Study On The Structure Of High Performance Anti-collision Fender Of Fier

The development of economy has promoted the construction of bridges and the development of water transportation,which caused a lot of ship collision accidents.A ship's collision with a pier will cause serious consequences,such as casualties,sinking of ships and destruction of piers.From the point of view of economy,safety and environmental protection,it is of great practical significance to take reasonable measures to prevent ship collision.Because of the economic,technical and other reasons,the research of collision avoidance devices can not be carried out by a large number of experiments,and the theory and finite element method provide a shortcut to solve the problem.Based on the concept of stiffness matching,the effect of the fender and the bow stiffness ratio on the performance of the fender is considered,and the influence of the stiffness ratio on the performance of the fender is analyzed by the finite element software.By adjusting the fender structure,the stiffness ratio of the high performance fender is obtained.At the same time,we put forward the idea of graded failure combined fender,and make full use of the characteristics of FRP and low carbon steel materials to analyze the crashworthiness of combined fender.The contents and results of this paper are as follows:(1)The collision theory and research method of the ship bridge are arranged and the working principle and use range of various types of anti-collision devices at home and abroad are analyzed,and the advantages and disadvantages of various kinds of anticollision devices are demonstrated by practical cases.The concept of composite fender with classified failure is put forward.(2)Starting from the mechanism of ship bridge collision,the collision process is discussed,and the concept of stiffness matching should be considered in fender design.Fender collision resistance is not determined solely by fender structure,but is influenced by stiffness ratio.The energy dissipation of the fender decreases with the increase of the stiffness ratio.(3)Study the influence of various factors on the fender performance.The results show that the anti-collision effect of the anti-collision fender is achieved by adjusting the stiffness ratio between the ship and the pier.Reasonable stiffness ratio can effectively reduce ship bow failure.The maximum ship collision fender force has a linear relationship with the speed and the square root of ship mass.With the increase of speed and ship quality,fender energy consumption is increasing,and the proportion of fender energy consumption to total energy of the system is decreasing.(4)Study the influence of fender structure on fender performance.Based on the calculation of the fender impacted by a 500 T bulk carrier,a case study is made on the influence of stiffness ratio on the fender performance.The results show that when the thickness of the steel plate is 5mm,the overall thickness is 0.5m and the polyurethane is not filled,the anti-collision fender has good protective performance.It can reduce the maximum collision force of the bulk carrier by 34.43%,and the energy consumption of the anti-collision protective fender accounts for 18.56% of the total energy.With the increase of stiffness ratio,the maximum collision force of steel fender and ship decreases first and then increases,and the maximum collision force is the lowest.With the increase of stiffness ratio,the energy consumption ratio of steel fender decreases.By calculating the results,the collision force and the formula for calculating the energy dissipation of the fender are obtained.The stiffness ratio of fender and bow to high performance steel fender is 12-40.(5)On the basis of the study of steel fender and FRP fender,the design of graded failure combined fender is carried out.The research results show that the FRP fender of the same specification has better performance than the steel fender in reducing the maximum ship collision force,and the energy dissipation performance is weaker than that of the steel fender.The combined fender based on the concept of graded failure can make full use of the advantages of the two fenders,effectively reduce the ship collision force and increase the energy consumption of fenders.