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Analysis error: USER FATAL MESSAGE 4405 (PRTPRN) NO EIGENVECTORS COMPUTED

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FcoBorja_95

Aerospace
May 10, 2017
1
Hello, I am doing a structural analysis with Nastran-Patran for my final project degree and I´m having some problems with the analysis. This model that I´m analyzing has around 7000 elements and I have been trying a lot of time to figure out what might be the error but I cant find it. I will really appreciate your help, I am short of time and getting so desperate with these problems.[morning] Here is the main error from the F06 file with the information of the analysis (I think is the main because is the first fatal message of all the document):
*** USER FATAL MESSAGE 4405 (PRTPRN)
NO EIGENVECTORS COMPUTED FOR COMPONENT MODE SYNTHESIS OR SYSTEM SOLUTION.
The complete f06 and Bdf files are not allowed to be uploaded directly to the forum, but I can send to your email if you are interested.
Thank you very much![wink][bigears][2thumbsup]

 
 http://files.engineering.com/getfile.aspx?folder=a4e5fab2-0454-481f-913c-fec2d54e9444&file=chasisd_analysis2.f06
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From your f06 file ,there is a UWM just before the UFM which says:

*** USER WARNING MESSAGE 6636 (LNNRIGL)
NO MODES EXIST IN THE INTERVAL SPECIFIED ( 9.9999994E-01 TO 1.9999999E+03 HZ).


If you're using the V1 and the V2 fields on the EIGRL card then I suggest remove them and use the ND field which instructs NASTRAN to find the first ND eigenvalues. Start with let us say ND=2 and see if the frequencies/mode shapes computed are in-line with what you would expect.

Assuming your modeling is right and units consistent you seem to have a very stiff structure.
 
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