Problem with Large displacements simulation
Hello!!
I am triying to simulate a wing model with the large displacements card activated.
The model worked well with the loadstep type "Generic".
To make this simulation, first I switched to "Non-linear Quasi-static" analysis type.
Then I created a NLPARM load collector and added it to the loadstep in NLPARM(LGDISP) option.
The problem is that when I start the simulation, the Nonl_EUI_st, Err_EPI_st and Meas_EWI_st values does not change so the simulation does not converge and I get the error #4965 --> Maximum number of time increment cutbacks reached.
I even made a simplier model and the simulation went well!! So I dont know what is the problem with this file.
Thank you for your help!!
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Hi Adriano, thank you for your reply.
I was just taking a look at your post on Quasi-static simulations, and was interested in that option.
The problem is when I look the _nl.h3d to see what is going on I dont see anything, I think it may be because the model doesnt even make one succesfull iteration.
Hi Adriano, thank you for your reply.
I was just taking a look at your post on Quasi-static simulations, and was interested in that option.
The problem is when I look the _nl.h3d to see what is going on I dont see anything, I think it may be because the model doesnt even make one succesfull iteration.
do you have contacts? Do you have penetration in your contacts? Can you explain what do you have in your model?
Can you check what do you have in node 13540? (Max residual Force is ultra high)
What about node 5133? Residual moment is very high.
ITERATION 0
Nonlinear iteration summary for Subcase 1
Starting load increment 1 Current increment 1.0000E-001
Subcase 1 Load step: 1.0000E-01
--------------------------------------------------------------------------------
Nonlinear Error Measures Gap and Contact Element Status Maximum
Iter Avg. U EUI EPI EWI Open Closed Stick Slip Frozen Plststrn
--------------------------------------------------------------------------------
MAX FORCE 0.0000000000D+00 AT NODE 1 DOF 1
MAX RESIDUAL FORCE -.2941849633D+09 AT NODE 13540 DOF 2
MAX DISPLACEMENT INCREMENT -.2732928983D+00 AT NODE 7815 DOF 3
MAX DISPLACEMENT CORRECTION -.2732928983D+00 AT NODE 7815 DOF 3
MAX RESIDUAL MOMENT -.2702792081D+07 AT NODE 5133 DOF 4
MAX ROTATION INCREMENT -.6066682505D+01 AT NODE 7808 DOF 5
MAX ROTATION CORRECTION 0.6470581143D+01 AT NODE 7808 DOF 5
ELEMENT DISTORTION 15808
1 1.51E-04 1.00E+00 5.25E+01 5.25E+01 0 0 0 0 0 0.00E+00
There are no contacts in the model.
It is a simulation of half a wing under aerodynamic loads mainly. There are other linearly distributed forces tho.
There was a bad element in that node, I am repeating the proccess to see which nodes continue to fail!!
Thank you, hopefully that will be it, but if there is anymore trouble I will write you again!!
Hi, I did the proccess again and the residual forces went down, when I check the max nodes, there are no rare elements.
I think this was not the final problem.
I will attach you some images of the model and the new .out
can you share the .out file? It could give us some more insights about your model.
Also for N problems, i would suggest to request PARAM,NLMON,DISP for a better visual understanding of what is going on.
Also take a look at this blog post that gives you a brief explanation and tips on NL models.
https://community.altair.com/community?id=community_blog&sys_id=538764ab1b3790d4a5f742eddc4bcba4