| Observations of the amount of sea ice in the polar regions show that the trend of sea ice loss has accelerated in the last decade,a trend attributed to global warming caused by rising greenhouse gas emissions.The Arctic shipping route is a new shipping route connecting Asia,Europe and North America formed by the melting of sea ice.The melting of sea ice improves the economic navigation ability of the Arctic shipping route,and its potential commercial value has attracted more and more attention.The fully opened Arctic shipping route will greatly shorten the shipping distance between China and major trading powers in Europe and North America,and stimulate greater trade potential.On the other hand,the Arctic region is rich in resources,and the Arctic shipping route provides a very convenient sea passage for the resources in these regions.Polar waters of level ice and ice environment under different ice will produce very big effect on resistance of ship by ice,and then affects the polar ice breaking capacity of the ship resistance and ice breaking efficiency,thus carry out the polar ships under the environment of level ice and ice ice resistance prediction and the parameter sensitivity study has important engineering significance,is the core of the polar ship design optimization of key problem.Based on polar icebreaker "Xuelong" as the research object,based on the principle of the Voronoi irregular geometrical shape and thickness of the random distribution of 3d parametric modeling compared with crushed ice,using nonlinear finite element software LS-DYNA fluid-structure interaction method of polar icebreaker under the environment of level ice and ice ice resistance hull suffered to carry out the numerical simulation research,Finally,the change rule of ice breaking resistance under different head configurations of icebreakers in ice breaking area is analyzed.The main research contents are as follows:(1)Study on the construction of three-dimensional discrete random distribution model of broken ice domain.The construction method of Voronoi diagram was studied,and the distribution probability of broken ice was determined by Voronoi principle.At the same time,a three-dimensional broken ice model with irregular geometric shape and random thickness distribution was built by referring to the actual distribution of broken ice area in the Arctic photographed by aerial photography,combined with Grasshopper,a parametric design tool.A stochastic ice breaking finite element model,which can be used for numerical simulation and is very close to the real ice breaking situation,is established,and the model is used in the subsequent numerical simulation of the ice breaking resistance of icebreakers.(2)Study on hull ice resistance prediction and parameter sensitivity in flat ice area.LS-DYNA fluid-structure interaction method was used to carry out numerical simulation of the ice load on the hull of the icebreaker in the level ice environment.The failure mode of the level ice during the ice breaking process of the icebreaker was analyzed.The influence law of the ship speed and the thickness of the flat ice on the ice-breaking resistance of the hull was studied.The numerical simulation results of ice-breaking resistance under various working conditions were compared with the results calculated by Lindqvist empirical formula.(3)Study on hull ice resistance prediction and parameter sensitivity in ice breaking area.Consider icebreaker sailing speed,and sea ice ice environment sensitivity parameters(crushed ice intensity,crushed ice thickness)of hull ice load,the influence of using LS-DYNA fluid-structure interaction method of crushed ice navigation icebreakers are crushed ice resistance to carry out the numerical simulation research,and analyzes the sensitivity parameter change on the influence law of crushed ice resistance.(4)Study on the effect of head parameters of icebreaker on ice breaking load in ice breaking area Based on the original head configuration of the icebreaker,the three head configuration parameters of the icebreaker were increased and decreased respectively,namely,the bow Angle,the camber Angle and the waterline approach Angle.Nine head configuration schemes of the icebreaker were obtained.Based on the LS-DYNA fluid-structure coupling method,the influence of the head configuration of the icebreaker sailing in the ice-breaking area on the ice-breaking ability was explored.In addition,the ice breaking resistance of icebreakers with different head configurations in the ice breaking environment is explored,and the influence law of different parameters on the ice breaking resistance of polar icebreakers is analyzed,which provides some reference for the design of icebreakers... |
