I am currently working on modeling nano-scale particles using EDEM.Thanks to the kind support from an Altair employee, I have confirmed that EDEM does not directly support meshing at the nano scale and some facts as below.
- The Fiber Bonding model requires sphero-cylinder particles that must be meshed, but EDEM cannot handle meshes at the nanometer scale, making this approach fundamentally impossible.
- Spherical particles in EDEM are not mesh-based, so individual nanoparticles can be created. Therefore, by using the Bonding V2 model, it should be possible to build a nano-scale “meta-particle” by bonding multiple spherical particles into a long chain.
- EDEM does not officially support Brownian motion or diffusion effects that arise at the nanoscale.
- In the current version of EDEM, contacts between particles smaller than 1 µm cannot be detected; contact detection down to 1 nm is planned for the 2025.1 release.
Based on the above understanding, my question is as follows:
First ,
I would be grateful if you could kindly confirm whether the above points are accurate.
Plus related with number 4 above,
When it’s stated that “contacts smaller than 1 µm cannot be detected,” does this mean that contact between a 4 nm spherical particle and a geometry would also go undetected?
In other words, would a 4 nm particle simply pass through the geometry without registering any collision?
Second,
I am now attempting to model DNA structures by connecting spherical particles— which do not require meshing—into meta-particle chains. In the process, I encountered an issue I would like to ask about.
While entering physical properties, I noticed that some values appeared in red text, as shown in the attached image.Could you please clarify the exact meaning of this red text?
- Does it indicate that the value is physically invalid or out of an acceptable range, and that EDEM will automatically adjust it to the nearest permissible value during simulation?
- Or is it simply a warning, suggesting that the entered value is unusually small or outside the typical range, and should be reviewed?
Third,
I have also learned that EDEM does not provide built-in models for Brownian motion or viscous damping in solution. Nevertheless, I understand that the EDEM API allows users to define custom forces. My intention is to apply a random force—sampled from a Gaussian distribution—to each nanoparticle at every time step (for example, by bonding ten spherical particles with the Bonding V2 model to create one meta-particle, then applying the random force separately to each of the ten constituent particles).
Could you advise whether implementing such a force via the API is feasible?
Any suggestions or insights would be greatly appreciated. Thank you in advance!
