Different Results for Support Loads?

Frequently asked questions
Antworten
Benutzeravatar
r2user
Beiträge: 144
Registriert: Mi 14. Sep 2011, 10:18

Different Results for Support Loads?

Beitrag von r2user »

Dear Support Team

I have done a small result comparison between ROHR2 and CAESARII.
In that small model (just a bend with fixed points at both ends) I get exactly the same stress results but different support loads.
They are lower in ROHR2 than in CAESARII.

Can you look in to that?

Best regards
Zuletzt geändert von r2user am Mo 19. Sep 2011, 15:08, insgesamt 1-mal geändert.
Benutzeravatar
rohr2support
Beiträge: 455
Registriert: Mi 14. Sep 2011, 08:23

Re: Different Results for Support Loads?

Beitrag von rohr2support »

Can you check your settings for the load cases?
Youngs.png
Did you use the same settings in ROHR2 and CAESAR2?

If you use the youngs modulus at operation conditions, the piping system is slighly more
flexible. You can then see the real deflections and support loads.
The stress code requires you to use the cold youngs modulus.
Therefore in ROHR2, if you select the youngs modulus at operation temperature
the stresses are multiplied by a factor Ycold/Yhot which compensates the stresses.
This is not done for the support loads.
If on the other hand you use the cold youngs modulus for your load case calculation
then defelctions are underestimated, support loads are overestimated and you stress
analysis is according to code without any correction factor for the youngs modulus.

Best regards
Sie haben keine ausreichende Berechtigung, um die Dateianhänge dieses Beitrags anzusehen.
Benutzeravatar
r2user
Beiträge: 144
Registriert: Mi 14. Sep 2011, 10:18

Re: Different Results for Support Loads?

Beitrag von r2user »

Dear support team

You were right: I used the youngs moduls at 20°C for the CAESAR2 model and the youngs moduls at operation conditions (220°C)
in ROHR2.
When I select "Y modulus at assembly temperature" I get the same results for stresses and support loads with both programs.

Thanks a lot
Antworten