Buckling analysis of large scale oil tanks with a conical roof subjected to harmonic settlement

This work deals with the buckling behavior of large scale oil tanks with a conical roof subjected to harmonic settlement. Firstly, the buckling behavior and the critical harmonic settlement of the tank with the conical roof for different wave numbers are analyzed. The results show that buckling occurs on the roof when the wave number is small, while it changes to the shell when the wave number is large. Also, for the original tank, the critical harmonic settlement decreases greatly for a small wave number, while the critical harmonic settlement decreases slightly for large wave numbers. Then, the parametric studies are conducted including the height-to-radius ratio, the radius-to-thickness ratio, the slope and the thickness of the conical roof. For the height-to-radius ratio, when the wave number is small, the critical harmonic settlement depends not only on the h/r ratio but also on the wave number. However, when the wave number is large, the critical harmonic settlement versus h/r ratio is monotonically increasing. For the radius-to-thickness ratio, for a small wave number, the critical harmonic settlement is not only related to the r/t ratio, but to the wave number as well. However, for large wave numbers, the critical harmonic settlement versus r/t ratio is monotonically decreasing. For the slope of the conical roof, when the wave number is small, in general, the critical harmonic settlement increases with the slope. However, when the wave number is large, the critical harmonic settlement is almost independent on the slope. For the thickness of the conical roof, for a small wave number, the critical harmonic settlement increases with the thickness of the conical roof. However, for large wave numbers, the critical harmonic settlement is almost independent on the thickness of the conical roof.