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[hamednik]

Hello

I am analyzing a simple compression on a lattice structure. I have enabled the body interaction (trajectory) so the body does not penetrate into itself. However, in large deformation, it does not work and the body penetrates into itself as shown in the below image:

I cannot use the "proximity-based" either as the below error pops up with "proximity-based contact":

"The physical distance between bodies in the model falls within the selected tolerance for proximity-based contact.
Try using a smaller body interactions “Pinball Factor”, moving bodies to give sufficient separation
or switching contact detection to use trajectory contact."

 

I wonder if there is a way to avoid self penetration in this model.

Thanks

 

[Aniket]

Ansys staff can not download files, but are you looking at the results at a scale of 1?

-Aniket

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[hamednik]

Yes. It is true scale. But the question is not about the deformation, it is about the self-peneteration.

[Aniket]

• To avoid self penetration, you can switch Body Self Contact to Yes under Body Interactions with the Trajectory method. 


• If you are using the Proximity method, you can use the Pinball Factor. You can set it between 0.1 to 0.5, where 0.5 means 50% of the smallest element size. 


• You can also try reducing the time step size. If the time step is large it may fail to detect contact. 

 
For more details on various options on Body Interactions, you can visit following Ansys Help link:
https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v195/exd_ag/ds_body_interactions.html
 

-Aniket

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[hamednik]

Both Body self Contact and Element self contact is on. I have tried many different values for Pinball factor and timestep safety factor. But it doesn't work the body always penetrate into itself. 

The link you sent also doesn't work.

Hamed

[peteroznewman]

Hamed, the last line in Aniket's post give you instructions on how to use the help link. Please follow the link on the last line and read that.

[hamednik]

 I read this help but there is no further information. I have tried changing every parameter but it still doesn't work. I have defined contact as well as body interaction between all the surfaces and still, it doesn't stop the self-penetration.

[Kai]

Hamed, what does the undeformed geometry look like?  Can you try to define manual contact region in those self penetration area?