Research On Optimal Design Of Ice Belt Structure In Bow Of Polar Icebreaker

The development of polar heavy icebreakers plays an important role in the development of Arctic oil and gas and the opening of Arctic waterways.Icebreakers can be used for rescue in ice waters,guide ships to navigate,provide material transportation,and assist scientific investigations and other important tasks.When icebreakers perform missions in polar waters,sea ice problems will inevitably occur.The i MPact load will cause hull damage,damage to ship equipment,or loss of function.The weak links shown by icebreakers in the i MPact environment come from the ship and ice.Ice zone where loads interact.There is little research on the ice zone design of polar ships in my country,and there is still a certain gap between the world’s advanced level.To solve the current problems,it is necessary to speed up the construction and research of my country’s polar ship regulations,and actively overcome the technical problems in the ice zone of polar ships.Based on the above reasons,this article mainly carried out the optimization research on the ice belt structure of the side and bow of the icebreaker,which plays an important role in reducing the construction cost of the icebreaker and increasing the economic benefits.It can realize the goal of the design and construction of the polar ship and the autonomy of key supporting equipment as soon as possible.The main work of this thesis is as follows:(1)Research on structural optimization and collision theory of polar icebreaker.Introduce the algorithms related to ship structure optimization,which can be divided into classical optimization,intelligent search optimization,and optimization based on proxy models;introduce the mathematical models used in ship structure optimization,and introduce the objective function,design variables and constraints of the mathematical model respectively;system It expounds the improved feasibility direction method and theoretically analyzes the structure optimization approximate concept,optimization algorithm and optimization process involved;(2)Research on the mechanical properties of steel used in polar heavy icebreakers at different temperatures.The mechanical properties of the polar icebreaker steel were tested at different temperatures,and the stress-strain curves of the material at different temperatures were obtained.The elastic modulus,yield strength and tensile strength of the material at different temperatures were obtained through curve calculation.The foundation has been laid for the optimization of the ice belt structure on the side and bow of the icebreaker;(3)Research on optimization of bow and side ice belt structure of polar heavy icebreaker.The design ice load of the side and bow ice zone area was calculated with reference to the IACS rules.Based on the results of the material tensile test at room temperature,the structural response results under different loading methods were obtained,and the structural optimization loading method was determined;The dimensions of the longitudinal girders,ribs,and outer plates are optimized parameters.For the bow,the dimensions of the longitudinal girders,ribs,middle and inner keels and outer plates are optimized parameters.The ice belt structure of the icebreaker bow was optimized.On the premise that the strength meets the requirements,the optimization plan with the lightest structural quality as the optimization goal;(4)Co MParative study of ship-ice collision before and after optimization of polar heavy icebreaker.Based on the actual situation of the ship-ice collision,the ship-ice collision scheme in this thesis was designed;the polar heavy icebreaker collision icebreaker was simulated,and the dynamic response results of the icebreaker before and after structural optimization were studied and co MPared.The angle proves the reliability of the optimization results.