Greetings dear collegues,
my question deals with representation of "directional" mass and damping in ANSYS Worbench.
In detail, I need to represent the added mass and the radiation damping of an offshore structure and I have find out that commands MATRIX27 and MASS21 may serve to this purpose. Additional mass, indeed, are not sufficient, since they would have the same value in all the three directions, while added mass depends on x-y-z.
Unfortunately, I am not an expert user of Mechanical APDL module of ANSYS and I need to work only with Workbench, where such instructions may be given through the "Command" item, whitin the "Solid Body" tree.
May someone give me some simple explanation on the instructions to give in the "Command" text (e.g. a template) to represent a mass and/or damping symmetric matrix associated to this body'?
Thank you very much in advance,
Carlo
Hi Carlo,
I have got a good example for you to share... think this will resolve your issue...
https://www.simutechgroup.com/tips-and-tricks/fea-articles/148-fea-tips-tricks-rotation-force-point-mass
Dear Claudio Pedrazzi
and Arun Patil ,thank you very much for your precious help and for the time you dedicated to my problem.
I will check in depth your suggestions and I am sure they will give me significant help for my model.
I will let you know my outcomes, as soon as I manage to understand everything.
Best regards and thank you again,
Carlo
Dear Claudio Pedrazzi
,I tried to implement your code on a sample file and it seems to work well for my application with the command MASS21.
I guess that, following the example, the added mass is concentrated in the middle point of the named selection (as it is found by the mesh) and it works as if it was rigidly connected to it.
I would like to thank you very much for your very precious help.
I still have some small doubts and I would be very thankful if you could clarify these few points to me whenever you will have time:
1) how to include mass moments of inertia in the MASS 21 command? I guess I should use ARG4-6 for definition but then I am not able to insert them in the script
2) if i wished to use MATRIX27 to add also damping how would the input command change? And how can I give more than 9 inputs in this case since number of "ARG" intems is 9?
Best regards,
Carlo
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