ansys steel frame with shell281 elements

[Ani1989]

Hi everyone,
I am using ansys to model a 3d steel frame with perforated beams. the elements are modeled using shell281
I want to define the connection between the beam and column as a moment frame with semi rigid connection.
Because when I run the nonlinear analysis it is says poorly connected.
I have attached an imagine of my frame.
Thank you

 

[IanME]

Have you tried modelling the perforated beams as solids? Is that too many elements for you to consider?

What connection element are you using to connect the beams? I would consult the ansys contact technology guide :

http://www1.ansys.com/customer/content/documentation/120/ans_ctec.pdf

Just some things for you to consider.

Hope this helps.
-Ian


"All models are wrong, but some are usefull" - George E. P. Box

 

[Ani1989]

Thank you !
I have to model it with shell elements.
I have used the contact properties, surface to line, but it still says when i run it that my model is poorly constrained ??

 

[IanME]

"I have to model it with shell elements. "

Okay.

"I want to define the connection between the beam and column as a moment frame with semi rigid connection. "

You could try using a non-linear rotational spring with defined resistance to achieve this 'semi rigid' connection. My other thought is to model the connections with short stubby BEAM188 elements and define the stiffness there.

Hope this helps,
-Ian

"All models are wrong, but some are usefull" - George E. P. Box