EDEM-Hyperstudy connector with Type C rolling model

Hello folks,

I have been using both EDEM, Hyperstudy and the connector to perform my EDEM simulation calibration (kudos to the connection of the two! It has been very helpful).
Recently I have shifted from the standard model to using the type C model of rolling friction (Due to the kinetic energy issue in the standard model) which may then require further tuning of the rolling resistance and dampening coefficient, which are variable in the EDEM implementation. But I don't see those parameters listed in either the connector itself or the guidance.
Does anyone know how to add parameters not listed in the connector or will it require manual editing of the simulations?

Thanks!

Connector information: https://community.altair.com/csm/en/edem-hyperstudy-connector-installers-and-user-guide?id=kb_article_view&sysparm_article=KB0122022&sys_kb_id=a4d5be63976cfd10e3b0361e6253afe7&spa=1

Associated relevant links for anyone interested:
EDEM elearning, contact model: https://learn.altair.com/course/view.php?id=148
Hyperstudy connector: https://community.altair.com/csm/en/edem-hyperstudy-connector-installers-and-user-guide?id=kb_article_view&sysparm_article=KB0122022&sys_kb_id=a4d5be63976cfd10e3b0361e6253afe7&spa=1
Calibration blog: https://community.altair.com/community?id=community_blog&sys_id=ccdb8aa8db356910cfd5f6a4e296190a&view_source=searchResult
Calibration kits: https://community.altair.com/community/en/edem-calibration-kits?id=kb_article&sysparm_article=KB0121756&sys_kb_id=b7aea0c697247110e3b0361e6253af4d&spa=1

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Stephen Cole

Hi James,

Just to confirm it's these parameters you want to vary:

The type C model does use the Coefficient of Rolling Friction as the main input which can be modified by the Hyperstudy connector. I'll check with the developer on the above options.

You could use an API version of the TypeC model that reads the inputs from a .txt file and then parameterise the text file. For example https://community.altair.com/community/en/guide-on-how-to-parameterise-altair-edem-api-preference-files-with-altair?id=kb_article_view&sysparm_article=KB0122266

However I it looks like we don't have an API version of the type C uploaded to community, I've attached an older version of the code to this post but it's not CUDA GPU compatible. I'll make a note to update and upload a CUDA API version of the code.

Regards

Stephen

C_Type.zip

Fghfhn

Hey Stephen,

Thank you kindly for your reply.
They are indeed the parameters I am investigating if they need adjustment.

Rolling friction coefficient is the key parameter and no problem with that but I am concerned if the stiffness and dampening need further calibration. Also as you have there, using undampened force. Which seems it would then ignore the dampening term? An advantage of type c I understood to be that it further dampens the interaction.

There is unfortunately seemingly little available information about this and other software I have experience with seems to implement the stiffness and dampening a little differently where they aren't adjusted or are a function of other parameters (Rocky DEM and Aspherix/LIGGGHTS).
Definitely worried about having too many parameters to tune...

I think for now I will continue to try to see how they affect an angle of repose response, ideally how they affect particle-geometry force too.
I will stick with the GUI EDEM as the time saved on simulating the CUDA GPU is very useful and manually edit the values as specified for a DoE study. But thank you for sharing about the API option.

Kind regard,

James Hurrell

Stephen Cole

Hey Stephen,

Thank you kindly for your reply.
They are indeed the parameters I am investigating if they need adjustment.

Rolling friction coefficient is the key parameter and no problem with that but I am concerned if the stiffness and dampening need further calibration. Also as you have there, using undampened force. Which seems it would then ignore the dampening term? An advantage of type c I understood to be that it further dampens the interaction.

There is unfortunately seemingly little available information about this and other software I have experience with seems to implement the stiffness and dampening a little differently where they aren't adjusted or are a function of other parameters (Rocky DEM and Aspherix/LIGGGHTS).
Definitely worried about having too many parameters to tune...

I think for now I will continue to try to see how they affect an angle of repose response, ideally how they affect particle-geometry force too.
I will stick with the GUI EDEM as the time saved on simulating the CUDA GPU is very useful and manually edit the values as specified for a DoE study. But thank you for sharing about the API option.

Kind regard,

James Hurrell

Hi James,

The undamped force is the true force experienced by the particle in the contact, there is a bit more of a discussion on that here:

https://community.altair.com/community?id=community_question&sys_id=7c2a4e31db4d91d0cfd5f6a4e2961990&anchor=answer_1227367ddb49d1d0cfd5f6a4e2961960&view_source=searchResult

However it's not referenced in the literature for the rolling model which is why we added in the option to choose either, but for most models using a 'force' it is typically the undamped force to use.

Either way the rolling model removes rotational energy from the system (due to friction).

The type C model was implemented from this paper:

Ai, Jun & Chen, Jian-Fei & Rotter, J. & Ooi, J.. (2011). Assessment of rolling resistance models in discrete element simulations. Powder Technology. 206. 269-282. 10.1016/j.powtec.2010.09.030.

Where there is a bit more information on the coefficient of rolling stiffness and viscous damping ratio which if you were looking at varying inputs (other than the primary rolling friction value) are the two I'd investigate further.,

Regards

Stephen