Altair RISE

A program to recognize and reward our most engaged community members

Nominate Yourself Now!

Error when coupling EDEM with Motionview

Hello,

I'm trying to run a co-simulation with EDEM and Motionview. I have watched the elearning course. But when I hit run, the log reports error and simulation fails:

WARNING: Stepsize has diminished consistently below h_min [=1.000E-06].

ERROR: At time=4.628E-04 the integrator failed to proceed.

I'm not sure what the problem is.

Also, when I tried to figure out what's wrong, I can not seem to change anything in the the Assembly-EDEM dropdown box (One that has Communication interval etc.)

I would really appreciate the help.

Thanks,

Keyu

Find more posts tagged with

EDEM

MotionView/MotionSolve

Accepted answers

All comments

GTT Adam

Hi @KeyuWang_UWO,

That error is commonly presented when the simulation has encountered something so transient that the integrator fails. By either loading the animation in HyperView or EDEM you can usually visually see what went wrong at the time shown. Sometimes, you'll need to use HyperGraph to look at certain data channels to see if a signal was changing beyond what is physically possible, like growing exponentially to infinity.

Typically, you can try to separate the simulations as well, and just run the MotionView simulation first to make sure everything behaves as expected. If you find an error, correct it and then try the coupled simulation again.

Is this a tutorial model you are working on that you could share here?

Hope this helps!

Adam Reid

KeyuWang_UWO

Hello Adam,

Thank you for the reply. The simulation only ran for a very short time(0.002s), I can't tell anything from the animation, only the bulk particle volume suddenly expanded.

And I think my Motionview model works fine because I made sure it works before doing the co-simulation. But just to be sure again, could you please share how I can separate the simulation now? because when I stop the coupling server in EDEM and run Motinoview, the log says 'Failed to connect to EDEM' and just terminate the simulation.

Yes, I can share here.

Thank you,

Keyu

GTT Adam

Hi @KeyuWang_UWO,

By decoupling the simulation, I mean to make a copy of your MDL, delete the DEM system (to remove any EDEM interaction), and run the simulation from within MotionView. This way you can ensure that the system response negating the particles is correct. But it sounds like you had already complete that step.

Hope this helps!

Adam Reid

KeyuWang_UWO

It is a Chain and Sprocket model running in sand bed. The Chain and Sprocket model is moving forward and chain is driven by the large sprocket. The sand bed is 6m tall and created using material block, and I have ran 20s to let it stable with minimum speed: 2.6314e-05 m/s; maximum speed: 0.030929 m/s.

And at 0.002s the bed expand and simulation stops.

I wanted to share the model here but the EDEM files are too large(over 100MB). Are there other ways I can send it to you?

Thanks,

Keyu

GTT Adam

Hi @KeyuWang_UWO,

Does the material bed expand before contact is achieved? Similar to decoupling the MotionSolve simulation, you can also decouple the EDEM simulation and try simulating the material bed, without the chain and sprocket, and make sure that the material bed does not expand on its own.

Hope this helps!

Adam Reid

KeyuWang_UWO

Hello Adam,

I think the bed is stable.

I have made a smaller bed. Here is the model. Please take a look.

Thank you,

Keyu

Chain and Sprocket in sand.zip

KeyuWang_UWO

Hello Adam,

Here you go.

Thanks,

Keyu

Chain and Sprocket in sand.zip

KeyuWang_UWO

Hello Adam,

I think I found out part of the problem. It is in EDEM. In the coupling Elearning video, it say to export EDEM simulation time to 0s before co-simulation, so I followed that after I created a stable bed. But after I opened the time 0 case and ran a few more seconds to see how it goes, particle exploded. Then I tried export but don't set simulation time to 0s, and ran, case was steady.

Any idea why this happened? And do I have to export EDEM simulation time to 0s before co-simulation?

Attached is my bed, I ran 2s; and export to 0s, and ran exported for 2s more, explode; but if I export at 2s, and ran exported for 2s again, didn't explode.

MV-EDEM practice-sandbed.zip

This coupled simulation is a simplified model that is helpful to my research, so I would be really grateful if you can help me figure this out.

As for the relative size of objects, I have enlarged my geometry 10 times, we'll how it goes.

Thank you,

Keyu