How to obtain relative displacements in direct transient analysis?
Hi,
I'm performing some linear transient analysis, I was able to get good results with the modal transient analysis. But if I try to set the same problem as a direct transient problem I get a rigid motion of the plate. I was having the same issue with the modal transient that was solved using the PARAM ENFMOTN set to REL.
Is there something like that for the direct transient analysis or I can only perform a post process operation and subtract the SPCD displacements "by hand"?
thank you for every help, find attached the fem files of both analysis.
Antonio Tommasuolo
Best Answer
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In fact, modal trasnient is better in this case, as it could directly get rid of this.
not sure if this helps, but in physical test, a pre and post correction signal is applied to compensate these high displacements and get rid of the undesired motion (which is natural due to the enforced acceleration profile (half-sine)).
I also saw once that we could apply a gravity load on the opposite direction to stabilize the motion. I never tried this, but might be worthy trying.
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Altair EmployeeAnswers
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In fact, modal trasnient is better in this case, as it could directly get rid of this.
not sure if this helps, but in physical test, a pre and post correction signal is applied to compensate these high displacements and get rid of the undesired motion (which is natural due to the enforced acceleration profile (half-sine)).
I also saw once that we could apply a gravity load on the opposite direction to stabilize the motion. I never tried this, but might be worthy trying.
0