# Using a gts surface as a shell and filling it using radius expansion method

Asked by Huihuang Xia on 2016-10-12

Hi,
I built an irregular gts surface in a CAD software, it looks like a sand or stone particle. I want to use dozens of sub-particle to fill this irregular shell using radius expansion method. After that, I plan to use many these irregular particle to conduct a compression test.
I wonder whether YADE can perform this task? If yes, can you give me a similar example for me to copy and study?
Many thanks and regards.
Huihuang xia

## Question information

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Solved by:
Klaus Thoeni
Solved:
2016-10-19
Last query:
2016-10-19
2016-10-18
 Christian Jakob (jakob-ifgt) said on 2016-10-12: #1

Hi,

Do you speak about clumps (rigid/non-deformable bodies consisting of several spherical particles) or about clusters (deformable bodies consisting of several spherical particles bonded together via cohesive contacts)?

Yade can handle both, but generation method may be different. Please also note, that Yade can also simulate polyhedral particles like shown here:
http://dx.doi.org/10.1016/j.powtec.2014.05.052

Regards,

Christian

 Huihuang Xia (huihuangxia) said on 2016-10-12: #2

Hi,
The polyhedral particle in YADE is crushable?? If yes, this polyhedral particle is a good choice for my simulation, can you give me an example?
Thanks,
xia

 Klaus Thoeni (klaus.thoeni) said on 2016-10-12: #3

Also, in regards of filling a GTS surface, have a look in examples/gts-horse [1], especially gts-random-pack.py.

HTH
Klaus

 Christian Jakob (jakob-ifgt) said on 2016-10-12: #4

I am not familiar with polyhedrons, but examples can be found here:

 Jan Stránský (honzik) said on 2016-10-17: #5

Polyhedrons are "crushable" in the sense that if a condition is met, it is
split in to 4 pieces, have a look at [1,2]. However, I think there is no
example yet..
cheers
Jan

2016-10-12 11:23 GMT+02:00 Christian Jakob <

> Question #402952 on Yade changed:
>
> Christian Jakob proposed the following answer:
> I am not familiar with polyhedrons, but examples can be found here:
>
>
> --
>
> _______________________________________________
> Post to : <email address hidden>
>

 Jan Stránský (honzik) said on 2016-10-17: #6

I added an example a while ago, see/try [1] to get some idea
cheers
Jan

2016-10-17 10:30 GMT+02:00 Jan Stránský <email address hidden>:

> Polyhedrons are "crushable" in the sense that if a condition is met, it is
> split in to 4 pieces, have a look at [1,2]. However, I think there is no
> example yet..
> cheers
> Jan
>
> wrapper.PolyhedraSplitter
> Polyhedra_splitter.cpp
>
>
> 2016-10-12 11:23 GMT+02:00 Christian Jakob <question402952@answers.
>
>> Question #402952 on Yade changed:
>>
>> Christian Jakob proposed the following answer:
>> I am not familiar with polyhedrons, but examples can be found here:
>>
>>
>> --
>>
>> _______________________________________________
>> Post to : <email address hidden>
>>
>
>

 Huihuang Xia (huihuangxia) said on 2016-10-17: #7

Dear Jan,

Thanks for you patience and kindness, I plan to fill a gts surface like a rugby using many sub-particles in YADE. I have saw your examples in github, but the polyhedron was created by some parameters rather than importing a gts or stl surface from a CAD package.
I wonder whether rugby like shape packed by sub-particles can be used as a new particle to perform another simulation in YADE??
Many thanks and regards.

Huihuang Xia

 Jan Stránský (honzik) said on 2016-10-18: #8

Hello,
the purpose of the new example was an illustration of crasching. For some
reference (also polyhdrons in Yade in general), see [4], [Elias2013] and
[Elias2014]
Polyhedra may be cunstructed either as random based on Voronoi tessalation
or you can directly prescribe positions of vertices (see utils.polyhedron
function [1,2]). So the CAD/STL import is possible, you have to make a step
between (extract vertices from the file and pass them to the polyhedron)
For the meaning of polyhedra_utils.polyhedra see [3].

I wonder whether rugby like shape packed by sub-particles can be used as a
> new particle to perform another simulation in YADE??

Here I don't know at all what you mean :-) please try to formulate the
question such that imagining yourself knowing nothing about the problem you
could understand the meaning..
- you can have one polyhedron, which may crush during simulation (and its
pieces can crush again and so on) like illustrated with the new example
- for some other approaches see (and try to answer) Christian's comment or
see [5]

cheers
Jan

2016-10-17 16:47 GMT+02:00 Huihuang Xia <

> Question #402952 on Yade changed:
>
>
> Huihuang Xia is still having a problem:
> Dear Jan,
>
> Thanks for you patience and kindness, I plan to fill a gts surface like a
> rugby using many sub-particles in YADE. I have saw your examples in github,
> but the polyhedron was created by some parameters rather than importing a
> gts or stl surface from a CAD package.
> I wonder whether rugby like shape packed by sub-particles can be used as
> a new particle to perform another simulation in YADE??
> Many thanks and regards.
>
> Huihuang Xia
>
> --
>
> _______________________________________________
> Post to : <email address hidden>
>

 Huihuang Xia (huihuangxia) said on 2016-10-19: #9

Hello Jan,

Thanks for your responses, you solved all of my problems and confusions.

Best regards,

Huihuang Xia

 Huihuang Xia (huihuangxia) said on 2016-10-19: #10

Thanks Klaus Thoeni, that solved my question.