lees edwards boundary conditions implementation

Saeed Naamnh

Hi All , 

 

Can I implement lees edwards boundary conditions using edem? 

it seems that the conveyor belt motion is not representative for moving the walls in case of shear test. 

 

 

Best 

Saeed

Prasad Avilala_20558

Hi Saeed,

The conveyor motion might not be the correct option to use for the shear test i guess instead why can't you choose translational motion?

Conveyor motion is meant to use for conveying of bulk material it is not a correct option for other motions.

However, if you feel that Lees Edwards boundary condition implementation in EDEM meets your requirement you can explore. EDEM has a strong API capability.  You can refer to below example cases to understand EDEM API implementation

 

1) Tutorials, How To, Troubleshooting - EDEM API Tutorial 1: Particle Replacement (altair.com)

2) Tutorials, How To, Troubleshooting - EDEM API Tutorial 2: Plug-in Contact Model (altair.com)

3) Script & Model Library - EDEM API: Particle Body Force - Field Data Coupling – Choice of Drag Models with Lift Force (altair.com)

 

 

Thanks,

Prasad A

Saeed Naamnh

Prasad Avilala_20558 said:

Hi Saeed,

The conveyor motion might not be the correct option to use for the shear test i guess instead why can't you choose translational motion?

Conveyor motion is meant to use for conveying of bulk material it is not a correct option for other motions.

However, if you feel that Lees Edwards boundary condition implementation in EDEM meets your requirement you can explore. EDEM has a strong API capability.  You can refer to below example cases to understand EDEM API implementation

 

1) Tutorials, How To, Troubleshooting - EDEM API Tutorial 1: Particle Replacement (altair.com)

2) Tutorials, How To, Troubleshooting - EDEM API Tutorial 2: Plug-in Contact Model (altair.com)

3) Script & Model Library - EDEM API: Particle Body Force - Field Data Coupling – Choice of Drag Models with Lift Force (altair.com)

 

 

Thanks,

Prasad A

Hi Prasad A

The problem in translational motion is not periodic, and the walls keep moving even beyond the domain. in this case the particles will escape form the box. 

if you check the video in the attached link. i am looking to implement the same motion for the walls. Is that possible in EDEM

https://www.youtube.com/watch?v=eqrwrifIiP8&ab_channel=NitinKhola

 

 

Best 

Saeed

Prasad Avilala_20558

Saeed Naamnh said:

Hi Prasad A

The problem in translational motion is not periodic, and the walls keep moving even beyond the domain. in this case the particles will escape form the box. 

if you check the video in the attached link. i am looking to implement the same motion for the walls. Is that possible in EDEM

https://www.youtube.com/watch?v=eqrwrifIiP8&ab_channel=NitinKhola

 

 

Best 

Saeed

Hi Saeed,

This is Simple in EDEM you can use periodic boundary conditions under the Environment section

To understand the periodic boundary condition attached setup file will help you.

 

Thanks,

Prasad A

 

Saeed Naamnh

Hi Prasad A

 

Very helpful tutorial. 

BUT, my in my simulation i used CAD to create a bumpy top plate an bottom plate as shown in the pic.

and i applied the periodic BC on the right and left side. when i selected the translational motion the plates keep moving out of the domain. 

What i need is  to set a periodic motion like the youtube video for the upper plate (v= 1m/s) and lower plate(v=-1m/s),

Does cylindrical BC achieve that ? 

 

i also share a video of my simulation with conevyor motion 

Prasad Avilala_20558

Saeed Naamnh said:

Hi Prasad A

 

Very helpful tutorial. 

BUT, my in my simulation i used CAD to create a bumpy top plate an bottom plate as shown in the pic.

and i applied the periodic BC on the right and left side. when i selected the translational motion the plates keep moving out of the domain. 

What i need is  to set a periodic motion like the youtube video for the upper plate (v= 1m/s) and lower plate(v=-1m/s),

Does cylindrical BC achieve that ? 

 

i also share a video of my simulation with conevyor motion 

Hi Saeed,

I don't understand why particles are moving without any geometric motion.

Shear test to be performed by moving the top plate over the bulk material then you can observer the material shear.

If I am correct ,you gave motion to the particle assuming geometry is fixed with this you cannot able to represent the true shear behaiour.

I would suggest you follow the simulation deck which i shared to represent shear behavior

 

Thanks,

Prasad A

Saeed Naamnh

Hi Prasad, 

 

Thanks a lot for your corporation and help.

I totally understand what the periodic boundary is.

But the problem i have in EDEM that i cannot set the upper wall and bottom wall to move periodically. what i need, when the walls go out of the domain from one side they will come back form the other side (the same behavior for particles). the same motion in the youtube video

i attach another video that demonstrates the problem. the simulation only for the walls moving in opposite direction and keep moving for infinity. 

 

  

 

Best 

Saeed

Prasad Avilala_20558

Saeed Naamnh said:

Hi Prasad, 

 

Thanks a lot for your corporation and help.

I totally understand what the periodic boundary is.

But the problem i have in EDEM that i cannot set the upper wall and bottom wall to move periodically. what i need, when the walls go out of the domain from one side they will come back form the other side (the same behavior for particles). the same motion in the youtube video

i attach another video that demonstrates the problem. the simulation only for the walls moving in opposite direction and keep moving for infinity. 

 

  

 

Best 

Saeed

Hi Saeed,

Please use translation motion for forward and backward based on the length of geometry travel.

This solves your problem.

i.e  for example if you want to move the top and bottom geometry for 100mm in 1 sec then please use the translation motion as suggested

1) time=0 to 1 sec use translation motion forward with an velocity=100mm/s

2) time=1 to 2 sec use same translation motion in opposite direction of step-1

 

Hope this gives you the shear behavior.

 

Thanks,

Prasad A

Prasad Avilala_20558

Prasad Avilala_20558 said:

Hi Saeed,

Please use translation motion for forward and backward based on the length of geometry travel.

This solves your problem.

i.e  for example if you want to move the top and bottom geometry for 100mm in 1 sec then please use the translation motion as suggested

1) time=0 to 1 sec use translation motion forward with an velocity=100mm/s

2) time=1 to 2 sec use same translation motion in opposite direction of step-1

 

Hope this gives you the shear behavior.

 

Thanks,

Prasad A

Hi Saeed,

 

In YouTube video which you shared the shear test done differently.

Please share your deck if you're still facing difficulty in understanding in setting up of the shear cell test.

 

Thanks,

Prasad A

Saeed Naamnh

Hi Prasad A,

 

Kindly find the attachment.

in the settings  you will notice that I removed the effect of gravity and friction because i want to check the effect of bumpy surface in absence of gravity and friction 

 

 

 

Best 

Saeed

Prasad Avilala_20558

Saeed Naamnh said:

Hi Prasad A,

 

Kindly find the attachment.

in the settings  you will notice that I removed the effect of gravity and friction because i want to check the effect of bumpy surface in absence of gravity and friction 

 

 

 

Best 

Saeed

Hi Saeed,

Please find the generic shear cell setup model attached here.

The attachment consists of example files along with a presentation explaining setup details.

 

Hope this clarifies all your queries.

 

Thanks,

Prasad A