Hi Richard,

Just want to ask the approach for modeling jacket pipes with different material?
On my case the inner pipe is a stainless steel and the outer pipe is a carbon steel, I have already modeled this case and the resulting axial restraints is huge.

Hope you can help me with this.

Thanks,

There is no difference in modelling tech of jacketed piping with same material or different material. The huge axial load (assumed at core jacket connection) will be because of differential thermal expansion (due to different material and different temperature of core and jacket). You need to check axial stresses in piping (Automatically done by Caesar II as per applicable code) and weld strength check at core-jacket connection. In addition one should check buckling in piping system. Bucking needs to check manually as Caesar or any other Pipe stress software is not capable of checking buckling.

There is jacketed pipe model included in the Examples folder built with your CAESAR II installation. (Click on the "Examples" button in the "Open File" window.)
The key with jacketed systems is to get the spacers modeled correctly (using Node/CNode restraint pairs) to keep the core & jacket lines co-linear. It will be up to you to model other restraints where the core pipe actually "clashes" with the jacket (another restraint between nodes but with a gap).