Large Scale Model Experimental Study On Wave Load Of Ultra-large Container Ships

Affected by the gradual recovery of the shipping industry,ultra-large container ships are favored by ship owners of various countries because of their low construction cost,low single-box transportation cost and large single-carrying capacity.Due to the structural characteristics of the hull,the super-large container ship is likely to cause nonlinear hydrodynamic slamming.For nonlinear problems and impact loads,it is often difficult to rely solely on numerical calculation methods,and the calculation results may be difficult to meet the structural design requirements of real ships.Model tests should be used as a necessary analysis tool.In the traditional pool test,because the conditional limit model can not be subjected to real and high sea wave,this paper adopts the large-scale model physical simulation test technology which can better simulate the slamming response of the ship under high sea conditions.The container ship is subjected to a model test to study its motion and load characteristics,thereby conducting a safety assessment of the ship.The main research contents of this paper are as follows:1)Measure the marine environment in the Huludao sea area,and compare the wave spectrum of the sea area with the ITTC single-spectrum spectrum by spectral analysis and non-dimension,and select the appropriate sea area for the experiment.It is found that the sea wave spectrum and the ocean spectrum of the test sea area are roughly similar in the characteristic parameters such as the center frequency and the energy distribution,which meet the requirements of the test environment.2)Design the test ship model,design the hull shell,the center keel beam,the position of the measuring point,etc.on the basis of geometric similarity,similar fluid dynamics,similar motion,select the matching propulsion system and control system,and finally determine the ship model assembly Program.3)Complete the large-scale ship model test under the seven-level sea conditions of the actual ship,and analyze and process the test data based on the spectrum analysis method.Select typical conditions for short-term analysis and very short-term analysis.Comparing the large-scale ship model test data with the numerical simulation results,the results show that the error is about 10%,which further proves the superiority and advancement of the large-scale ship model test technology under actual sea conditions.4)Conduct a safety assessment of the ultra-large container ship using a standard calibration method.By comparing the extreme values of the motion and load data on several days,and comparing with the corresponding allowable values in the specification,it is found that from the perspective of hull motion and total longitudinal strength,at 7,8,and 9 levels.Under sea conditions,the ultra-large container ship is safe to sail.