Investigation On Icebreaking Loads And The Motion Of Icebreaker

As the significant base of energy sources, the north and south poles possess own strategic importance because of their interest in economy, politics and military. Relative researches on icebreaker come to the strategic and economic of rank for development. Because of the particularity of the icebreaker's sailing area and operating environments, the interaction between ice and icebreaker is attracting a wide spread attention of researchers, but the research about ice load and motion response of the icebreaker is still in its infancy stage, there are many problems to be solved. The thesis mainly focuses on the theoretical analysis of continuous icebreaking processes and ship motions in six degrees of freedom. The main research contents are as follows:1?Some simplification and basic assumption are made for the icebreaking process, two basic coordinates and the transformational relation between them are established, and the differential equations of motion is introduced. Stress situation of icebreaker during icebreaking process is analyzed, and the semi-empirical formulas for calculating broken ice,propellers,rudders, surrounding fluid force are introduced. The Newmark's method is applied to solve the motion response in six degrees of freedom.2.The physical properties and mechanical behavior of sea ice are summarized, the interaction between ship and ice are analyzed. The ice force function containing two-time fracture is constructed on the base of experimental data and theoretical analysis.3.Based on the above theory, relevant procedure is written in MATLAB to calculate the transiting and turning processes, and the instantaneous ship motion is then achieved. The calculation program is validated by comparison with the data from related articles.4.The interaction between ship motion and icebreaking performance is analyzed by constraining any of the DOF(s).5.The effect on icebreaking performance of bow shape is discussed through altering different parameters of bow, including the stem angle and the camber angle.6.The thrust deduction in ice is derived, and the floes ice resistance in astern mode is modified, comparative study about icebreaking performance under ahead mode and astern mode were conducted.