Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Finite Strain Formulation For Solid Mechanics Module
Posted 2022年7月28日 GMT-4 05:08 Structural Mechanics, Physics Interfaces, Material Models 0 Replies
Please login with a confirmed email address before reporting spam
The below post is related to an archived discussion
Hello everyone,
I have a query regarding External Strain sub-node for a hyperelastic material and I hoped someone could help me. I understand that when we add an External Strain for a hyperelastic material in solid mechanics module, COMSOL first calculates the elastic Second Piola- Kirchhoff Stress and then, using a pull-back operation determines the same stress in undeformed (material) configuration. I was wondering how the elastic Second Piola- Kirchhoff Stress is being calculated for a hyperelastic material?
As you can see in the attached screenshot which is the equation view section for a hyperelastic material, COMSOL is calculating the elastic Second Piola- Kirchhoff Stress first, by taking the derivative of the strain energy function (Ws) with respect to the elastic right Cauchy-Green tensor (Ce), until this part everything seems to be correct but after taking the derivative, the result is being divided by the Jacobian of the inelastic deformation tensor (Ji), I am curious what is the reason that the derivative is being divided by the Ji? because according to Hooke’s law, Ji is just being used for the pull-back operation and not in the definition of the elastic Second Piola- Kirchhoff Stress.
Thank you in advance for any feedback.
Attachments:
Hello Lucas Jones
Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.
If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.