Error simulating displacement

[Luisa María Gavier Moreno]

Hi,

I'm trying to apply displacement conditions to a simple solid model. Specifically, I am applying displacement in X and Y directions through setting the values in that faces by Dirichlet conditions and in whose opposite faces I restrict the movement imposing values 0.0 using Dirichlet conditions as well. I attach a picture of the input file showing this information and another picture showing the employed values.

Input_file_conditions.png (28.59 KiB) Viewed 699 times

Displacement_value_file.png (1.09 KiB) Viewed 699 times

As a result, I have obtained what is shown in the last picture: one of the faces has done the displacement, but the other one (Y direction) just has tried to move the surface of the face.

Displacement_result.png (75.08 KiB) Viewed 699 times

Result with the initial model.png (59.61 KiB) Viewed 699 times

What I'm doing wrong? How can I impose displamecement conditions?

[Vijay Vedula]

Can you post the case files on Drive or Dropbox? It is better to take a closer look at these before suggesting anything.

-- Vijay

[Luisa María Gavier Moreno]

Of course, I attach the link to the files in Drive: https://drive.google.com/drive/folders/ ... drive_link

Thanks!

[Vijay Vedula]

I think there is a mismatch between the face names and intended boundary condition. For e.g., cara_lateral_1.vtp has a normal along y-direction and you named it as Y0, but cara_lateral_1sym.vtp has normal along x-direction, although you are assuming it to be along y-direction and applying displacement along y-direction. The same is true for the X1s plane that has inconsistent normal and therefore, the boundary condition is not correctly applied.

Also, is this problem described anywhere? Your choice of material parameters seem to make the material very stiff (highly incompressible material) and you are using struct to solve it that has a tendency to lock. Mesh is very fine too. If this problem is meant for testing the code, perhaps, you should try testing on a simpler problem?

-- Vijay

[Luisa María Gavier Moreno]

Yes, I'm sorry, there was a mismatch between the faces names and the boundary conditions. I have fixed it and now is correctly attached on Drive (https://drive.google.com/drive/folders/ ... drive_link). I run the problem again and the result can be seen below in the attached image, where you can see that there is a displacement of the two faces where I imposed the conditions, but the solid does not displace correctly.

In response to the material parameters, I'm using the same ones that have been used in one of the examples of svFSI-Tests, specifically the following : svFSI-Tests/05-struct/01-block-compression (https://github.com/SimVascular/svFSI-Te ... ompression). In that problem, compression is being applied on the patch and as a result, the generated displacement can be seen. In my case, I want to apply displacement and see the generated stress. I should change the material parameters and the equation type (maybe ustruct?) for the displacement problem?

On the other hand, in response to the mesh, I have also tested my problem with the same mesh that is used in the example: svFSI-Tests/05-struct/01-block-compression, keeping the same material parameters, but I did not obtain any good result.

Could you give some recommendations about the material parameters and equation type I should use?

Thank you for your help.

Luisa.