Linear Buckling problem

[ianrhale]

Hi all,

I am trying to run a linear buckling analysis on the attached model, and it is all working. What i want to do is release the 'wing' braces, that is the diagonal brace at each level, to have a pinned joint at the junction with the tower. This wing brace has a horizontal fixed, vertical free support at its other end (ie a vertical roller). As soon as I release the brace at the tower end the analysis will not run. I think I am correct in releasing Z and Y at the end of this member so that torsion remains fixed, but I can't get the analysis to complete. I think the fixed joint might be giving me slightly high results.

Can someone give me a pointer why it wont run?

Thanks, Ian.

[Rafacascudo · Accepted solution]

I didn't check your model (on cellphone) but in the picture you sent you don't have vertical uz support outside the building for your braces. So , if you release the moments in the connection with the building , the braces will become unstable. Probably you are getting instabilities warnings for these horizontal brace supports in the Uz direction.
Try setting these braces as truss bars (geometry/additional atributes/advanced bar properties) and then set those brace supports as totally fixed supports

[Artur.Kosakowski]

Hi @ianrhale

Has the solution proposed by @Rafacascudo (thank you) worked for you?

[ianrhale]

Hi guys,

Sorry for not getting back to you, I have been away. I have a few more questions but will think it over in the next day or two and will report back. Thanks!

[ianrhale]

Artur & Rafael,

It has taken me a while to get back to this, but I just wanted to say I have been through it and can see the issue, I have no more questions.

You help is appreciated as always.

Thanks,

Ian.