Analysis Of Ship Navigation Safety In Bohai Sea Ice Age

From December to April of the next year,there will be light or heavy ice floes in the Bohai Sea.The length of ice age,distribution range,thickness,surface accumulation and other factors in different navigation sections affect whether ships can safely pass through the Bohai Sea.Because ships often collide with ice floes in the Bohai Sea in winter and the ship hull is damaged or grounded due to deviation from the artificial channel,it is uncertain whether ships can safely pass the Bohai Sea.Most ships stay in the port,which seriously affects the normal operation of conventional ships.Once they rush out to sea,the loss of crew life and property caused by accidents is incalculable.At present,there is a big gap in China’s research on safe navigation in winter in the Bohai Sea area,and there is no complete finite element analysis of ships’ navigation in winter in the Bohai Sea area.Therefore,this thesis has carried out the research on ship navigation safety in the Bohai Sea ice age.(1)In this thesis,a 30000 t bulk carrier is taken as the research object.Aiming at the above problems,a research scheme for safe navigation in the ice floe area of the Bohai Sea is proposed.Based on the detailed investigation of the Bohai Sea,the statistics of the sea state and ice condition data in the Bohai Sea in winter are made,the factors affecting the safe navigation of ships in the Bohai Sea in winter are determined,and the influence and harm of the wind,wave,current,foam ice and sea ice on the safe navigation of ships in the Bohai Sea in winter are summarized.(2)Secondly,the calculation formulas of wind,wave,current,wave spray ice,gravity,hydrostatic pressure and other loads are determined according to the requirements of the specification.(3)The additional mass finite element analysis method adopted in this thesis is determined,and the research process of finite element modeling in this thesis is introduced.According to the actual navigation situation of the ship in the Bohai Sea in winter,the finite element model is es Tab.lished and six working conditions are set,including the relative speed between the ship and the ice floe,the angle of action between the ship and the ice floe,the size of the ice floe,the thickness of the ice floe,the carrying capacity of the ship,and the direct navigation and steering of the ship.(4)The calculation and analysis method is proposed,and the six working conditions set in this thesis are calculated,and the results are summarized and analyzed.The calculation results show that the damage degree of the ship hull increases by 16% and the displacement of the offset channel increases by 75% with the increase of the relative speed by one knot.The damage degree of the hull increases by 9% when the floating ice increases by 1 m.For every5 cm of ice floe thickness,the damage degree of the hull increases by 20%.The damage degree of the hull will increase by 71% for every 10000 t increase in load capacity.The displacement of the offset channel increases by 90% for every 30° increase in the interaction angle between the ship and the ice floe.When encountering floating ice with a radius of 5m,a thickness of 25 cm,a 30000 ton ship with a load of more than 20000 tons sails in the Bohai Sea,when the speed exceeds 7.78 knots,the ship will be damaged.When the speed is 5.83 knots,even if the 30000 ton ship is fully loaded,the ship will not be damaged.The 30000 ton ship is sailing with full load at a relative speed of 5.83 knots.When the angle between the ship and ice is 150°,the deviation of the ship hull is 27 m every hour when the ship and ice floe act.Finally,according to the analysis results,this thesis summarizes the matters that should be paid attention to when the ship conducts relevant operations in the Bohai Bay in winter and puts forward the plans and suggestions for safe navigation.The research results of this thesis can provide a reference for safe navigation in the Bohai Bay in winter.