Time varying loads NLGEOM analysis

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

Hye there,

 

I'm a beginner user of the Hypermesh. I want to setup an analysis of a panel dentability simulation, using Optistruct.

The load is applied via a ball indenter, with an initial 1mm gap between the panel and the ball indenter. The load of 200N applied perpendicular on the panel, and has to simulate a push/release action, so that a maximum and a permanent deformation of the panel can be determined.

 

Model setup done:

i)   Since the panel will undergo plasticity and the load varies over time, I set the analysis for a NLGEOM loadstep.

ii)  A contact interface between the ball indenter and panel was generated. PCONT properties was used to replace the contact's property option. PCONT properties with active GPAD_OPT and PCONTX (STFAC=0.01 & GAP=0.5)

iii) A TLOAD1 was setup, with the TABLED1 with values [X(1)=0,Y(1)=0], [X(2)=1, Y(2)=1] & [X(3)=2, Y(3)=0]

iv) EXCITEID of TLOAD1 used DAREA load type, with dof x (local coordinate system, perpendicular to the panel) set to 200 (200N)

v) NLGEOM(impl static) loadstep used. Inserted SPC,NLOAD (set to TLOAD1), NLPARM & TTERM=2.0

 

However, when I tried to run the analysis, ERROR #1388 popped up.

Referenced ID 9 (ID of TLOAD1) in NLOAD, but missing in BULK DATA.

 

When I change the load input to a displacement input, using NLOAD1 load collector with SPCD as EXCITEID, no error occurred during analysis computation.

 

Please help me in determining what's needed to be changed.

 

Shukri.

 

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Hi Shukri,

     

    Please refer NLOAD1 in NLOAD for NLGEOM analysis.

     

    TLOAD1 is for transient dynamic analysis.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Do I change the DAREA to SPCD too?

     

    When I used DAREA, I got a fatal ERROR #4079, Non-convergent nonlinear iterations for subcase 1.

    When I used SPCD, I got ERROR #4028, No load is defined in NLGEOM subcase 1.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    What is the EXCITED type are you using?

     

    If the excitation type is NOT enforced motion, then you need DAREA.

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited April 2015

    Adding my comment aswell.

    Use DAREA for Load (Force)

    Use SPCD for Displacement, Velocity and Acceleration

    Regards

    Rahul R

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    I used the DAREA, but somehow got the Non-convergent nonlinear iteration error.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Try increasing NINC in NLPARAM and check if the analysis is successful or not.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Increased from 10 to 20. Still not successful.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Hi,

     

    Please share the .out file.If you are a commercial customer, you can contact your local support @ http://www.altairhyp...ortProduct.aspx for a much faster support.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    I finally got it work after a few tweeks on the test setup.

    I reduced the gap between the ball indenter and the panel from 1mm to 0.5mm.

    And in the PCONTX setting, I increased the GAP function from 0.5 to 2.0mm.

     

    So far, the analysis managed to complete its calculation.

     

    Thanks for all the help and guidance.

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