This is a finite element model of the lower half of a spherical LNG tank supported at its equator. The tank is filled to just below its equator. The weight of the LNG causes an axisymmetric stress distribution that, just below the equator, is meridional tension combined with hoop compression.
This prebuckling stress distribution in the wall of the tank gives rise to buckles that are longer in the meridional direction than they are in the circumferential direction, a kind of wrinkling with many circumferential waves.
The prebuckling load distribution in this LNG case is the "opposite" from that which occurs in the previously shown buckling of wine and water tanks under earthquake loading and buckling of conical water tanks upon being filled for the first time. In those previous examples of shell buckling we have meridional (axial) compression combined with circumferential tension, a prebuckling stress distribution that gives rise to buckles that are longer in the circumferential direction than in the meridional direction.
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