topic Re: Mode shape vectors in Robot Structural Analysis Forum

Mode shape vectors

sergey.churilov — Thu, 26 Apr 2012 10:29:11 GMT

Hi to all,

How do you present mode shape vectors from each mode after performing modal analysis?

I would like to compare the mode shape vectors from numerical analysis with experimental analysis and establish the Modal Assurance Criterion (MAC).

Re: Mode shape vectors

Anonymous — Thu, 26 Apr 2012 10:38:19 GMT

Do you mean the mode shape diagram?

Or a numerical representation?

Re: Mode shape vectors

sergey.churilov — Thu, 26 Apr 2012 10:44:28 GMT

Numerical representation with values.

Re: Mode shape vectors

Artur.Kosakowski — Thu, 26 Apr 2012 11:00:06 GMT

Press the RMB on the table with results of modal analysis and select table columns. Switch to the Eigenvectors tab.

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

Re: Mode shape vectors

Anonymous — Tue, 18 Sep 2012 12:01:50 GMT

i didnt undesrstand what is RMB .in modalanalysis environment i am getting only frequency results. i cant see any table. i need to have mode shape vectors .kindly help me with this

Re: Mode shape vectors

Rafal.Gaweda — Tue, 18 Sep 2012 12:07:22 GMT

RMB - right mouse button

Click on table using right mouse button then select Columns....

Re: Mode shape vectors

Anonymous — Tue, 18 Sep 2012 15:51:57 GMT

i am working in autodesk inventor for modal analysis.i got first 10 modes.but i need to have mode shape vectors to compare with experimental results.i am attaching image of my result.please suggest looking at the figure.

Re: Mode shape vectors

Rafal.Gaweda — Wed, 19 Sep 2012 09:10:08 GMT

This is Robot forum, not Inventor.

Inventor http://forums.autodesk.com/t5/Autodesk-Inventor/bd-p/78

Re: Mode shape vectors

Anonymous — Fri, 11 Jan 2013 13:33:55 GMT

To vertify my structure i have used matlab and plottet the eigenvectors. I am trying to compare the results from robot with the results from matlab. is there a smart way to get the eigenvectors ou from robott.. all i seem to get are -0 +0 and 1 -1 ?

Re: Mode shape vectors

Anonymous — Fri, 11 Jan 2013 13:39:25 GMT

I was also wondering if Robot take into acount crackling of the concrete by code reduction factors for shear and flexular deformation when preforming a modal analysis?

Re: Mode shape vectors

Rafal.Gaweda — Fri, 11 Jan 2013 13:43:52 GMT

To vertify my structure i have used matlab and plottet the eigenvectors. I am trying to compare the results from robot with the results from matlab. is there a smart way to get the eigenvectors ou from robott.. all i seem to get are -0 +0 and 1 -1 ?

See below

Re: Mode shape vectors

Rafal.Gaweda — Fri, 11 Jan 2013 13:47:21 GMT

I was also wondering if Robot take into acount crackling of the concrete by code reduction factors for shear and flexular deformation when preforming a modal analysis?

No , reduce E or section properties by your own

Example:

Re: Mode shape vectors

Anonymous — Wed, 05 Jun 2013 11:30:47 GMT

Regarding the Eigenvectors, what is the normalization criteria used? Are all the components of the eigenvector normalized individually, or are they normalized relative to eachother? If they are relative, how is the relation between length components and rotation components taken into account?

Thanks,

Jose

Re: Mode shape vectors

Pawel.Pulak — Thu, 06 Jun 2013 09:05:11 GMT

The components of the eigenvector are normalized relative to each other.

The relation is "unit independent" because values of rotation components correspond to tangents of appropriate rotation angles.

Regards,