Analysis Of Motions And Loads Of Ships In Combined Wind And Waves

In recent years,the rapid development of the international marine transportation also spawned the development of large-scale ships.The container ship as an example,the carrying capacity of new generation container ships can reach seven times more than the original.However,the development of large-scale ship also put forward higher requirements for the design and verification of ships.In real marine environment,the sailing ship is not only affected by the single wave load,the sea wind and the combination load of sea wind and wave also will cause greater impact on the hull response.Besides,due to the structure above the waterline of large-scale ship is enormous,it is more easier to be influenced by wind load.Therefore,it is necessary to predict the response of ships under the combined load of wind and wave.At present,the research on combination of wind and wave both here and abroad is mainly aimed at the development of offshore platforms,and the research content of sailing ships is less.Therefore,it is of great importance to establish a prediction system for ship motion and load response under the combined load of wind and wave,which is of great significance for the design of large-scale ship and the safety assessment of ships under strong wind and wave.In order to establish the prediction method of ship motion and load response under the combined load of wind and wave,the following work is completed:(1)By comparing and analyzing a variety of wind load calculation methods and selecting a method with high accuracy,compiled wind load calculation program by FORTRAN,realize by solving the steady and fluctuating wind time domain wind under different navigation conditions.(2)Calculate the wave force suffered by the hull in the waves by using the 3-D wave load calculation software COMPASS-WALCS-NE,the wind force and the wave force are combined to the hull motion equation and solve the motion,then the section load can be calculated with the d`Alembert principle,to realize the wind wave Combined action hull motion and load response calculation.(3)Using a 21000 TEU container ship as the computational model,due to the wind on the hull rolling greater impact,to analyze the law of rolling motion by combined wind and wave under different environmental parameters with full load condition,compared with the result of single wave load response to get the effect of wind force on the total response.And two kinds of container ships undercomplete loading conditions(Combo and OLG)were also selected to calculate the rolling motion of the hull,the difference between the two loading conditions under the same wind and wave conditions is analyzed.(4)The zero-speed hull tests are carried out to test the response of the load and motion under combined wind and wave loads,in order to further study the response of hull movement and load response,experiments were carried out to test the hull movement and load response under full load condition of container ship in both horizontal and oblique wave conditions and the response of rolling motion under the same conditions of wind and waves under two kinds of non-full load conditions.In this paper,the calculation method of ship motion and load response under the combined wind and waves is established,which can predict the sailing ship’s motion and load response under the condition of wind and waves.The effect of wind force on the hull response under different environmental parameters is discussed through the calculation of example.Finally,the experimental results and theoretical calculations were compared to verify the effectiveness of the theoretical algorithm.