Seismic Coupled Modeling of Axisymmetric Tanks Containing Liquid

Abstract

Research in seismic numerical modeling of liquid‐storage tanks has been concentrated on tanks with single curvature, such as cylindrical tanks. This paper outlines the development of a numerical model for the seismic analysis of tanks with single and double curvatures, which is achieved through the use of a combined finite‐element‐boundary‐element numerical procedure. The coupled seismic liquid‐shell interaction problem is solved using a shell finite element for the tank structure and the boundary‐element method to model the fluid region. The boundary‐element equations for the liquid region are used to obtain an equivalent finite element fluid mass matrix. This equivalent fluid mass matrix is then combined with the shell structure mass matrix and the coupled equations of motion are then solved. The computer program developed can handle both single‐ and double‐curvature axisymmetric tanks such as cylindrical tanks and spherical tanks. Free‐surface sloshing of liquid and tank‐wall flexibility are included in the model. Frequency‐domain analysis is required if sloshing is included.