montion of intruder in granular packing

Hello Ram,

Generally speaking you can normally do a lot of things about granular packings with Yade. But me I do not know what is an "intruder" ?
Generally you can use with Yade elements in shape of spheres, boxes, and facets (=finite surfaces with zero thickness). Note that you can bound spheres or facets to simulate more complex shapes.

Hi,
Thanks for reply. Intruder is big sphere moving in packing of small spheres in box. Intruder can also be cylindrical or other shape. We can find forces etc on that big sphere (named: intruder) due to other spheres in simulation box.
If I import mesh (STL) into YADE then is it possible to define its density etc in YADE?
Thanks,
Ram

For your first sentences :
"Intruder is big sphere moving in packing of small spheres in box. Intruder can also be cylindrical or other shape. We can find forces etc on that big sphere (named: intruder) due to other spheres in simulation box."

This is completely possible to be performed with Yade.

But, for your last sentence, which mesh do you have in mind ? And density of what ? Do you want to reproduce a precise sample of small spheres ?
For STL files, I know you can at least use them (import them in Yade) to define surfaces composed by the facets I told you before.

Hi,
I mean I want to import mesh(STL) of spherical geometry and then apply material properties like density, angular momentum etc to it. And then move that imported mesh in granular media same like big sphere created under YADE. Is it possible in current version of YADE? Please note that we can make that mesh in autoCAD software and export in STL format which then can be imported in YADE.
Thanks,
Ram

> and then apply material properties like density, angular momentum etc to it. And then move that imported mesh in granular media same like big sphere created under YADE. Is it possible in current version of YADE? Please note that we can make that mesh in autoCAD software and export in STL format which then can be imported in YADE.
Yes, it is possible. The only possible problem could be that contacts
tracking when contacts move from one facet to an adjacent one is not
fully implemented. I mean, it will work, but you will have small
inconsistencies with forces re-initialized each time the contact reach a
new facet of the intruder. We are working on this currently.

Bruno

Imported geometry in yade has no mass, it is non-dynamic, as it is constructed of facets, which are "flat".

You can move an imported body, rotate it, measure forces, affecting on this body etc., but it can not move "itself" due to an interaction with other bodies.

If you need this feature, you have to created an "artificial" sphere, give it material properties and put on this sphere the resulting forces from the mesh. Then you measure obtained displacements and rotations of this sphere and approximate those motions to your mesh. I think it is possible.

Hi,
Many thanks. How to create "artificial sphere? Can we make other "artificial" shapes, for example, cylinder, half cylinder etc which are also dynamical?
Thanks for help...
Ram

Main dynamic body is the sphere. But I think Bruno has done something
with cylinders (better to ask him).
Other shapes can be complicated and "expensive" in calculation time.

A.

On Fri, Apr 1, 2011 at 2:22 PM, Ram Chand
<email address hidden> wrote:
> Question #151276 on Yade changed:
> https://answers.launchpad.net/yade/+question/151276
>
>    Status: Answered => Open
>
> Ram Chand is still having a problem:
> Hi,
> Many thanks. How to create "artificial sphere? Can we make other "artificial" shapes, for example, cylinder, half cylinder etc which are also dynamical?
> Thanks for help...
> Ram
>
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We have some sort of cylinders but they have spherical ends. You'd need
to implement contact detection on flat ends if you need them (with
current rounded cylinders as a good starting point).

B.

Hi,
I have high speed PC, calculation time is no problem. Thanks
Ram

> Hi,
> I have high speed PC, calculation time is no problem. Thanks
> Ram

When you will have 2*10^5 particles and more, it will be a __real__ problem.

Anton

Hi,
Can you tell me how create cylinder and then to pour particles in that cylinder? I am totally new to YADE. I am user of LIGGGHTS and LAMMPS.
Thanks,
Ram

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