Pressure inside a body

[srosset]

Hello,

I am trying to model the deformation of a soft elastomeric cylinder, under the action of a compressive electrostatic force (i.e. electroactive polymer). To correctly model the situation, I should used couple physics, solve the electrostatic problem, compute the force, and then solve the structural problem.

However, in a first phase, I want to do purely structural analyses, and I use a constant pressure on the boundary, to model the electrostatic pressure.

My problem is the following: The line (I use a 2D axisymmetric model) on which I have to apply the electrostatic pressure is not on the outside of the geometry, because there will be another layer on top of the active part where the force is generated. (see attached image). However, when I apply a pressure on this line, ANSYS put a pressure on both side of the line, when I only want a downwards pressure that compresses the right A1 area.
When I dont have the A2 material on the top, it works perfectly, probably because the line on which the pressure is applied is at the outside of the model.
But when I add this second material A2 on the top, applying a pressure on the "burried" line causes the creation of two counterbalancing forces.

How can I solve this problem?

Thank you!

 

[cbrn]

Hi,
the behaviour you are facing is normal. It's a problem of... normals (!) associated to the line. When both layers are active, the line is common to two adjacent domains having opposite normals.
In order to have the correct result, you do have to unselect the outer region(s), then apply the boundary condition, the SBCTRAN (transfer BC from solid model to FE discretization), then reactivate the outer region(s).
Regards

 

[srosset]

Thank you for your reply, I will try it right away. I found a workaround by applying the pressure on the elements, but it is a little bit more work to select the correct elements.

It is actually a little bit dumb of me to have gone in the right direction by selecting just the elements that were needed, but not to have thought about doing the same with the areas!