ERROR # 5408 - No Structural modes have been found

ram_see_syn01
ram_see_syn01 Altair Community Member

I am building an input deck a bit manually for demonstration purpose of how FRA works. Attached is the deck I built (which is actually based on the training example available from Altair).

However, when I run this deck, I get ERROR # 5408

ANALYSIS RESULTS :
------------------

  
ITERATION   0
  
 *** WARNING # 3917
 No mode exists in the interval specified.
        subcase ID = 1
 minimum frequency = -1.0000e+01
 maximum frequency =  1.0000e+03
***************************************************
Beginning modal dynamic frequency response analysis
***************************************************
  
 *** ERROR # 5408 ***
 Aborting analysis because no structural modes have been
 computed in the modal dynamic subcase 1.
  
 This error occurs in module "mfrfdrv".

************************************************************************


I am awaiting the community's kind response on what is the issue with deck that is not running. 

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Best Answer

  • ram_see_syn01
    ram_see_syn01 Altair Community Member
    Answer ✓

    Hi Rajashri,

    Thanks for responding. It was not due to loadsteps/ load collectores. I fixed the error by removing out PARAM, WTMASS and increasing the EIGRL upper bound to 10000Hz. The error 5408 says there is no eigenfrequency found in the range specified.

Answers

  • Rajashri_Saha
    Rajashri_Saha
    Altair Employee

    I took a glance on your .fem file and found quite a number of mistakes in load collector creation.

    You have kept SPC, DAREA, FREQi in a single load collector which is not correct. You need to separate out each into different load collectors and call them in respective field while defining Load step.

    From the model I am assuming that you are doing the MFRF tutorial available in help page. Here is the link for it so that you can do the steps correctly.

    https://2024.help.altair.com/2024/hwsolvers/os/topics/solvers/os/modal_freq_response_flat_plate_r.htm

    Go through the steps and if you are still getting error let me know.

    Thanks

    Rajashri

  • ram_see_syn01
    ram_see_syn01 Altair Community Member
    Answer ✓

    Hi Rajashri,

    Thanks for responding. It was not due to loadsteps/ load collectores. I fixed the error by removing out PARAM, WTMASS and increasing the EIGRL upper bound to 10000Hz. The error 5408 says there is no eigenfrequency found in the range specified.

  • Rajashri_Saha
    Rajashri_Saha
    Altair Employee

    Yes, I agree to your point. PARAM, WTMASS should be removed. Before doing FRF , always conduct a modal analysis to see the natural frequency for the component/assembly. You will get an idea of frequency range. But still regarding the set up, do not keep SPC, DAREA, FREQi in one single load collector.