yade-dev team mailing list archive

[Feng Chen <fchen3@xxxxxxxxx>]

Hi, Janek:

Nice to hear from you, thanks for providing and supporting YADE, again!:-)

Regarding your question, as far as I know packmol (
http://www.ime.unicamp.br/~martinez/packmol/home.shtml) can handle initial
packing of spheres (or even complicated sphere clusters) by maintaining the
minimum distance between the sphere centers using a BOX-QUACAN
optimization, thus if you make the minimum distance greater than
max(r_i)*2, you should have zero overlap between the spheres.

Let me know if it is similar to you are looking for.


On Thu, Apr 13, 2017 at 2:10 PM, Janek Kozicki <janek_listy@xxxxx> wrote:

> Hello everyone,
>
> I am going back to work on yade, and I have some interesting plans.
> This also entails one question :)
>
> Sorry for goofy subject, I hope it catches your attention.
>
> In super-short I will tell you my history: since I left Grenoble in
> 2009 I attended a full 5-year course in physics at University of
> Gdańsk and I defended in 2015 master thesis in quantum mechanics.
> I was quiet here on yade-dev, because apart from full-time studies
> I was also working as associate professor at Gdańsk University
> of Technology. In 2014 I defended my habilitation on civil
> engineering/numerical modelling. Next week I will obtain a professor
> position at GUT in civil engineering department. Since 2015 I needed
> nearly 2-years to complete my physics education by self studying and
> individual talks with other physics professors. This evolved into my
> plans to implement quantum mechanics into yade in an elegant and
> documented way. As currently it only works for me and is not
> documented.
>
> Currently I got involved in a funded research that treats shale gas
> extraction. So I am paid a little to implement rock fracking, and
> I decided that this is a good opportunity for me to get quickly up to
> speed with current yade development process & methods. Implementing
> rock fracking will make easier for me to work on quantum mechanics
> later, and easier for *you* to watch me.
>
> During years 2009-2017 all other people in my department were using
> some older version of yade. And they lost touch with latest yade
> releases. This was my fault, since due to my full-time 5-year studies
> of physics I did not have time to keep them updated about latest yade
> versions. I think that I stopped updating yade for them around year 2012.
> Most of the time they were calculating concrete, and despite my
> encouragement to contact this mailing list and commit their changes,
> they didn't want to do so. Perhaps I didn't push them hard enough.
>
> Currently I will update yade for them, since some of them will now
> also want to calculate rock fracking. This means that I need to merge
> some of their changes into latest yade trunk. But actually when
> looking closer at this I see that there is only one simple change,
> which perhaps is already implemented in yade, and we just don't know
> about it. So there would be no need to port it, just use the
> different name for this feature.
>
>
> Now, here comes the question:
>
> To calculate concrete the sample made of spheres has some of these
> spheres overlapping. Since it is difficult to generate a sample where
> none of the spheres overlap. And with some overlapping the spheres
> want to "explode" until there is no overlap, sometimes cohesion prevents
> this, but we start calculations with non-zero forces between spheres.
> To mitigate this problem, the initial overlap between spheres is
> stored (on first iteration) and is treated as "zero" penetration
> depth during tension & compression.
>
> So the question is whether this feature is already implemented in
> yade under some name that you can give me, or whether I need to port
> this to yade.
>
> best regards
> --
> Janek Kozicki                               http://janek.kozicki.pl/  |
>
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