[DEM Theory] Limit size of particle ?

[dxvn818]

Hi all,

I have read papers about the Discrete Element Method (DEM) and a little about Molecular Dynamics (MD). According to what I understand, the main difference between these two methods is the scale and interaction force model. MD works for micro-scale while DEM works for meso-scale. MD uses interaction force derived from potential function while DEM uses the short-range interaction model, such as dual-spring dash-pot or cohesive beam model.

However, I do not understand the limit size of particles in these methods. What I mean is: Although DEM is mainly applied for meso-scale problem, is it possible to apply DEM for domain with size of nano-meter or micro-meter ?

Thank you for reading and answering my question,
Vinh

[Damien André]

Hello Vinh,
MD and DEM are absolutely same approaches. Differences are mainly the interactions laws between particles.

-> MD uses van der Waals laws able to simulate interactions between molecules.
-> DEM uses rheological model able to simulation contacts between grains
-> GranOO uses beam model able to mimic cohesive media

Depending on your physical problem (scale, material...) you are free to choose between these approaches.
In GranOO, the resulting behaviors do not depend on the scale.

You can use the same model for nano-micro-meso-mega scales, it will not affect results. But, if you want to simulate something at nano-scale, colloidal interactions become non-negligible and MD models will be more suitable for your physical problem.

[dxvn818]

Hi Damien,

Thanks for your explanation.

Vinh