Re: How to impose sliding boundary condition without friction between two 3D meshes?

[Konstantinos Poulios]

Dear Anne-Cecile,

Regarding this question, you must decide first if you are going to do a small or large deformation simulation. I think your solid model for the brain is small deformations, so the method you suggest is ok. The syntax should be like

md.add_penalized_contact_between_nonmatching_meshes_brick(mim, "uh", "ub", "penal_r", None, HEAD_BOUND, BRAIN_BOUND)

penal_r must be defined as scalar data to the model. Use a not too big value to begin with, 1e4 or 1e5. This might give you a bit less accurate contact, but once it works you can increase this value further, or even switch to the more accurate version:

add_integral_contact_between_nonmatching_meshes_brick

But let's take this later when you have one basic version running.

BR

Kostas

On Fri, Nov 19, 2021 at 7:15 PM Lesage,Anne Cecile J <AJLesage@mdanderson.org> wrote:

Hi all,

 

 

To set up that the brain is sliding without friction inside the head, I wrote the following python lines

 

fbb = meshb.outer_faces()  # Boundary of the brain

fbh = meshh.outer_faces()  # Boundary of the head

 

HEAD_BOUND = 1;

BRAIN_BOUND = 2;

 

# selection of faces for contact condition

meshh.set_region(HEAD_BOUND, fbh)

meshb.set_region(BRAIN_BOUND, fbb)

 

md.add_penalized_contact_between_nonmatching_meshes_brick(mim3h, uh, ub, datanamer, HEAD_BOUND, BRAIN_BOUND, 1, lambda1_n)

 

Is it a good option? How to choose the parameters datanamer and lambda1?

 

Thank you

Best Regards

Anne-Cecile

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