NONLINEAR SLOSHING ANALYSIS OF CYLINDRICAL LIQUID STORAGE TANK WITH SINGLE-DECK TYPE FLOATING ROOF

Abstract

This paper proposes a finite element method for nonlinear sloshing analysis of the liquid storage tanks with the single-deck type floating roof. The elastic finite elements with geometrical non-linearity are applied on modeling the floating roof, and the liquid elements are formulated based on the potential theory and the variational principle. The interaction problem of the elastic body and the fluid is formulated based on the variational principle, therefore the equilibrium equations are simply derived. The 100,000kl tank struck by the 2003 Tokachi-oki earthquake is modeled for the numerical example, and the seismic response analysis is performed. As this result, it is found that the high-order mode vibration, of which deformation is the 1st radial mode and the 3rd circumferential mode, might occur as the second mode vibration grows on the floating roof, and large stress such that the pontoon is collapsed might appear in the floating roof.