Dynamic buckling beam - imperfection

paula94
paula94 New Altair Community Member
edited October 2020 in Community Q&A

Hello, 

 

I work on a vehicle suspension optimization. For that purpose I need to perform a dynamic buckling analysis of a tube (meshed by 1D beam elements). I have already performed static analysis, static buckling and modal analysis and the next step is performing dynamic buckling with force impulse. In order to perform this analysis I need to apply an imperfection of the geometry (initial deformation). The imperfection is supposed to be the first buckling mode from static buckling and the corresponding displacements are assumed as a coefficient 0.01, 0.05 etc. Therefore my question is whether it is possible to apply such buckling mode imperfection in OptiStruct, if so where I can find this option?

 

Thank you for any help in advance.

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Answers

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited December 2019

    Hi,

    buckling instability causes convergence difficulties for implicit methods. Therefore I suggest using Radioss explicit solver instead following this procedure:
    1.perform modal analysis in Optistruct
    2.in postprocessing create a derived load case>linear superposition>use small scale factor (1e-2 to 1e-3)


    3.export the deformed shaped.


    4. import the deformed shape into Hypermesh Radioss user profile and set up non-linear buckling analysis.

     

    By using the deformed shape obtained from the modal analysis the structure will have geometry imperfection triggering a buckling pattern consistent with modal and linear buckling analysis.

     

    Note:1D element idealization will not capture the true buckling behavior of the thin-walled structure. Therefore 2D shell elements should be used instead.  

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