Packing of Medium Density

Hello,

> I am new to yade.

welcome :-)

Can anyone help me ...

please be more specific and define more precisely:
- packing:
    - spheres? clumps? polyhedrons? ... ?
    - sizes? uniform size? particle size distribution? ... ?
    - regular? random?
    - periodic or not? within what shape? ... ?
    - ...
- medium density, medium packing:
    - medium of what? between pure makeCloud and randomDensePack?
- more rigorous definition and requirements:
    - E.g. only packing density, or also some spatial distribution requirements, ...

There are maaany options and the proper answer depends on what you actually want.

One solution is e.g. to use randomDensePack with larger particles then desired and than make the particles smaller to desired size.

Cheers
Jan

Thank you Jan for suggesting your solution.. I made changes in question.. Please check again and help.

Thank you
Amrisha

Hello,

thanks for adding more information, but still it is too ambiguous.
As I said, there are many approaches [2] with various requirements (on boundary, spatial distribution, size distribution, ...).

Please be more specific, clear and also please answer all the questions from my previous information request (and of course from this one).
Otherwise we can give just as general answers.

Also please read [1] and provide a MWE [1] for your loose and dense packing.

> Can anyone help me for finding solution to simulate medium packing of spheres?

How do you define "medium"?

What is "packing"?
- uniform size? particle size distribution?
- regular? random?

> help me ... to simulate medium packing
> My problem is to simulate loose, medium and dense packing of spheres

What does "to simulate" mean? Just to create? Or some actual simulation, like compaction?

> finding its packing fraction and porosity.

packingFraction = sum(4/3.*pi*pow(b.shape.radius,3) for b in O.bodies) / boxVolume

> Loose ... packing, I made

how?

> Which parameters need to be changed for solving it?

I doubt there is a parameter for such thing..
The packing creation is either loose (to spent as little time as possible) or dense (to make it as dense as possible).
For in-between case, probably you will have to develop your own approach (one "blind" option I gave in answer #1, randomDensePack and then reducing size of particles)

Cheers
Jan

[1] https://www.yade-dem.org/wiki/Howtoask
[2] https://yade-dem.org/doc/user.html#sphere-packings

Choose dense packaging first and go from there.

> packingFraction = sum(4/3.*pi*pow(b.shape.radius,3) for b in O.bodies) / boxVolume

with credit to Vasileios' answer at [3], it can be simplified to
packingFraction = getSpheresVolume() / boxVolume
using getSpheresVolume [4] (I did not know about the function).

Cheers
Jan

[3] https://answers.launchpad.net/yade/+question/704153
[4] https://yade-dem.org/doc/yade.utils.html#yade._utils.getSpheresVolume

Thank you for your response Jan and Bernard..
Following is the script for dense packing. I modify the gravity deposition tutorial. Suggest me the corrections if i am going wrong.
PROBLEM STATEMENT- Find packing fraction of dense packing of spheres which deposits under gravity in a rectangular box.

And please help me with medium packing of spheres.

from yade import pack

# create rectangular box from facets
O.bodies.append(geom.facetBox((.5, .5, .5), (.5, .5, .5), wallMask=31))
if 0:
# create empty sphere packing
# sphere packing is not equivalent to particles in simulation, it contains only the pure geometry
      sp = pack.SpherePack()
# generate randomly spheres with uniform radius distribution
      sp.makeCloud((0, 0, 0), (1, 1, 1), rMean=.05, rRelFuzz=.5, periodic=True)
# add the sphere pack to the simulation
      sp.toSimulation()
else:
# add dense packing
      O.bodies.append(pack.regularHexa(pack.inAlignedBox((0,0,0), (1,1,1)), radius=.05, gap=0))
O.engines = [
        ForceResetter(),
        InsertionSortCollider([Bo1_Sphere_Aabb(), Bo1_Facet_Aabb()]),
        InteractionLoop(
                # handle sphere+sphere and facet+sphere collisions
                [Ig2_Sphere_Sphere_ScGeom(), Ig2_Facet_Sphere_ScGeom()],
                [Ip2_FrictMat_FrictMat_FrictPhys()],
                [Law2_ScGeom_FrictPhys_CundallStrack()]
        ),
        NewtonIntegrator(gravity=(0, 0, -9.81), damping=0.4),
        # call the checkUnbalanced function (defined below) every 2 seconds
        PyRunner(command='checkUnbalanced()', realPeriod=2)
]
O.dt = .5 * PWaveTimeStep()
O.trackEnergy = True

def checkUnbalanced():
 if unbalancedForce() < .05:
  O.pause()
O.saveTmp()

Thank you Jan for #5..
I run this command. I am getting following error:

NameError Traceback (most recent call last)
/usr/bin/yade in <module>
----> 1 packingFraction = getSpheresVolume() / boxVolume()

NameError: name 'boxVolume' is not defined

> NameError: name 'boxVolume' is not defined

it was meant to be already pre-computed value, like
boxVolume = width * depth * height

> And please help me with medium packing of spheres.

read this thread, help has already been given several times:
"Choose dense packaging first and go from there."
"One solution is e.g. to use randomDensePack with larger particles then desired and than make the particles smaller to desired size."
"probably you will have to develop your own approach"

> Following is the script for dense packing. I modify the gravity deposition tutorial. Suggest me the corrections if i am going wrong.
> PROBLEM STATEMENT- Find packing fraction of dense packing of spheres which deposits under gravity in a rectangular box.

It depends on the specific problem definitions.
It can be perfectly OK, or it can be pretty wrong, really depending on the definitions.
Like, should the initial packing be already dense? or it should be loose packing and made dense by the gravity deposition (more natural case IMO)?
Should it be one particle size, or rather various particle sizes?
... ?

Cheers
Jan