Radioss Bulk NLGEOM How to combine Forces (GRAV,...) and linear increasing displacement?

Rahul_P1
Rahul_P1
Altair Employee
edited October 2020 in Community Q&A

Hi,
I like to give to a structure GRAV load and additional enforced displacement.
All calculatet with Radioss Bulk data for large displacements - NLGEOM
To see model: rename attached .jpg to.hm
All displacements ( zero and enforced ) are in the same load collector.

The results seem to be wrong- the model part without enforced displacement should have max deformation ~ 131mm.

Will it be better to increase the enforced displacement linear to the end of calculation?
How to manage?
( SPCD, TABLED1, NLOAD, NLOAD1 ) ?
icon_smile.gif Can you send me a link to a tutorial combining GRAV and SPC for Radioss / bulk / NLGEOM?
or
icon_biggrin.gif Can you correct the given model and send it back?

ThankX Dirk
0674s-ruler_NLGEOM_GRAV_add_spc.hm_.jpg
ojw88-Ruler_GRAV_DISP_wrong_result.JPG

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Answers

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited November 2014

    cae_1_rfh,

    Your initial set up was correct. You cannot use dload to combine gravity load with spc or spcd.

    When you give enforced displacement within the spc itself and refer grav in the LOAD card, you are in fact combining enforced displacement and spc. This is what you have done, these results if they do not agree with your experiment/calculation etc it is perhaps due to a different discrepancy while modelling.

    When you need to use nload it should be as in this attached deck

    you will be creating an nload 1 for grav (you can give a time function here if necessary, using tabled1)
    another nload 1 for spcd (if you are defining enforced displacement via spcd)
    combine these nload 1 cards in an nload and refer this nload in the nload filed of your nlgeom loadstep

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited November 2014

    Thank you!!
    I can follow your explanation. icon_biggrin.gif

    I will try some variants,...

    Dirk

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