Earthquake induced sloshing and hydrodynamic pressures in rigid liquid storage tanks analyzed by coupled acoustic-structural and Euler-Lagrange methods

Abstract

Three-dimensional (3-D) ground-supported cylindrical and rectangular rigid liquid storage tanks filled with water and subjected to seismic base excitation are investigated using finite element method (FEM). The analyses of the tanks are carried out using coupled acoustic-structural (CAS) and coupled Eulerian-Lagrangian (CEL) approaches of the FEM using Abaqus®. The CAS approach based on linear wave theory and the CEL approach based on non-linear wave theory are used here to study the fluid-structure interaction (FSI) behavior of the tanks. Sloshing displacement, impulsive, convective, and total hydrodynamic pressures are investigated for varying geometries of the tanks. The small amplitude sloshing and hydrodynamic pressure responses are compared between the two FE-based, CAS and CEL approaches. The results obtained from the present FE-based analysis approaches are found to be in close agreement with the experimentally obtained seismic response in the 3-D cylindrical and rectangular tanks subjected to seismic ground motions. The ratio of peak sloshing height (h) to liquid height in the tank (HL) obtained in the cylindrical tank using the CAS approach is 0.0425 and that by the CEL is 0.039, whereas for rectangular tank it is 0.060 by the CAS approach and 0.046 by the CEL approach; thereby, signifying relatively small sloshing amplitude response. It is concluded that the non-linearity of the sloshing wave displacement does not play a significant role while calculating the hydrodynamic pressure distribution on the rigid tank walls.