A Seismic Response Analysis of a Cylindrical Liquid Storage Tank Including the Effect of Sloshing : 2nd Report, Analysis Based on Energy Method

This paper presents a seismic response analysis method for a cylindrical liquid storage tank subjected to a horizontal earthquake, which is based on an energy method with the coupling effect between sloshing and bulging taken into consideration. The kinetic energy and the strain energy of an empty tank shell are estimated by the axisymmetric shell finite element method. On the other hand, the kinetic energy and the potential energy of the liquid in the tank are estimated analytically by superposition of two type of velocity potentials, that is, one obtained by assuming the tank wall as rigid and the other obtained by considering the liquid to be coupled with the tank shell neglecting the oscillation of liquid free surface. The numerical results obtained by this method are compared with those obtained by the method described in the former report, which treats Bernoulli's equation as the boundary condition of liquid free surface, and it is shown that there are little differences between them.