Research On Springing Behavior Of Container Ship Hull Girder

Large container ships have an irreplaceable position in today’s international transportation.However,today,as the ship’s main scale continues to increase,hydro-elastic problems are becoming more and more apparent.Due to the special large-open ship type of container ships and the use of a large number of high-strength steels,the natural frequency and the structural rigidity of large container ships are both reduced.Under the continuous excitation of the waves,a longer-lasting hull resonance phenomenon,springing,is generated.Even in low conditions,due to the decrease in the natural frequency of the hull,it will resonate with the wave frequency encountered in the low-frequency region,causing severe springing of the ship.When a large container ship is sailing,if it is subjected to springing for a long time,the resulting high-frequency vibration stress will cause fatigue damage to the hull structure.Therefore,compared with the ultimate strength of ship structure,it is also an important research topic to study the springing characteristics of large container ship hull girder and to provide guidance for reducing ship structural damage.In this paper,the three-dimensional hydroelastic theory is used to theoretically calculate the springing.At the same time,the pool model test is carried out,and the effects of heading angle,speed and loading state on the p\sprnnging are studied.The main research contents are as follows:(1)The application research of three-dimensional hydroelastic theory in the calculation of springing response of hull is carried out.Taking a 21000 TEU large container ship as an example,the hull beam mode and the springing response characteristics under regular wave action are studied by hydroelastic theory.(2)The 21000 TEU large container ship wave load segmentation model pool test was carried out to simulate the motion response of the actual ship under various working conditions.The rationality of the calculation results of the hydroelastic theory method was verified by analyzing the ship model test data.The mechanism and law of wave-induced vibration.(3)A comparative study of different numerical calculation methods was carried out.At the same time,the hydrodynamic method and the three-dimensional frequency domain Rankine source method were used to calculate the motion response and springing of the 21000 TEU large container ship.The two calculation results and the model test results were obtained.Compare and analyze the advantages and disadvantages of different methods in numerical prediction of large container ship motion response.Through the above research,the paper systematically analyzes the mechanism and law of the springing of the hull structure from the theoretical and model tests.Through the comparative analysis of the two calculation methods,the hydroelastic method is used to calculate the springing response of the large container ship.The superiority is verified by model test results.The research results reveal the springing response characteristics of large container ships,and have a guiding role in how to reduce large-scale ships from structural damage caused by springing.