Plastic Deformation of Beam Elements

[murcott]

I am trying to model plastic deformation of a beam model in FEMap. I have set the model up in the same manner described in the examples tutorial "Plastic Deformation of Rod - Nonlinear Material" which uses rod elements. Rod elements will retain the plastic deformation, but when I change them to beam elements, the plastic deformation is not retained and the mesh behaves elastically, even though the stresses exceed the yield of the material.

I understand that beam elements will not function as 'Non Linear Elastic' but should do under 'Bi'Linear' and 'Geometric Non Linear' settings.

Has anyone run a plastic analysis of a beam model in FEMAP before, and could they explain what I doing wrong or missing ?

Thanks

 

[rb1957]

maybe model your beam as two ROD caps and a shell web

another day in paradise, or is paradise one day closer ?

 

[FEMACAE]

For elasto-plastic analysis u will have to extrapolate the stress-strain curve by ramberg-osgood equation...for more detail u can visit

http://www.femechanalysis.com

 

[BlasMolero]

Hello!,
With the basic nonlinear module of NX NASTRAN (SOL106) for the CBEAM the only nonlinear material available is elastic-perfectly plastic. The material specified on a MATS1 Bulk Data entry should be elastic-perfectly plastic. Use of any nonlinear material other than elastic-perfectly plastic will give inaccurate results. And of course, only CBEAM element support material nonlinearities, the CBAR is not supported at all.

Best regards,
Blas.


~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

IBERISA
48004 BILBAO (SPAIN)
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http://www.iberisa.com

Blog de FEMAP & NX Nastran:

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[murcott]

Hi Guys,

Thank you for the help and suggestions. I'll try what Blas has suggested first, although I think i've tried using those material settings to no avail. Failing that, I'll try the approaches suggested by FEMACAE and rb1957.

Cheers.

Murcott