Linear buckling with an unsymmetric T - extrusion

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

Hi there,

 

i tried to model a linear buckling analysis with an unsymmetric T - extrusion. The solution is far away from the solution calculated with hand:

 

HM solution with load applied to the shear center: 5543 kN

HM solution with load applied to the extrusion center: 5543 kN

 

Calculation by hand: 8980 kN for euler case 2

Calculation by hand: 2328 kN for 'drill-buckling' (don't know how this is called in english-> german: Biegedrill-Knicken)

 

So why the solutions are so off and why the solutions for shear- and extrusion center are the same? If the load isn't applied to the shear center the unsymmetric extrusion should also drill-buckle which leads into much less buckle load.

 

I added the 2 FE-models (shear center and extrusion center)

 

Thank you for your help :)/emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20'>

 

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2018

    Hi @PuddingBaer91

     

    Thank you for sharing the files. We will check and get back to you soon, 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2018

    @PuddingBaer91

     

    I think I am missing something, I don't see any difference in both the models. 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2018

    Thank's for investigating. Please look at the Last discharge point. In one model it's the shear center and in the other model it's the extrusion center.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2020

    Hi,

     

    Can you try these models?

    Unable to find an attachment - read this blog

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2018

    Hi,

     

    Can you try these models?

     

     

    i opened these models but don't know what to do with it? You only changed the extrusion?

    Unable to find an attachment - read this blog

  • tinh
    tinh Altair Community Member
    edited June 2018

    Hi,

    I saw you use PBEAM property. You should not use it.

    Could you try defining property with 'PBEAML' card image and rerun?

     

    and, to change load position, you should use offsets on cbeam elems

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2018

    opened these models but don't know what to do with it? You only changed the extrusion?

    I have given an offset for both the cases on beam elements so that load is applied on respective centers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2018

    Thank you very much :)/emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20' /> I will try this later today and report. Could you please tell whats the difference between PBEAM and PBEAML ?