Research On The Hydrodynamic Analysis Of Anti-collision Device For Approach Span Bridge

With the rapid development of economic construction,China has become the main battlefield of the construction of the world’s cross sea and river project,and has built a number of large bridges.These large bridges are more convenient for land transportation,but it hindered the ship’s route.The ship and bridge collision occurred continuously,serious bridge crash will cause enormous economic losses and huge social impact.How to avoid or mitigate the disastrous consequences of the collision between the ship and the bridge is an international issue,and it has attracted more and more attention from the academic,engineering and bridge management departments.Therefore,in order to avoid and reduce the occurrence of serious accidents,it is very important to study the technology of bridge collision avoidance.An adaptive arresting net crashworthy device has been developed for protecting non-navigable channel piers against ship collisions,which consists of mooring floating boats,mooring cable and mooring anchors,adaptive floating buckets,arresting net,triggering wire rope and constant resistant force cables.When a ship impacts the adaptive arresting net crashworthy device,one head of the adaptive floating buckets will rise due to the floating force,then the arresting net can capture the ship.Enormous kinetic energy of ship is consumed by a series of resistant force cables failure.The ship collision tests at full scale and hydrodynamic analysis of the adaptive arresting net crashworthy device had been conducted.The motion response of the crashworthy device impacted by ship was observed and discussed.The experimental results show that the arresting net is adaptive and the ship can be prevented successfully.Using the hydrodynamic analysis program AQWA which is based on the theories of potentialflow and diffraction/radiation to establish the numerical simulation model of the adaptive arresting net crashworthy device.In the process of modeling,the small floating block is used to replace the contact between the rope and the ship,which solves the problem that the contact between the ship and the rope is difficult to set.Then use the AQWA Cable Winch and Cable Failure function to set the initial velocity for ship.According to the above steps,a set of hydrodynamic calculation technology for adaptive ship arresting device is established which is simple,fast and complete.Comparing the numerical results with the real ship impact test,results showed that the numerical simulation results are in reasonable agreement with the experimental results,which can provide important reference for design and optimization the anti-collision device structure.On this basis,analysis the influence of different conditions and different forms of mooring facilities arresting sea-keeping performance,when the arresting system is not under the impact of the ship.Analysis of key parameters such as arresting device of floating body and mooring cable form trigger root number,spacing,adaptive buoy mooring chain length,angle of ship,then found that the mooring form of the floating body and the length of the mooring chain have obvious influence on the blocking performance.