Name: Nicolás Castrillón Email: Send Gender: Male Hometown: Weston, FL Major: Mechanical Engineering School Name: University of Florida School Location: Gainesville, FL Graduation Year: 2008 When In China, Thing(s) Missed Most From USA: Ice cold 2% milk When In USA, Thing(s) Missed Most From China: White grape juice and a couple grad students Mentor: Professor Yue Qianjin Graduate Student: Guo Fengwei Research Abstract: Self excited vibrations of vertical structures in ice infested waters due to horizontal ice action can be very unpredictable since they occur when certain conditions coincide. These conditions include ice-structure relative velocity, ice make up, structure stiffness, etc. Self-excited vibrations, although rare, can be very detrimental to the structure as they can draw out for several minutes and could compromise its integrity, as well as cause worker discomfort, and thus reduce work efficiency. Determining a model that predicts the ice floe loading on the structure proves to be primary since it would allow engineers on site to control these self-excited vibrations. The model created was conceived from multiple field tests in on a jacket structure in the northern Bohai Sea by Yue et al. It was determined that a slanted sawtooth function would describe the ice load most accurately since it illustrates the slow loading process, the sudden failure of the ice when stress limit is reached, and the rapid unloading. This unloading phase takes up between 6-10% of the total period, which is the same for the structure’s natural frequency. The unloading phase does not fully reduce the load to zero, however. The magnitude of the load oscillates around an average point that is constant for the duration of the vibration, and measured in absolute units. The double amplitude of the oscillations typically covers 20-30% of the maximum. This model describes a self-excitation vibration phenomenon that is able to predict the horizontal loading history of the ice on a vertical structure.