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ERROR # 5408 - No Structural modes have been found

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.

Bracket_FRA_1.fem

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Accepted answers

ram_see_syn01

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.

All comments

Rajashri_Saha

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

Rajashri_Saha

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.