Research On The Extreme Value Prediction Of Icebreaking Load Of Icebreaker Based On Arctic Ice Area

With the development of global economy,the demand for natural resources is increasing gradually.Because the polar region has plentiful of natural resources,it will be strategic commanding point of the game between countries in the future.Excellent hull performance can ensure the full development of polar resources.For ships serving in ice areas,ice load prediction is a crucial issue for hull structural design and safety assessment.In fact,the interaction between ship and sea ice is very complicated.The ice loads and sea ice conditions acting on the hull are highly random.However,the classic icebreaking load calculation methods are deterministic analysis,which cannot reflect the randomness of the ice load.In order to reasonably assess the icebreaking load of the icebreaker,this paper considers the randomness of the sea ice thickness and icebreaking load.Based on the measured dat a of the sea ice thickness in the Arctic,a virtual ice plate with thickness varying with space is established.A sufficient number of ice load data are obtained based on the numerical simulation model.Moreover,the extreme value prediction method is used to predict the extreme value of icebreaking load of icebreaker.The details are as follows:First of all,the sea ice thickness data in the Arctic is analyzed statistically.The distribution rule of sea ice thickness is determined by nonparametric estimat ion method.Then,the probability density function is determined,and the goodness of fit is tested by K-S test method.Based on the probability density function,a sufficient number of sea ice thickness data are generated by the selective sampling method in Monte Carlo simulation,and a virtual ice plate data model is established.Secondly,based on the data model of the virtual ice plate,the numerical simulation of navigation process of icebreaker in the virtual ice plate is carried out.Then,the numerical results are compared and verified by using the classical theoretical calculation methods,and the influence of different mesh accuracy on the numerical simulation results is investigated.Moreover,based on the numerical simulation results,the variation law of ice load in the whole and local area of the icebreaker is studied.Finally,the ice load time-history curves are obtained based on the numerical simulation.The peak amplitude method and asymptotic method are used to predict the ice load extreme value of the icebreaker in the straight and rotary state.And the influence factors and characteristics of the two methods are compared and analyzed.