Sir,
I have to model a Propane sphere in CAESAR II , Can we model it as weightless rigid as that of any column or other vessel. I am in doubt as the surface of a sphere is curved at every point so diametrical expansion will be a point to be considered.

hi,
why you want to model it in the first place? For pipe connectins?
regards

I have to analysis the sphere inlet and outlet lines. Outlet lines are connected to Pumps.

Addition to that I wan to know modelling a Sphere as that of other vessel is correct or not or shall I calculte displacement at nozzle and complete my calculation.

You only need the nozzle / shell attachment identified in your piping model. There is no reason to attempt to model the sphere, it's only a set of boundary conditions so far as the piping is concerned.

Expansion / contraction at the nozzle will be vertically, approximately from the leg atttachment elevation and radially, from the central vertical axis.

Dependent upon your shell thickness and nozzle size there may be some flexibility worth including. A proper figure for this would have to come from an FE analysis, but you could get some idea by approximating the vessel as cylindrical and using WRC297.