Research On Finite Element Simulation Of Ship-ship Collision

At present,the marine accident investigation mainly adopts the methods of qualitative analysis of the ships' responsibility,which is based on the investigation of the ship's crew and the calculation of the data of the charts,the logbooks and the navigational instruments and equipment.As a part of the ship,especially small tonnage civilian vessels in inland river,fishing boats and others mostly are not equipped with GPS(Beidou satellite)navigation system,ECDIS,AIS,VDR and other equipment,so it is difficult to make a qualitative inference by the record data of navigational equipment for collision accidents of ships like these tapes.At the same time,in the accident investigation,the ship crew may tamper with the chart data and provide false statements in the maritime investigation in order to maintain the interests of themselves and the owner,which not only increasing the difficulty of maritime accident investigation,but also easily causing the disputes and grievances of the parties.Therefore,it is necessary to provide new technologies and methods to make maritime accident investigation and dispute settlement more objective and effective.The ship collision research is based on the finite element simulation technology,considering the influences of plastic deformation of the colliding ship's bow,the collided ship's speed and the surrounding fluid.The fluid-structure coupling finite element model is used to simulate the instantaneous process of ship collision.And combining with the inspection results for the parties involved in ship collision accident,the instantaneous collision angle and relative velocity are calculated in the collision moment,in addition,the ship structural damage deformation,the energy absorption and conversion of each component are analyzed during the collision.As a general method in ship structure damage and crashworthiness research,the finite element simulation technology is applied to the investigation of marine accident,which will provide a new method for marine accident investigation and maritime dispute settlement.The main research contents of this thesis are as follows:(1)Establishing the finite element model of ship collision.According to the caseanalysis,the finite element simulation model of the accident is established by MSC.Patran,and the related parameters are set up.(2)Determining the collision gesture of the ships in the collision moment.According to the record data of the shore station and ship navigation equipment,the corresponding simulation cases are designed firstly.Then through the simulation calculation and contrastive analysis of the actual inspection results after the accident,the instantaneous collision angle and relative velocity of the ships are determined when the collision occurring.(3)Analyzing the response of ship structures during the ship collision.During the ship collision,the structural damage and deformation,contact force and energy conversion of the ships are analyzed to restore the actual collision situation.(4)Responsibility confirmation of the ships.According to the simulation results,the ships' anti-collision action will be deduced,which provides the basis for responsibility confirmation between ships.(5)Making emergency maneuvering decisions when the ships encounter in imminent danger situation.Based on the comparative analysis of the structural damage deformation and energy absorption in different cases of ship collision,the collision situation is determined to minimize the ship's structural damage deformation,which provides emergency maneuvering suggestions for ships in case of imminent danger situation and inevitable collision,and then reduces ship collision damage.