Chip self contact in 2D orthogonal cutting

[VaggelisKas]

Hello community,

I have the following simulation problem.
I an trying to simulate a case of 2D orthogonal cutting.
The chip is normally created but when it curls up there is no interaction between the surfaces.

I have tried to use the self contact on the outermost surface of the workpiece but I get the error of the extreme deformation of
the elements.
Any ideas would be highly appreciated.


Thanks in advance.

 

[StefCon]

Hi,
Have you created a element surface set of the internal element faces and added it to the general contact? If not, maybe it could help.

 

[VaggelisKas]

Hello and thank you for your answer.
The general contact algorithm does not work at all for a 2D simulation.
The contact algorithm I use for this problem is a surface-to-surface contact with the master surface defined as the faces of the tool
that come in contact with the workpiece and a slave node based surface defined as the chip.
Any more help would be highly appreciated.

 

[VaggelisKas]

I still have not come up with any solutions.
Anyone has any ideas about how I can model it correctly?

 

[StefCon]

If you share the input file or .cae, maybe I or someone else can have a look.

 

[VaggelisKas]

Thank you for your answer.
What I am trying to do is as follows:
In order to simulate a correct 2D orthogonal cutting process I need to create a contact between these surfaces :

and this:

which are on the same body.
I have implemented a self contact algorithm about the first surface, but then, when the chip is curled, two more surfaces need to be have a contact property:
this one

comes into contact with this

The only contact I have used is a surface to surface contact that is as follows:

The result I get is:

My goal is to stop the elements on the tip of the chip to penetrate one another.
Can you tell me a correct way to implement these contacts?
I attach the .cae file.
If you need any more clarifications please let me know.
Thanks in advance.

 

[StefCon]

Hi,
By adding "self contact" to the top face and the face closest to the cutting tool, the contact you wish can be obtained.

I did have to change the mesh in order to get it working (not a nice mesh). It still looks a bit funny. I guess shear causes a strip of the cutting-curl to split. I think you are on the right track!

How confident are you in the material parameters?

Cheers!

 

[VaggelisKas]

Thank you very much for your effort!
I had that strip of metal on my model as well...in order to fix it there needs to be a more dense mesh below the chip area.
My material parameters are taken from a material library.
What kind of elements and meshing technique did you use?

 

[StefCon]

Hi,
No particular mesh technique. I basically made the mesh finer at the area where the tool first make contact with the work piece.
I used the same elements as you. The element library for this model felt a bit limited.
You might want to make the mesh quite a lot denser. Elements close to the cutting tool tip were stretched quite a lot before failing.

All details is in the previously attached input file. Note that the mesh was not nice (limited resources).

Too bad general contact don't work for 2D. I have done similar test models in 3D and it was a lot easier if I remember correctly.

Best regards,

 

[VaggelisKas]

The self contact of the faces you mention does the trick for the given step time.
But if I change the velocity BC and give a higher value and the curl goes further this happens:

That is proof that the simulation still needs something.
If you or somebody else has any more ideas as to how I can define the contact between these surfaces in 2D I would be very grateful.

Once again, thank you very much for your effort and advice.

 

[Mustaine3]

Maybe it it easier to extrude it to one row of 3D elements and use general contact.

 

[IceBreakerSours]

Have you tried playing with the contact stiffness scale factor?

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[VaggelisKas]

Hello community,

I tried a new approach to the problem.
In this model, my workpiece is a combination of 2 parts (workpiece-chip) bound together by a tie constraint.
Moreover, a new wire based part is created and placed on top of the chip via a tie constraint.
Below you can see the assembly without the chip part.

The interactions I have now are as follows:
a surface-to-surface int for the tool-chip
a surface-to-surface int for the tool-wire
a surface-to-surface int for the chip-wire
The simulation runs, but for a very big value of the clearance in the final interaction window.
If someone has any idea I upload the .inp file file for references.

Any kind of help would be highly appreciated.