Abstract
Stochastic response of a thin elastic cylindrical tank, fixed on the sea bed in the ocean environment, subjected to wind-induced waves and horizontal earthquake excitation is investigated. The offshore tank contains liquid in its interior and on its exterior it is surrounded by another liquid of infinite extent, and therefore it becomes necessary to consider the dynamic interaction between the tank wall and the inside and outside liquid of the tank at the same time. At first, using the matrix progression method, the natural frequencies and mode shapes of a tank are obtained for several combinations of interior and exterior liquid depths. Then the results are used to determine the hydrodynamic pressures acting on interior and exterior surfaces of a tank subjected to waves and earthquakes and the response quantities of a tank, such as displacements, accelerations, resultant forces and moments, on the basis of a stationary random vibration theory. Numerical examples are solved and the dynamic behaviors of an offshore tank containing liquid are compared with those of an empty offshore tank.
