add Neo-Hookean solid #559
Open
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
richardschu
commented
Aug 25, 2023
| scalar I_1 = trace(C); | ||
|
|
||
| tensor F_inv = invert(deformation_gradient); | ||
| tensor C_inv = invert(C); |
There was a problem hiding this comment.
use tensor C_inv = F_inv * transpose(F_inv);
richardschu
commented
Aug 25, 2023
|
|
||
| scalar one_over_J_times_Dd_J = trace(F_inv * gradient_increment); | ||
| tensor Dd_F_inv = -F_inv * (gradient_increment * F_inv); | ||
| tensor Dd_C_inv = Dd_F_inv * transpose(F_inv) + F_inv * transpose(Dd_F_inv); |
There was a problem hiding this comment.
use scalar Dd_I_1 = 2.0 * trace(transpose(gradient_increment) * deformation_gradient);
richardschu
commented
Aug 25, 2023
|
|
||
| scalar one_over_J_times_Dd_J = trace(F_inv * gradient_increment); | ||
| tensor Dd_F_inv = -F_inv * (gradient_increment * F_inv); | ||
| tensor Dd_C_inv = Dd_F_inv * transpose(F_inv) + F_inv * transpose(Dd_F_inv); |
There was a problem hiding this comment.
use tensor Dd_F_inv_times_transpose_F_inv = -F_inv * (gradient_increment * F_inv) * transpose(F_inv);
and then tensor Dd_C_inv = Dd_F_inv_times_transpose_F_inv + transpose(Dd_F_inv_times_transpose_F_inv);
richardschu
commented
Aug 27, 2023
| * and | ||
| * | ||
| * Psi_iso = shear_modulus / 2 * ( I_1_bar - 3 ) | ||
| * |
There was a problem hiding this comment.
this 3 should be trace(I)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
this adds a first version of the Neo-Hookean solid to the material library. It is quasi incompressible, meaning the Poisson ratio can be chosen closer to 0.5 compared to other displacement-based formulations and locking is reduced. I tested it in the structure/bar application, where the
QuasiStaticsolver performed rather well. In general we immediately see the increased integration effort and increased iteration counts (linear solver, depending on the problem also nonlinear solver) -- both of these aspects should be tackled in the future. For now, we focus on the functionality. Also, I added some tests, taking the nonlinear rod solution as reference.