Modal effective mass- coordinate system

Hi all,

I'm performing a modal analysis and, in order to get modal effective mass fraction, I used the Param, Effmass command.

The output file printed out the modal effective mass fraction based on the origin of the basic coordinate system.

My model is a conic plate and I'd like to get modal effective mass fraction in a different point and in a different reference system other than basic coordinate system.

Is there any way to get this???

Thank you so much

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Joshua Pennington

Hi,

Can you set the nodal reference and displacement to a local coordinate system and rerun?

First create the local system, then assign.

Staedtlerp

Hi,

thank you very much for your reply. I will try to follow your advice and I will let you know.

Do you know if it is possible to plot on Hyperview or Hypergraph the modal effective mass for each mode??

Thank you.

Thomas Quenaon_21507

Hi,

For your application there is no option in OptiStruct to specify a coordinate system for the EFFMAS calculation. The only way to express it where you want it to translate the model to position the center of gravity of your model at the location you want. I'll contact the developers to see if it can be improuved.

To help you create bar charts you can use in addition the OUTPUT,HGEFFMASS creating an HyperGraph chart for effective mass calculation.

BR-

Thomas