Units in EDEM and MotionSolve for Results in HyperView

FrankTUD

Hello, I am currently testing the co-simulation of MotionSolve, Twin Activate and EDEM using the example of an excavator (with version 2024.1):

https://community.altair.com/discussion/35588/excavator-dynamic-response-and-load-estimation-for-fatigue-analysis-in-motionsolve-twin-activate-and-edem

Unfortunately, I am having problems visualizing the results in HyperView. The program does not have its own system of units, but uses the sizes of the individual models. The MKS model was created in (mm), but EDEM only exports the results in the SI system (m). Even if the unit is changed to (mm), as described in the instructions, the results in HyperView are loaded in (m).

The approach of converting the MKS to (m) fails, as the program does not convert the sizes, but simply replaces them, i.e. 1m = 1mm, so that the entire model with the distances is no longer correct. These could be changed manually using the data summary, but the CAD data and the control are no longer correct.

Is there a simple solution that I do not yet know, i.e. either exporting the EDEM results in (mm) or scaling the model by a factor in MotionView. Based on the images in the instructions, it should work somehow.

In the CSV export for Hypermesh, you can choose between SI base units and EDEM special units, but then I only have the forces, but not the animation of the particles. Would be similar for the whole simulation.

GTT Adam

Hi @FrankTUD,

Typically you will need to update the Solver units, not Displayed units, to match in all interfaces to have a unified post-processing experience.

In MotionView, this can be done by editing the Solver Units Data Set (DS_Units) from MILLIMETER to METER.

Hope this helps!

Adam Reid

FrankTUD

@GTT Adam yes, but when i edit Solver Units Data Set (DS_Units) from MILLIMETER to METER in MotionView than the model crashed, because editing set 1 MILLIMETER to 1 METER and not 1 MILLIMETER to 0,001 METER

Greetings Frank

GTT Adam

Hi @FrankTUD,

Correct, a unit system needs to be set before defining the in MotionView model if you want it to align nicely with cosimulation between Twin Activate and EDEM. Since this is an tutorial model, it was designed using the MMKS system.

The curves can always be scaled in HyperGraph if you want to create plots in the MKS units system for this current model, and the next one you design you can make sure to change the solver units accordingly.

Hope this helps!

Adam Reid

FrankTUD

all right, but in the instructions and the results of @John_Dagg_0 example, both models are at the same scale, i.e. one has been scaled, the only question is how. either the mks model has been completely rebuilt or it is somehow possible to export from edem in the unit MM.

GTT Adam

Hi @FrankTUD,

In that tutorial, it mentions that the EDEM units should be changed in step 3 of the Model Setup and Simulation Steps:

Was that step completed?

Hope this helps!

Adam Reid

FrankTUD

Hi @GTT Adam, however, this is wrong in the instructions or does not help, as these are only the display units (see post above). in some faq from edem it also says that the export only takes place in SI units (i.e. in M).