[EDEM] How to Query the Torque on a Mixer Blade in a DEM Mixing Simulation?

Question

Hello,

I am currently developing a mixer simulation that mixes three types of particles.

I would like to obtain the torque acting on the mixer blade, but I am not sure which options I should select in the Query settings.

My current understanding is:

* Geometry: Torque
* Section: blade(IMPPELER)
* Query Type: Total?
* Component: magnitude?

Would this be the correct setup to extract the torque on the blade?

Thank you.

Stephen Cole · Accepted Answer

Hi,

It looks In general you want Torque with query type 'total' and Component X, Y or Z rather than Magnitude.  If you choose X,Y,Z EDEM will give you the torque along this axis passing through the geometry centre of mass.

It like you are in 'selections' which is a way to choose a sub-section of a simulation, usually by area. You shouldn't need selections for torque on a specific geometry, i'd recommend either a line graph or export to .csv via File > Export > Results Data choose a query from there.

In the export data/graphing options you can choose X,Y,Z or a 'Specify Axis'.

If you specify axis it will give you the torque along the axis you specify, which is my preferred method as you then have more control over the exact axis you are querying the torque.

In the above i'm querying the torque along the Z axis of a geometry section.  Link to geometry means if the geometry is translating (e.g. if it's also moving in the X axis) the torque axis will move with the geometry centre of mass.

Regards

Stephen

Stephen Cole · Accepted Answer

Hi,

Just to note in the API we set and get the torque per element.  A particle is an element and for the geometry it is the individual triangular mesh element on which we are calculating the torque, not the geometry section as a whole.

If in the Analyst you query torque > Standard it gives you the values on the individual mesh elements, which is what is calculated by the contact models.  When you query torque>Total in the Analyst it gives you the torque on the whole geometry.  The sum of the torque on the individual elements does not equal the Total torque on the geometry center of mass as we have to take into account the distance of the element to the goemetry CoM.

In the API you can get and set the forces and torques.  For example:

contactResults.additionalTorque1 += myvalue;

this will add myvalue (a vector) to the existing torque value.  If you wanted to get the torque just query it like:

CSimple3DVector myvalue = contactResults.additionalTorque1;

THe contact models are chained, so if you have Hertz-Mindlin in the contact model chain (in the EDEM creator physics) and then a custom API after this, the torque you query would be the torque calculated in the Hertz Model.  Also if you had a rolling friciton model after your API any torque you modify would be passed down the chain.  This is why its best to use "+=" rather than "=" when adding a value to the torque to avoid overwriting the results.

You have different torque vaues, the above is additionalTorque1 which is the torque on element 1 of a contact pair, you typically will want to apply equal and opposite values in additionalTorque2

There is also usAdditionalTorque which is the component which causes energy loss.

From the docs:

There is a rolling friction API example which uses torque, it sets the torque but shows how to use it:

https://community.altair.com/discussion/36255/edem-api-contact-model-example-standard-rolling-friction-3-0