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.
Can I change the percentage of the contribution of the plastic strain in phase field damage?
Posted 12.07.2025, 05:22 GMT-4 Structural Mechanics, Material Models Version 6.2 2 Replies
Please login with a confirmed email address before reporting spam
Hi
I am trying to build a model to simulate the fracture of a ductile metal. I am trying to use the phase field damage models under solid mechanics interface. When I was checking the user's mannual, I found this description:
"By selecting Total strain energy density, additional contributions from dissipative material features, such as creep, plasticity, and viscoelasticity, are added. Select the Calculate energy dissipation checkbox in the parent material model to compute these variables."
For the problem I want to solve, I do need some plastic contribution in the driving force for the phase field interface evolution. However, usually only 10% of the plastic work is considered to be stored in the material and is available for creating new surfaces, the rest of it is considered dissipated through heat.
I am wondering if I select the* Total strain energy density*, and select the Calculate energy dissipation checkbox, the how much of the plastic contribution is taken into account by COMSOL? Is it all of it? If so, how could I regulate the model to have only 10% of the total plastic work to contribute in the phase field damage driving force?
best wishes Runzi
Please login with a confirmed email address before reporting spam
Hi Runzi,
As you describe, selecting Total strain energy density and enabling the Calculate energy dissipation checkbox will make COMSOL take the entire plastic energy dissipation into account when computing the crack driving force.
To get the behavior you describe with the dissipated plastic energy contributing partially to the phase field evolution, you can set the Crack driving force to User defined, and use an expression like (pfdmg1.Ws0+0.1*solid.Wp)*lint/Gc
in the Phase-Field Damage multiphysics coupling node. In the expression I have assumed that you have defined a parameter or variable for the internal length scale lint and the critical energy release rate Gc, and that you have Plasticity and Phase-Field Damage active on the same selections so that solid.Wp is properly defined when computing the crack driving force.
Cheers,
Adam
Please login with a confirmed email address before reporting spam
Hi Adam
It is a very useful suggestion. Thank you!
Best Runzi
