Rhei
Aerospace
- Oct 2, 2015
- 20
Hi,
I am running a non-linear transient analysis using SOL 129 and I was wondering, how can I be reasonably sure I have chosen the right DT value in the TSPENL card?
My excitation is a sine-sweep in the range 5-40 Hz and I am now using a DT = 5.E-4. I would say this is enough since it means I can see frequencies up to 1000 Hz (for the shannon theorem), which is well above my highest excitation frequency (40 Hz) and my resonance frequency (30 Hz).
The fact is that the run last for more than 7 hours so I cannot keep trying different values of DT to find the correct one. Is there a way to have an idea about the "correct" value to use?
What do I have to look for (in the f06 for example) to understant if it is working fine?
And more in general, what do I have to look for to understand if the overall non-linear set-up is fine? (for example, for what concern convergence criteria I tried using UPW and U only but I cannot see any difference in the response, does it mean it doesn't really matter the choice of the convergence criteria?)
Thank you
Regards
I am running a non-linear transient analysis using SOL 129 and I was wondering, how can I be reasonably sure I have chosen the right DT value in the TSPENL card?
My excitation is a sine-sweep in the range 5-40 Hz and I am now using a DT = 5.E-4. I would say this is enough since it means I can see frequencies up to 1000 Hz (for the shannon theorem), which is well above my highest excitation frequency (40 Hz) and my resonance frequency (30 Hz).
The fact is that the run last for more than 7 hours so I cannot keep trying different values of DT to find the correct one. Is there a way to have an idea about the "correct" value to use?
What do I have to look for (in the f06 for example) to understant if it is working fine?
And more in general, what do I have to look for to understand if the overall non-linear set-up is fine? (for example, for what concern convergence criteria I tried using UPW and U only but I cannot see any difference in the response, does it mean it doesn't really matter the choice of the convergence criteria?)
Thank you
Regards