Error in dynamic EQ calculation

ROHR2 Dynamic calculations, questions and discussions
ROHR2stoss - Structural Analysis with Dynamic Loads using Direct Integration
Antworten
Benutzeravatar
r2user
Beiträge: 144
Registriert: Mi 14. Sep 2011, 10:18

Error in dynamic EQ calculation

Beitrag von r2user »

Good morning,

I have problem with Fixpoints on pipes, when I do calculation with earthquake static case and earthquake dynamic case, the dynamic calculation is canceled.
Here are the error messages:
error.png
Could you explain me where is the problem and could you give me some procedure for solving.

Thanks
Sie haben keine ausreichende Berechtigung, um die Dateianhänge dieses Beitrags anzusehen.
Benutzeravatar
rohr2support
Beiträge: 455
Registriert: Mi 14. Sep 2011, 08:23

Re: Error in dynamic EQ calculation

Beitrag von rohr2support »

Hi

The problem is that there are no eigenvalues up to the cutoff frequency of 25 Hz. The first eigenvalue of this system is at 58Hz.
If you want to do a dynamic analysis you should at least have enough eigenvalues so that you can see how most of
your mass is oscillating. Or if your system is very stiff (as in your case) you can just make a static analysis.

If you change the max cutoff frequency in the ROHR2 task in the load case Eigenvalue to 100Hz it works.

Best regards
Antworten