The Application Of Visualization Techniques For Offshore Structures Sea Ice Accumulation Process

Developing the study concerned with sea ice breakup, overlapping and pile up is important in analyzing the reliability of sea ice design parameters on offshore structure, sea ice numerical simulation and prediction. Due to the dynamic characteristic of sea ice in Bohai, the floating ice fracture, overlapping and pile up is happened in front of structures under the action of wind and current. According to the characteristic of sea ice in Bohai, the mechanism of ice breakup, overlapping and pile up on inclined breakwater and semi-circle breakwater is analyzed, and the process of sea ice pile up is simulated visually.Assuming the sea ice to be viscous-elastic material and satisfied the Newtonian dynamic theory, the process of sea ice pile up on inclined structure and semi-circle structure is simulated using the discrete element method, which is based on Hopkins multitudinous polygonal blocks numerical simulation. The ice sheet is separated into many blocks with random length and the reasonable initial condition and boundary condition are given.Because the process of sea ice climbing and pile up needs a great many geometry and material parameters, and the output results of numerical simulation program contain ice block position , it is fussy and not intuitionistic to clean up the result. To optimize the program , the visualization technology is applied in this thesis. With the object-oriented property of VC++ and advantage of OpenGL in graphics, the data file is created visually and the interaction of ice sheet with inclined breakwater and semi-circle breakwater is manifested dynamically and visually using the output result of numerical simulation program.With the ice move simulation system, the interaction of ice sheet with structure is analyzed in three aspects: (1) ice sheet rupture mode ,pile up characteristic and the ice force before different gradient inclined breakwater and different water level semi-circle breakwater;(2) ice sheet rupture mode with different initial speed, pile up characteristic and the ice force before different gradient inclined breakwater and different water level semi-circle breakwater;(3) ice sheet rupture mode, pile up characteristic and the ice force before different gradient inclined breakwater and different water level semi-circle breakwater with different search frequency.By analyzing ice sheet rupture mode, pile up characteristic and the ice force, we obtain the disciplinarian of the ice pile up and understand its mechanism. It can be adopted as a reference of sea ice design parameters on offshore structure.