Equivalent mechanical model for structural dynamic analysis of elevated tank like AP1000 PCCWST

Abstract

This study is motivated by a lack of information regarding the seismic analysis and design of AP1000 passive containment cooling system water storage tank (PCCWST). The major challenge faced in this specific type of fluid–structure interaction (FSI) problem is the estimation of the forces associated with the hydrodynamic pressure. In this paper, an equivalent mechanical model for the water tank of PCCWST was developed regarding the hydrodynamic pressure. Parameters of this newly-developed mechanical model, which was evaluated by finite element method (FEM), were given in chart form as functions of geometrical parameters including ratio of inner and outer tank radii, tank bottom’s inclination angle, and tank height. The values of impulsive mass were compared between the proposed model and the cylindrical tanks reported in the literature when their inclination angle approaches zero. The agreement shown by this comparison confirmed the validity of the proposed mechanical model. Shaking table experiments of a scaled PCCWST were also carried out to verify the feasibility of the proposed model. Finally, the transient response of PCCWST subjected to horizontal ground excitation was provided to illustrate the application of the proposed model. Therefore, the study shows that the equivalent mechanical model can provide an effective method for the design of PCCWST.