Safety Performance Of Ship Structure Based On Ice Load Measurement

With the continuous development of polar regions and the navigation of Arctic routes,the scientific research value and economic value of polar regions have become increasingly prominent.It has become an important part of polar strategy to explore and develop polar regions with polar research vessels.Therefore,the research on the safety of ship navigation in ice area is becoming more and more important.The impact of sea ice on the hull structure is an important factor affecting the navigation in ice area.However,the interaction process between sea ice and ship structure is very complex,including many scientific issues.Therefore,the real ship monitoring of ice load on the hull is not only an important means to ensure the safe navigation of ships in ice area,but also an important way to study the ice load distribution and change law.The main factor that affects the safe navigation of ship in ice area is the influence of sea ice on ship hull.Among the sea ice parameters,the ice thickness and density are the parameters that need to be heavily monitored when navigating in the ice area.The bad ice situation will affect the normal navigation route.In extreme cases,it will even lead to the icebreaker unable to continue to break the ice smoothly,resulting in ice jam.In serious cases,it is necessary to apply for the rescue of high-level icebreaker.Not only that,in the process of ice breaking,when the sea ice and the hull structure have impact extrusion interaction,the hull structure will vibrate and deform to a certain extent.The vibration of the structure will affect the normal operation of the ship’s equipment,the structural deformation will affect the overall strength of the ship,both of which will threaten the safety of the ship’s navigation.Therefore,ice load real ship monitoring not only needs to monitor the response of the hull structure to ensure the safety of the hull structure,but also needs to monitor the sea ice parameter information,which can not only ensure the safe navigation of the ship,but also can be used to assist the research of ice load distribution and change law.In this paper,based on the structure characteristics of the scientific research vessel XueLong,the sea ice image monitoring scheme and the ice load monitoring scheme of the hull structure are established.The real-time sea ice image monitoring is carried out for the bow,midship and stern of the ship,and the local ice load in the contact area between the bow and the sea ice is measured in real time.Based on the monitoring scheme,the parameters of sea ice thickness and sea ice density during the ninth Arctic expedition and the peak ice load data during the eighth Arctic expedition were obtained.Based on this,combined with the sea ice image video monitoring data,a Bayesian network is established to study the events of ships besetting in ice in the ice area,and the influence degree of different environmental factors on the events of ships besetting in ice is determined.Based on the Bayesian prediction model,the probability of ships besetting in ice under specific ice conditions is given.Through the finite element analysis of typical local stiffened plate structure of ships,the paper analyzes According to the advantages and disadvantages of different limit load criteria,combined with the reasonable limit load criteria,the ultimate bearing capacity of the hull structure under the ice load is determined.Based on the study of events of ships besetting in ice and the ultimate bearing capacity of the local structure of the ship,this paper provides a reference for the safety warning of the ship in ice area,which is helpful for the development of the digital monitoring and evaluation system of polar ships.