Pages 103-112
Moss type tank system consists of a spherical tank and a cylindrical supporting skirt. The spherical tank is an unstiffened thin shell structure with large R/t and the plate thicknesses are determined by buckling strength except the equator and tank bottom. The skirt is a cylinder stiffened by vertical stiffeners and rings except that the top part is unstiffened. The geometry determined taking the thermal deformation and various loads into consideration. The buckling strength is also the most important factor for the skirt. It is well known that buckling strength of spherical and cylindrical shells is highly sensitive to structural imperfection. Therefore, it is very, important to accurately predict this reduction factor due to the initial imperfection (imperfection factor) in order to establish reasonable safety factors and production talerances. This paper proposes design formulae for buckling strength of spherical tank and cylindrical skirt including the imperfection factor after investigating the effect of initial imperfection based on some papers previously published.
