Nonlinear analysis of liquid-filled tank

Recent developments related to the analysis and design of liquid storage tanks are surveyed. Different aspects of the problem are examined. Background for finite element formulation is also outlined. A numerical tank model which accounts for the lateral pressure loading is developed to provide an understanding of this effect on the behavior of liquid storage tanks. This lateral pressure loading is simulated via ah equivalent hydrostatic approach in which the follower force effect is accounted. Results show that the tank model collapses at a critical load 20% lower than the classical prediction. It also shows that the axial stress is basically dominated by cos 6 mode. Higher order modes, are significant in the hoop stress profile which is nonlinear in character. The observed "elephant-foot buckle" and the "ovalling" response of liquid storage tanks in many tank failures during earthquakes can be predicted with these nonlinear methodologies.