly,the fishing boats are attacked at different initial speeds and collided with different shapes of piers.It is found that the greater the speed,the more serious the collision damage of the fishing boat,and the shape of the piers that are collided is different and the damage is different.And when the speed is less than three knots,the collision structure damage of the bow is less obvious.Through the calculation of finite element numerical simulation,the curves including the collision force,velocity and energy(kinetic energy,variable performance,hourglass energy)are changed with time,and the histogram of the maximum displacement with speed is obtained.Finally,the displacement and stress are generated.Strain cloud map.Through data processing,the collision force,velocity,energy and other changes of the collision are related to the speed and related to the shape of the pier.From the histogram of the displacement and the analysis of the displacement and stress-strain cloud map,the fishing boat collides with the pier,and the fishing vessel bow is the main energy absorption carrier.The deformation of the fishing boat bow absorbs most of the kinetic energy,and a small amount of initial kinetic energy is taken by the pier.The deformation energy and the hourglass energy and friction energy during the collision process are absorbed.Secondly,the collision damage of the fishing boat with different eccentric distances and different angles striking the pier is studied.Firstly,the fishing boat is selected at the same speed,and the cylindrical pier with a radius of 2m is selected to collide with the eccentricity of 0.5m,1m,1.5m and 2m.It is found that the distance of the offset is larger at the same speed.The more serious the collision damage of the bow is,the more the ship’sraft structure goes to the sides,the worse the structural strength of the bow is,and the more easily the deformation occurs during the collision.Secondly,it is analyzed that the fishing boat is colliding with the elliptical pier at the same speed,and the collision damage deformation of 15°,30°,45°,60° and 75° is studied.It is concluded that at the same speed,as the angle increases,the collision damage course first decreases and then increases.It indicates that the collision damage of the bow is related to the angle of collision,but it is not completely proportional.It also shows that the collision between the fishing boat and the pier is also related to the position of the ship’s collision.Through a large number of numerical simulations,the collision results of fishing boats in different motion postures can be obtained,and expert data can be established to provide a reference for the treatment of collision accidents.