harmonic analysis

[colastanarobo]

Hi,

I introduced  the vibration of a machine (frequency=10Hz) : HARMONIC ANALYSIS.

The problem is that the results are not clear: there isn't load combinations  with harmonic

Can you explain me this type of analysis

Best regards 

[Rafal.Gaweda]

I do not understand. Please explain.

[colastanarobo]

I understand that with harmonis analysis we cannot generate automatic combinations, that's it?

so we do manuals comb

[Artur.Kosakowski · Accepted solution]

You can provided you assign the nature to the harmoinic case.

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[colastanarobo]

it's only when we use eurocode as code

[Rafal.Gaweda]

Why? It works for CM66, and most likely for all other codes.

[colastanarobo]

Hi,

you're right

Thank you

[colastanarobo]

I come to ask a question about the reactions caused by harmonic analysis, why the values are null?

[Rafal.Gaweda]

Have you applied any load to Harmonic case?

[colastanarobo]

please, see this file

[Artur.Kosakowski]

As written by Rafal; add some load in case 21. You need to have some load that you want to apply in 'dynamic' way.

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[colastanarobo]

ok, what about (masses),I need to convert the masses dynamic or overall mass or harmonic, this detail isn't clear

[Artur.Kosakowski]

If you want to treat load defined in other load case as mass use the load to mass conversion. You can also use the added masses option if you want to add additional mass on the model. 

http://docs.autodesk.com/RSAPRO/2014/ENU/filesROBOT/GUID-FEC73829-9EDF-406B-9BAB-4A9201A32B0C.htm

http://docs.autodesk.com/RSAPRO/2014/ENU/filesROBOT/GUID-293A6BC3-EBE2-480B-921C-55FE7FB9DE2C.htm

http://docs.autodesk.com/RSAPRO/2014/ENU/filesROBOT/GUID-0F3E4B20-E266-4AFE-A7D8-12669751495B.htm

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[colastanarobo]

Hello Artur,

These loads are estimated based on equipments in the hangar? that's it? 

[Artur.Kosakowski]

I'm not sure if I understand the question. Which loads do you mean exactly?

[colastanarobo]

the loads in  harmonic case 21

[Artur.Kosakowski]

This is the dynamic load you assume as changing value in time e.g.  the moving / rotating part of  an engine.

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[colastanarobo]

so we must search in the specifications notes

[colastanarobo]

Iam sorry, i mean the specifications notes of this project

Thank you for all

[colastanarobo]

Hello Arthur,

I have not found the value required for the harmonic load calculation, will I be able to change the type harmonic FRF ???
what is the difference between harmonic and harmonic FRF?

Thank you in advance