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Contact problem in NLGEOM and NLSTAT cases

Hi,

I am using OptiStruct 14.0 to model 3D Four-point-bending test of L-shaped structure, two rigid loading cylinders and two rigid supporters have been created. I tried to use two different ways: 1) NLGEOM (geom non-linear impl static) 2) NLSTAT (non-linear quasi-static). However, the contact didn’t work well in these two cases, so please check the attached models and give me any suggestions.

Thank you in advance.

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Altair Forum User

Hi @Gregory1991

Can you try this attached model?

<?xml version="1.0" encoding="UTF-8"?>

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Altair Forum User

Hi, Mr. Prakash Pagadala,

I tried the model you attached. Fortunately, the results I got is similar with yours, However, the following information could be seen:

*** ERROR # 4079 ***
Non-convergent nonlinear iterations for subcase 1.

ANALYSIS COMPLETED.

*** SOME ERRORS WERE REPORTED DURING THE RUN,
*** PLEASE VERIFY RESULTS AS THEY MAY BE INVALID.

Do you know why does the error happen because I used your model?

Besides, about NLSTAT model I attached above, could you also please check it?

Altair Forum User

@Gregory1991

Try this model file

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Altair Forum User

Hi, Mr. Prakash Pagadala,

I tried the model you attached. It can be convergent now. However, considering the further optimization work, NLSTAT is better since NLGEOM is time-consuming and convergence difficulties.

About NLSTAT attached model, the contact between L-shaped structure and supporters cannot work well. Could you please check it?

Thank you in advance!

<?xml version="1.0" encoding="UTF-8"?>

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Altair Forum User

@Gregory1991

I am already working on it. I think the problem is with the cotact stiffness. Meanwhile please proceed with NLGEOM. I will update when I have some valid results.