Analysis Of Coupled Bending And Torsional Vibration Of Asymmetrical Ship Hull

In recent years,with the accelerating process of globalization and increasing marine disputes,various countries have put requirements for the manufacturing and the design of marine equipment.When studying the vibration of ships,the vibration is different from the vibration of an ordinary symmetrical ship.Some research has done on the vibration characteristics of asymmetric ship hulls in this article.First,the flexural-torsional coupled vibration equation of the asymmetric ship hull is deduced by the transfer matrix method,the asymmetric composite cross-section beam is designed,and the equation derived by the transfer matrix method is used to solve the free vibration frequency of the composite cross-section beam.Second,the finite element method was used to analyze the designed asymmetric composite section beam,the results obtained by the two methods were compared,and the vibration characteristics of the asymmetric composite section beam under the condition of simple support were analyzed.The analysis found that the asymmetric ship hull is in the vibration frequency when the two ends are simply supported is higher than the vibration frequency of the ship hull when the two ends are free.The dry and wet mode of the asymmetric section beam is also analyzed,and it is found that the frequency obtained by the dry mode analysis of the ship hull is higher than frequency obtained by wet mode analysis.Third,the finite element method is used to analyze the characteristics of the free vibration of an asymmetric hull at three different draughts.The research shows that the free vibration frequency of an asymmetric hull decreases with increasing draught.Fourth,the vibration response of an asymmetric hull at a certain draught under different current speeds and the dynamic response of the hull under different draughts at a certain water speed are explored.The research shows that when the draught is constant,the greater the water velocity around the hull,the greater the vibration displacement and vibration velocity of the hull.When the water velocity is constant,the vibration displacement and vibration speed of the hull increase with the increase of the hull draft.This shows that when the water velocity is constant,the dynamic response of the hull increases with the increase of the hull draft.