Research On Impact Resistance Design Of Hull Structure Under Collision Load Of Ice

As the global climate warms up, ice in Arctic regions is melting about nine percent a decade and resource exploitation in this area becomes more feasible. Arctic regions are rich in oil resources, such as natural gas, minerals and fishery resources. Therefore, resource exploitation in Arctic regions has drawn worldwide attention, especially to those coastal states. However, the ship-ice collision seems inevitable while ships sail in high latitude sea area. Once collision happens, it would probably damage the hull and cause cargo spill, environment pollution and even disastrous casualties. In order to promote large-scale and effective development of oil and gas resources in frozen waters worldwide, it is necessary to solve various problems caused by sea ice disaster.Based on the above reasons, research on impact resistance design of hull structure under collision load of ice has been carried out in this paper. First, this paper analyzes finite element simulation method and creates ice material parameters which apply to finite element simulation. Second, structure has been strengthened according to Ice Class Rules and transverse and longitudinal strengthening methods have been designed. By comparing with traditional unreinforced structure, it highlights the importance of ice structure strengthening as well as the superiority of transverse strengthening method. Then, based on strengthening specification, by discussing the plan of hull structure ice strengthening, regularity of the effect on general structure by increasing the strength of single component has been further analyzed. At last, two new impact resistance shoulder structure are designed, which compared to traditional shoulder structure, a better shoulder structure has been gained by comparative analysis of impact resistance. Main works are as follows:(1)Based on the elastic-plastic theory and non-linear finite element analysis software LS-DYNA, this paper analyzes the material model of ship-ice collision. Taking typical product tanker for example, it elaborates on finite element simulation technique of hull structure including modeling process of simplification of hull structure, mesh generation, contact definition, etc. The ice material parameters have been established. At last, by consulting the previous research, the paper approves the feasibility of ice material model and simulation method.(2)Taking a product tanker for example, using processing software PATRAN to build finite element model of ship and ice, collisions between ship without shoulder reinforcements, while with transverse and longitudinal reinforcements and ice have been simulated respectively. Different and similar responses of hull structure have been comparatively analyzed under different collision plans. It reveals the feasibility of the existing ice strengthening specification and the differences between transverse and longitudinal strengthening methods.(3)On the basis of ice strengthening according to Ice Class Rules, regularity of the effect on general structure by increasing the strength of single component has been further analyzed. Taking the oil tanker with transverse reinforcement as research object, on the premise that all other factors remain unchanged, by changing the thickness of external shell, the thickness of diaphragm plate and frame spacing, different structural dynamic responses of damage deformation, collision force and energy absorption are obtained. The influence rule of the above factors and the anti-ice load ability of each component can be concluded by comparing the different structural responses.(4)Applying sandwich plate to shoulder structure, two new kinds of anti-impact structures with shape of I and V have been designed. Based on non-linear finite element software LS-DYNA, this paper takes comparative analysis of dynamic responses of shoulder structure during collision with structure of traditional reinforcement, I-shaped sandwich plate and V-shaped one. It reveals the regularity and characteristics of damage deformation, impact force and energy absorption under different plans. Meanwhile, it also provides a better impact resistance structure.