The Dynamic Response Analysis Of Open Wharf Of Ship Collision

There is not breakwater or natural barrier cover of the open wharf. At present,building deep-water ports is the main trend. In recent years, with the marine technology and the major channel conditions are improved, the capacity of ship is increased. The trend of large ship is becoming more and more obvious. Because the large size of the ship can withstand strong wind and waves and the economic benefit is higher in the transport process. In the process of unloading dock, the requirements of stability conditions are relatively lower. But professional handling equipments are needed because of the major loading dock, which creats conditions to the construction of open wharf. it is very important on the research of dynamic response of open wharf because the impact force of the ship under wave action is often the main horizontal load of the wharf. In this paper, a 100 thousand ton tanker and Jiangsu port open wharf as the research object, a numerical simulation method is adopted and the response of ANSYS/LSDYNA finite element software of open wharf power structure in a 100 thousand ton oil under impact is analyzed.The basic theory of structural fluid structure coupling analysis is firstly introduced in this paper, including the description of fluid motion, the basic equations of fluid motion, the classification of fluid solid coupling problem and the establishment of fluid structure coupling equation. Then the theory of structural modal analysis is introduced. At last, the basic theory of the numerical solution of the structural collision is introduced, including the simplified motion equation of the ship motion, the theoretical method of the collision between the ship and the terminal, and the theory of the additional mass method.In this paper, a finite element model of open wharf structure and water is established using ANSYS software. Modal analysis of open type wharf based on the fluid solid coupling condition is carried out. The natural frequency of a total of three ranges is stable in the ten order modal distribution of open wharf structure model. The numerical value of the natural frequency of wharf model structure increases with the increase of modal order number. At the same time, the dynamic characteristics of open type wharf is also analyzed and discussed. The natural frequency of the open wharf under the condition of low water level, high water level and no water are compared, The natural frequency of wharf structure is smaller than that under water condition, and the numerical value is smaller than that under the condition of lowwater level under the condition of high water level. Because in the modal analysis, the effect of water on the pier model structure natural characteristics in water functions in form of added mass and damping in the structure, resulting in reducing the natural frequency of the model structure of wharf, which provides a theoretical reference on the analysis of vibration characteristics, vibration fault diagnosis and optimal design.On this basis, 10 million tons of oil ship is simulated to hit open wharf structure with different speeds. In the ship and open type wharf structure collision process, the kinetic energy of ship will be transformed into the ship’s own internal energy(deformation) and the residual kinetic energy, open type wharf structure of internal energy(deformation) and kinetic energy, the hourglass energy and slip energy, and the energy of the system is conserved..According to a series of data obtained, the transformation tendency of the system energy, displacement time history and the maximum impact force during the impact process is studied. At last, the distribution of the equivalent stress at different times is analyzed according to the vonmises stress atlas of open wharf. In ship and wharf collision process, high stress will be produced ship and the pier concrete structure contact surface area, pile supported pier and superstructure connection region and middle platform and on both sides of the berthing pier connected region.And corresponding improvement and reinforcement measures are also put forward.