Whether to Model Equipments as Rigid or Pipe Element in C2

I need your views 'whether Columns/Exchanger's needs to be Modelled as Rigid Element or Pipe Element in C2.
I want to know Merits and Demerits of same.
Please also go thru page no. 3-12 to 3-16 of Application Guide (Caesar II).

Also wanted to know in details about Pump Modelling.

Whether to use rigid or pipe elements depends on the physical nature of the component that you are modelling. In the Pipe stress programme you are making a mathematical model of a physical system which to give you realistic results , should simulate the actual physical properties of the body.

Coming to modelling of exchangers and Columns,they can be simulated as Pipe bodies as modelling them with rigid elements will make them more stiff than they actually are.

Say a column: It is just like a pipe .However when modelling the column from its centerline to the wall, it is more prudent to model it as rigid element.The rest should be modelled as pipe.

Same logic is valid for modelling of exchangers.

However for a pump, the entire model ( from suction to pump centre and from pump centre to discharge ) should be modelled with rigid elemnts as only then they will have stiffness more than the associated pipe, which is actually the case.


A.BHATTACHARYA

STRESS ANALYST

BECHTEL CORPORATION

The "shell" of columns and exchangers should be modeled as "pipe" instead of "rigid", as this will allow the element to deflect if necessary - say due to wind loads.

As Anindya stated, the dummy elements used to connect to the "shell" should be rigid.