Analysis On The Slamming Loads And Responses Of Local Structures In The Bow And Stern Of Very Large Container Ship

With the continuous grow of economic ties between countries and the ever-tightening of environmental laws in recent years,very large container ships,for their higher carrying capacity,lower average shipping cost and less carbon dioxide emission,have made unprecedented strides in both application and technology.However,very large container ships usually come with large bow flares and they are more likely to experience slamming in high seas.In the meanwhile,very large container ships have a relatively flat bottom in the aft body,and slamming is prone to occur when there are large motions in waves.Slamming may cause severe damage to the local structures,and is a potential threat to navigation safety.Aiming at theoretical prediction of ship slamming load and investigation of local structure response,the following work has been carried in the thesis:1.Motion characteristics of very large container ships.The vertical motion of bow/stern relative to wave is studied as it is a major factor of slamming.A comparative analysis is conducted to study the bow/stern motion characteristics of a 10000 TEU and a 21000 TEU container ship.For the latter ship,additionally,the relative motion is also analyzed for the full-load and the ballast condition.2.Numerical simulation and validation.Numerical simulation of a 2D rigid body free-falling into water is performed and compared with experimental results in order to validate the numerical method.3.Investigation of the characteristics of bow/stern slamming load of very large container ships.The bow/stern section entering water at constant speed is simulated with the parameters equivalent to ship slamming occurrences at sea,and load characteristics at various locations is analyzed.The influences of presence of bulbous bow and propeller on the slamming load are investigated,and the analysis of sensitivity to speed has also been analyzed.4.Case study of a 21000 TEU container ship.The relative motion is calculated using the design wave method,and the time histories are obtained by means of numerical simulation.The time-varying load is applied to finite element models,and the dynamic responses of bow/stern structures are obtained.