yade-dev team mailing list archive

[Luc Scholtes <lscholtes63@xxxxxxxxx>]

Hi Janek,

Welcome back.

Very briefly:

We actually recently tackled "rock fracking" problems with Timos, Frederic
and Bruno (just have a look at:
http://www.sciencedirect.com/science/article/pii/S136516091730076X) by
combining the JCFPM and the PFV scheme.

Timos is still working on it but all the developments should be available
in current YADE version. Timos should also provide a simple working script
very soon (Timos, if you see this, please do it asap).

For your problem of non initially stress free packing, I am not sure I
understand correctly but you could have a look at the JCFPM where the
equilibrium distance is initialized at the contact detection. Besides, the
JCFPM enables to model materials with pre-existing discontinuities (e.g.
fractured rock masses) as described in several papers (see for instance:
http://www.sciencedirect.com/science/article/pii/S1365160912000391 and
https://academic.oup.com/gji/article/191/2/467/640987/Strength-characterization-of-rock-masses-using-a
).

Please do not hesitate if you want more details or explanations.

Cheers

Luc

2017-04-14 9:53 GMT+02:00 Bruno Chareyre <bruno.chareyre@xxxxxxxxxxxxxxx>:

> Hi Janek,
> In super-super short, welcome back!! :)
> More later.
> Bruno
>
>
> On 04/13/2017 09:10 PM, Janek Kozicki 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
>>
>
>
>
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