Hi stress engineers,
I am reading the Coade Pipe stress analysis notes. i am confusing the statement regarding the node numbers in jacketed pipe, it states "The first and last node numbers of the outer pipe should then be changed to the same node numbers as those of the first and last point of the inner pipe-this serves to connect the inner to the outer pipe".
Does anybody who can explain this statement?

In case also of the end cap location, do i need to consider that as restraint (anchor type) with connecting node (ex. 10 Cnode 1010)?

I appriciate all your responce..!

regards,
Nald

Hi Nald

Jacketed pipe is concentric with core pipe. jacket is attached with core by some anchor & some spacer.
First model the core pipe. then copy that file, another model will be created in same location than previous one.
Now for jacket diameter, thickness, pressure , temperature, insulation density need to change manually.
So two concentric pipe model will be there in same location but both are free with each other in stress point of view.

To connect both the model we have
1) Either change all anchor to same node number
2) Or connect all anchor with Cnode anchor.
3) For spider rest & guide with gap may be model with Cnode.

That will make a joint system of core & jacket pipe to run for stress.

Regards

Habib

Shr,
Thank you for your informations it help me a lot.
Regarding also the output of the summary of restraint.
Most of the end cap connection which I consider it as anchor restraint with connecting node,
Does it acceptable that the loads of the connection cap are big loads, which i suppected uncommon?
Do i need to confirm the vendor of the jacketed pipe regarding the output result of my analysis?
in configuration set-up, if I change the Add F/A in Stress Tab to default
Does it affect the value of restraint output?

Please share your idea, i am wondering the result of my analysis.


Regards,
Nald

Hi Nald

Generally operating temperature difference between core & jacket pipe should not be more that 20 to 30 degC.
This temperature difference is also produce high axial load at Core-jacket anchor interface.
Caesar will not perform local stress analysis for that it will show only high axial load. You have to make a separate local analysis ( may be in excel sheet) for the integrity of the system.
This may be done at the time of deciding core & jacket thickness.
Once it is fixed then there should not be any problem, still for all individual calculation separate local stress check for maximum load is recommended to ensure safety of the system.

In operating condition there should be very small temperature difference between core & jacket pipe since core pipe also experience high external temperature , same as jacket.
But we need to design the system for worse possible case hence have to consider differential of core & jacket temperature for local analysis for local stress check.


Regards

Habib

Shr,
so after finally decided the core and jacket thicknesses,
that is the time that i will inform the vendor.
Please correct me if i misunderstood?




Regards,
Nald

Dear Nald ,

could you please send me that pipe stress analysis notes. here is my id vikasn@klgsystel.com.


thanks in advance.

Hi Nald

Jacketed piping can be site fabricated unless it is a "Vacuum jacketed" piping.
Stress engineer has to check overall flexibility & local stress checking for normal jacketed piping.

Regards

Habib

Shr,
Thank you so much for your ideas.


Regards,
Nald