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Hallo

Ich versuche, ein Kontakt Problem zwischen einem starren und einem verformbaren paar eines 3D-Modells zu analysieren. Die Maschenweite ist 0,03 für den verformbaren Teil und 0.0045 für starre. Die Ergebnisse die ich bekomme sind anders als experimentelle und Fehler von 17 %. Kann mir bitte jemand sagen, was das Problem ist?

Vielen Dank im voraus
Bruce

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Hi Bruce,

Your problem is not fully understandable. But what I understand is, that you have got a rigid and a soft part connected with contact (bonded? sliding? linear?). You created a much finer mesh on the rigid part. Correct?

For contacts the meshes on both parts should be either equal or finer on the "soft" (or "small" or "round" or "pointed") side. Please also make sure that the contact is on the soft side and the target on the rigid side. Do not use symmetric contact.

Hope this helps.

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Gruß, A.

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Hello,

Thank you for your reply . I wrote it wrong. The mesh size on target surface is 0.0045 and on contact is 0.003. I am using a standard contact. Yes the contact is the soft side and target is the rigid one. But still the result is deviating by 17%. I have done everything already except for asymmetric contact. Could you tell me why asymmetric contact has to be used?

Regards,
Bruce

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Hi Bruce,

Relation of mesh sizes on target and contact seems ok.
If you do not use assymetric contact, WB automatically creates another pair of contact with Target/contact swapped. As far as I know, WB then enables one pair, but it often does not decide correctly which side is the contact. That's why you should force Ansys into the correct definition.
Please explain which results you are interested and what kind of deviation is meant. If you are interested in contact pressure or penetration, you should have a careful look into contact definition:
- set initial contact stiffness to 0.1
- adjust contact stiffness "every iteration"
May be you have to activate NLGEOM,on (large deflections) depending on your boundary conditions and loads.

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Gruß, A.

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Input.txt

Hello,

I am interested in reaction forces. I am using Ansys APDL 14.5. I have already done all the necessary settings. Contact stiffness as 0.1, adjusted contact stiffness to every iteration along with NLGEOM as On. Still I am unable to get it closer to the experimental value. Please find attached the input code with the necessary settings.

Regards,
Bruce

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Did you try pure penalty?
I am not  sure if the materialdefinition (mu=0) is correct. But I am not familiar with hyperelastics. Try to adjust the material properties and contact stiffness to the test results and then judge if the parameters are still in a reasonable range.
Please also check if you have a separate set of real constants and material type for every part.
Otherwise Ia can't help you any more.

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Gruß, A.

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