Yade

Model plastic deformation with cohesive bonds

Asked by David Alber

Dear yade launchpad team,

Situation:
An electrode consists of active material (sphere shaped particles) and binding(polymers, slightly wet) material, which glues together the active material. I want to simulate the compaction of the electrode and measure the force on the wall as a function of wall displacement. More precisely: a loose packing is confined by six walls. Then the upper wall moves downwards with constant velocity (loading). After the force on the plate exceeds a defined maximum it moves upwards again (unloading).

Challenge:
As a YADE beginner, it is hard to find the right contact law for this purpose. In particular, I seek a contact law that accounts for, elasticity of the particles, some cohesion (from the polymers) and gliding of particles under pressure (movement of particles in the polymer matrix). The contact law I seek should allow for gliding (position rearrangements) to dissipate energy during the loading phase. This would mean that even though the cohesion doesnt break I would have a macroscopic plastic deformation of the sample after the wall is removed again.

Question:
Can someone experienced recommend a YADE contact law for the situation described?
The contact law should feature:
    a) cohesive bonds between particles, that hold when particles move tangentially.
    b) (viscous) damping - something that dissipates energy from shear/normal velocity during loading.
    c)enable positional rearrangement, s.t. the compacted structure is maintained when unloading.

Question information

Language:
English Edit question
Status:
Expired
For:
Yade Edit question
Assignee:
No assignee Edit question
Last query:
Last reply:
Revision history for this message
Launchpad Janitor (janitor) said : 		#1

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

Revision history for this message
Jan Stránský (honzik) said : 		#2

Hello,

the problem (combination of problems) you described seems to be quite advanced.
All the mentioned points (a,b,c) alone can be achieved with Yade, but the combination looks like a challenging task.

What is the background of this task (PhD/master thesis, university project, other research project, ...)?
How long is dedicated for it (few months, one year, several years)?
How acceptable is developing a new contact model(s) (time consuming with uncertain result)?

The amount of answers suggest there is no Yade user/developer covering all the required features :-(

cheers
Jan

Revision history for this message
David Alber (davidalber) said : 		#3

Dear Jan,

Thanks for getting back at this post.
The background of this task is a master thesis. It should be completed within a time frame of 6 months.
Considering the tight time frame I am bound to the tools available in YADE. Developing a new contact model is out of the scope.

Recent research made me aware of the Luding contact model [1] and its Yade implementation Law2_ScGeom_LudingPhys_Basic(). The capabilities of modeling the physical effects of contact elasticity, plastic deformations and contact adhesion with a piecewise linear extension of the linear dashpot model, seem to be promising for modeling the mechanical behavior of battery electrodes.

[1]: [S. Luding, “Introduction to discrete element methods: Basic of contact
force models and how to perform the micro-macro transition to con-
tinuum theory,” European Journal of Environmental and Civil Engineering,
vol. 12, no. 7-8, pp. 785–826, 2008]