Buckling analysis of open top tanks subjected to harmonic settlement

This work addresses the buckling behavior of the open top tanks subjected to harmonic settlement. First of all, the buckling behavior and the critical harmonic settlement of an open top tank for various wave numbers are investigated. The results present that buckling occurs on the upper shell for a small wave number, while it changes to other places of the shell for large wave numbers. Also, with the wave number increasing, the buckling point is closer to the base of the shell. Besides, for the original tank, the critical harmonic settlement decreases greatly when the wave number is small, while the critical harmonic settlement decreases slightly when the wave number is large. Then, the parametric studies for the buckling behavior of the open top tank are conducted, composed of the height-to-radius (h/r) ratio and the radius-to-thickness (r/t) ratio. Regarding the h/r ratio, for a certain wave number, the critical harmonic settlement versus the h/r ratio is monotonically decreasing. Also, with the wave number increasing, the critical harmonic settlement decreases more and more slightly. Regarding the r/t ratio, for a certain wave number, the critical harmonic settlement versus the r/t ratio is monotonically decreasing. Moreover, with the increasing wave number, the critical harmonic settlement decreases more and more slightly. Finally, the buckling results of the open top tank are compared with that of the conical roof tank. The results illustrate that the open top tank can hold a larger harmonic settlement than the conical roof tank for no restraint from the roof for a small wave number. However, for large wave numbers, there is a small difference in settlement sustaining capacity for open top tanks and conical roof tanks.