액체 탱크의 진동특성에 관한 연구

Abstract

The structures used in the fields of fisheries, marine, machinery and aerospace are becoming larger, faster and more diversified. These structures have various shapes of tanks. Fuel, ballast, and fresh water tanks, which are present in vessels and marine structures including fishing vessels, are mostly in contact with fluids. In the fuel tank and fresh water tank, the level of the liquid in the tank is changed due to the operation of the ship, and the ballast tank is ballasted to maintain the equilibrium of the ship according to the load condition of the cargo. It is reported that such a tank may cause a resonance phenomenon due to an excitation force caused by operation of an engine, a propeller, a wave, and a ship auxiliary device, and cracks and breakage are caused by fatigue damage. Therefore, it is important to accurately estimate the vibration characteristics of these tanks in contact with the fluid.BR In this paper, the fluid - structure interaction problem is formulated by using the finite element method for the structure of rectangular tank and the boundary element method for fluid. The vibration characteristics of the elastic plate composing the tank through the boundary condition and the thickness variation were investigated in a tank structure having a height relatively higher than the length and width. According to the results of the study, the natural frequencies are affected by the boundary condition and shape of the tank.