topic Re: Instability in Robot Structural Analysis Forum

Instability

denis.lucey1 — Fri, 28 Apr 2023 14:15:08 GMT

Hi everyone,

Im making a model and getting a lot of instability in the middle of my structure i have moved the nodes in the middle around to try and fix this but still doesnt work. I have releases on the members too. Any help would be appreciated.

Re: Instability

Romanich — Fri, 28 Apr 2023 15:08:47 GMT

Hi @denis.lucey1 ,

Please zip and upload the model.

Re: Instability

denis.lucey1 — Fri, 28 Apr 2023 16:37:49 GMT

The model is attached to this

Re: Instability

Romanich — Fri, 28 Apr 2023 16:58:04 GMT

Just delete all releases for bars and everything should be ok.

Situation like this will lead to instability:

And why do you have supports at the top of the walls?

Re: Instability

denis.lucey1 — Fri, 28 Apr 2023 17:26:44 GMT

Ya I'll try that but i think that creates a bending moment at the support which is what I'm trying to avoid. Should the supports not be at the top cause theyre supporting the beam?

Re: Instability

Romanich — Fri, 28 Apr 2023 17:35:07 GMT

Hi @denis.lucey1 ,

It is enough to assign release to the bar in connection to the wall:

Re: Instability

denis.lucey1 — Fri, 28 Apr 2023 17:56:19 GMT

Ya there's still moments hogging over the supports with releases this wont happen. I'll just have to try get my head around it.