Analysis On Slamming Loads And Structure Strength Of Ships With Large Flare

Slamming phenomenon is particularly prominent for large flare ship.At present,the classical theory of water entry of 2D wedge sections or the empirical formula are often used for the slamming calculation of ships.It is poor targeted for a particular ship type with the limited scope.It is necessary to seek a method to predict the slamming load and assess the strength of the bow flare structure which can also reflect the characteristics of ships and suit for engineering application.The following research work was carried out in this paper:(1)By comparing the results of classical 2D wedge theory with numerical simulation method,the applicability of the numerical simulation which used to predict the 2D wedge slamming pressure coefficient was verified.The experiment investigation of water entry was designed to predict the slamming pressure coefficient of ships.The reasonableness of the numerical simulation aimed to predicting the coefficient was demonstrated by comparing the results of experiment with numerical simulation.(2)The method used to calculate the 3D correction factor was deduced through the classical theory which considered the spatial characteristic of ship hull.The 3D wedge models were used to simulate the process of entering the water and the rationality of numerical simulation was verified.The 3D effect was obtained by analyzing the test result and compared with the classical theory.(3)The method for calculating dynamic and synchronous correction factor was gotten under the consideration of characteristics of slamming pressure.The relative motions between ship and waves were analyzing and the short-term extreme value was taken to calculate the design velocity of slamming.The method for designing slamming pressure was derived after considering the effects of coefficients of slamming pressure,design velocity of slamming and correction factors.(4)The effects on structure strength assessment of factors were studied such as scope of slamming,loads condition and boundary condition.A ship’s structure strength was assessed under the slamming loads by the method presented in the paper.The assessment results were compared with results gotten from rules check and the advantage of the former was verifiedA method has been provided to predict the slamming loads and to assess the strength of the bow flare structure in the paper.The method can provide design references for the structure in slamming area of ships with large flare.