[MBDyn-users] Static Analysis
David Cross (Civ, ARL/VTD)
david.m.cross2 at us.army.mil
Fri Jul 9 15:43:25 CEST 2010
Thank you. That should help me.
Another question...Im modeling flapping wing dynamics, and I am exciting
motion at the natural frequency whose mode shape corresponds most
closely to a flapping motion. I was wondering if there is a way to
prescribe proportional damping...say 1% of the structural stiffness??
Thanks again for all of your helpful advice. Regards,
masarati at aero.polimi.it wrote:
>> please always reply on the list.
>> The issue is strange, during static analysis the derivatives phase
>> should be' skipped (as far as I know).
> Derivatives are always performed. However, it is correct that for static
> analysis they may pose some issues. What you can do is either:
> - make sure the model is initially unloaded (at T = initial time), and
> load grows regularly to its final value; or
> - increase "derivatives tolerance" above the error that's computed during
> this phase.
> The latter approach is not that clean, resulting in some "fake" transient
> taking place from the first step on (since the model is static, so the
> transient would be purely numerical). However, a well-behaving model
> should recover in just a few steps.
> Cheers, p.
> MBDyn-users mailing list
> MBDyn-users at mbdyn.org
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