Sloshing analysis of rectangular fluid-structure systems with a submerged structure for seismic loading

Abstract

Sloshing analysis methods for a rectangular fluid-structure system with a submerged structure for seismic loading are presented, and sloshing responses under the ground motion are investigated through numerical examples. The effects of the size and location of the submerged structure on the sloshing frequencies and mode shapes are also investigated. The fluid container and the submerged structure are assumed to be rigid, and the fluid is assumed to be homogeneous and ideal. Using the linear water wave theory, time history and response spectrum analysis methods are developed. The results of the example analyses are in good agreement with those by different methods. The sloshing frequencies and mode shapes are found to be significantly influenced by the size and location of the submerged structure. In general, sloshing frequencies reduce, as the submerged structure becomes tall and wide. The variations of the sloshing frequencies and mode shapes due to the submerged structure are found to be more sensitive in broad tank than in tall tank. Sloshing responses depend mainly upon the characteristics of the ground motion and the geometrical properties of the fluid-structure system. Generally, the sloshing amplitude, hydrodynamic pressure, and base shear and moment decrease as the excitation frequency increases, and the submerged structure becomes tall. The variation of the sloshing responses by the width and location of the submerged structure is found to be small. However, the variation of sloshing frequency due to the change of the size and location of the submerged structure may increase sloshing responses significantly. For the ground motion dominated by low frequency, the sloshing responses in the broad tank increase significantly and the contribution of the higher sloshing modes increases greatly. Hence, sufficient higher modes are to be taken into account in the analysis. It is found that the sloshing responses are more affected by the maximum velocity of th...