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Error #179

Smackeroonies · 2025-05-27T15:01:53+00:00

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Smackeroonies

Description: I'm doing a torional Stiffness study of a monocoque, I belivie I've setup the model correctly following this tutorial https://www.youtube.com/watch?v=U2cJpttNK2c but I keep getting the error #179.

*** ERROR # 179 *** The dependent d.o.f.s of multi-point constraints produces a singular matrix. This may be caused by a circular dependency in which a d.o.f. is indirectly dependent upon itself.

I've tried editing the rigid bodies and double checked all the RBE2's and believe they have been done correctly so not really sure how to fix this error.

Any support would be very much appreciated.

Thanks,

Sam

Product/Topic Name : Hypermesh

Torional Study 1.hm

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Jason_Craanen

What version of Optistruct are you using?

It runs for me without issue in 2025.0

Smackeroonies

Thank you for your help, I'm using 2024.1 with student licence but don't know if that makes a difference.

Many thanks,

Sam

Jason_Craanen

Perhaps a node limit limitation? Your model is quite big. You could probably coarsen it quite a bit and still get reasonable results

https://web.altair.com/altair-student-edition

Smackeroonies

I made the mesh coarser reducing the number of elements from around 900k to 50k but still getting the error #179. The error could be coming from how I'm running my .fem file on the solver. I'm currently just pressing the ANALYZE button in the ANALYZE tab and then running the input .fem file created. Do you have an idea of how this could be going wrong?

Jason_Craanen

I see the same message in 2024.1, but not in 2025.0. Possibly a resolved issue?

Otherwise here is the specific error reference

https://help.altair.com/hwsolvers/os/topics/solvers/os/error_msg_database_intro_r.htm#error_msg_database_os_ts_concept_kn3_44m_y3b__error_msg_database_os_ts_section_qyp_ctl_p2b

Smackeroonies

I'll try go download 2025.0 and see if it work.
Thanks,

Sam