Numerical Calculation Of Ice Load On Ship With DEM Simulation And Analysis Of Ship Ice-Induced Vibration Measurement

As we enter the 21st century, the global economy is developing rapidly and human activity area gradually expands from land to ocean. Economic globalization lead to the development of the shipping industry. More and more people pay close attention to the arctic route channel which is an important channel of maritime transport in the future. In order to guarantee the safety and stability of the hull when vessel sailing in the ice, it is necessary to research the ice load on the hull and the ice-induced structural vibration.Sea ice is a kind of material having complex physical and mechanical properties, which will cause ice load influenced by ice type, ice thickness, strength, etc. In addition, the hull structure form, speed and other factors will also have influence on ice load. This paper first introduces the research of ice load on the ship hull and other structures by the domestic and foreign scholars, and summarizes the research methods and progress in ice load. It can find that the discrete element method can satisfactory simulate the fracture phenomenon after the crushing between ice and hull. Therefore, this paper mainly adopts the discrete element method to research the ice load of the ship hull, and the discrete element method has been briefly introduced in this paper.According to the physical and mechanical properties of sea ice, this paper has established sea ice model and structure model with discrete element method and illustrated the contact model, bond model, fault model, hydrodynamic model between the sea ice units and the contact model between triangular structure unit and sea ice unit.This paper has simulated the process of "Snow Dragon" sailing in the flat ice and the interaction between sea ice and the propeller by using the discrete element model. This paper has counted the distribution of local ice pressure on the hull and ice line load at waterline and analyzed the influence of ice thickness and ship velocity to the total ice force and the local ice force. In addition, the numerical simulation of the milling and impact between sea ice and propeller has also been carried out. The changes of local ice pressure during the milling and impact of the sea ice and the propeller have been counted. The influence of milling thickness and advance ratio on the ice force under the action of milling and the influence of the impact velocity and the size of ice cubes on the ice force under the action of impact have been discussed.The ice-induced vibration is an important factor to reflect the hull ice load in the process of ship navigation in ice. Analysis of the local hull vibration data by measured in 32nd Antarctic scientific expedition is to research the hull local ice induced vibration response. The influence of the ice thickness and the ship velocity to the vibration acceleration has been discussed.