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[Abaqus]LTB prediction using 3D beam elements

Submitted by Staszkinson on

Hello,

Is it possible to predict value of lateral torsional buckling moment using three dimensional beam elements in Abaqus? A lot of analysis is performed using shell elements. I want something easier for now and later I'm going to do my research on shell elements too.

What things should I focus on modelling an I-beams using beam elements in Abaqus?

The problem is that my actual results from abaqus using beam elements are lower about 20% then I expected.

 

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Akumar

To get Pcr for LTB, use open section elements (B31OS) in abaqus. You will need to enter warping constant & sectorial moment of inertia and related stuffs (Cw and GammaW)...

Only open section elements can predict LTB and warping :)

For post buckling response,  I am not sure how accurate these elements will be. But Euler Buckling Load, it's quite accurat.

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The world started with 0, is progressing with 0, but doesn't want 0.

Tue, 10/23/2012 - 17:59 Permalink
Staszkinson

Hello,

I have made a simply experiment.

In the first case I have analysed simply supported beam(I Shape, B32OSH elements, nonlinear analysis) with bow imperfection(only TRANSLATION, without crosssection twist).

In the second case I have analysed the same beam, with bow imperfection(TRANSLATION + TWIST) form buckle analysis(used *imperfection command).

In both cases the magnitude of imperfection was equal.

In both cases I have received the same value of ultimate strength of my beam.

I expected that analysis with this second type of imperfection give me a little bit higher results but they're equal.

Is this connected to Wagner effect in Abaqus? 
Sat, 11/03/2012 - 16:15 Permalink
LT21

Hello,

I have found this discussion about beam elements and wanted to ask if you may could help me?

I am working on a project with Abaqus and have got a problem by applying torsion/ twist to a beam element. Now I have found this comments and maybe you can help me.
The structure I would like to create is a ligament consisting of an individual number of fibres. Each fibre is pretwisted by 45 degrees or more. I would like to use for the fibres beam elements because on this way I have not got problems with the long time a calculation of volume elements would take furthermore I have found in the Abaqus manual information concerning a pretwist or torsion moment which you can apply to beam elements by using a predefined field but I do not really understand how that should work.
 
If you have got any idea it would be great if you could help me.
Iam looking forward to your answer!
Mon, 09/08/2014 - 15:38 Permalink