The meaning of alphaKr and alphaKtw in CohFrictMat
Hello:
I'm using CohFrictMat to define the material of the rock issue. And I have some questions in the coefficients of alphaKr and alphaKtw. In the tutorial guide, it says alphaKr and alphaKtw are dimensionless rolling(bending) stiffness and twisting stiffness, respectively. I wonder what does than mean and I have no idea how much the values are proper for granite as there seems no reference.
I will appreciate any kind of help.
Thanks!
Question information
- Language:
- English Edit question
- Status:
- Solved
- For:
- Yade Edit question
- Assignee:
- No assignee Edit question
- Solved by:
- Robert Caulk
- Solved:
- 2020-09-03
- Last query:
- 2020-09-03
- Last reply:
- 2020-09-03
|
#1 |
> it says alphaKr and alphaKtw are dimensionless rolling(bending) stiffness and twisting stiffness, respectively.
Imagine a beam connecting your two particles. If both particles roll along their shared axis, we install a spring that will resist this motion. alphaKr is the stiffness of that spring. Similarly, if the two particles twist along their shared axis, we install a spring that will resist this motion. alphaKtw is the stiffness of that spring.
> I have no idea how much the values are proper for granite
Unless you can find a paper that has calibrated these parameters for a similar material and similar scale (super important) that you are after - they don't directly correspond to any macroscopic conintuum mechanics parameters. Thus, these are calibrative. Like most DEM microparameters :-).
You are welcome to look at the source code to see exact implementation, if it will help you understand [1].
Cheers,
Robert
[1]https:/
Chen Lifan (chenlifan) said : | #2 |
Thanks Robert Caulk, that solved my question.