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Re: [lammps-users] multi-scale simulation
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Re: [lammps-users] multi-scale simulation


From: Axel Kohlmeyer <akohlmey@...24...>
Date: Thu, 26 Apr 2018 05:49:26 -0400

On Thu, Apr 26, 2018 at 5:12 AM,  <xudong.wang@...7565...> wrote:
> Yeah, I see. However, because the sintering process is at low temperature
> (about 500K), only a very small interconnection part between the two
> microparticles will be sintered. The rest part, most part of particles,
> would be seen as stationary.

that is irrelevant for the considerations i mentioned. in fact, what
you say here, speaks even more in favor of simply looking at carefully
chosen all-atomic scale studies of parts of the process. in my opinion
again, you don't seem to be considering time scales and length scales
properly. e.g. at the diameter of your particles, you cannot visually
distinguish the surface of a spherical particle from a flat surface.
and what about surface roughness? are your particles single crystals
or rather multi-crystal compounds with lots of different lattice
orientations and resulting sub domains and domain boundaries?

from my observations, the primary case where i would see value in
using AtC would be to study mechanical properties of the final
compound. and even there, it would require a carefully selected
subsystem. everything you said and explained so far points toward
looking at a mesoscale model as the proper tool for what you want to
do.

> Furthurmore, I have another problem, I ran the AtC exemples of LAMMPS and
> .case file was producted. But I cannot open it with EnSight. Always ‘error
> reading datas’ appeared. So any help of this?

no. i don't use ensight. does it say anywhere, that those files are
supposed to be readable by it?

axel.

>
>
> Best regards
>
>
>
> De : Axel Kohlmeyer
> Envoyé le :2018年4月25日 18:38
>
>
> À : xudong.wang@...7565...
> Cc : lammps-users@lists.sourceforge.net
> Objet :Re: [lammps-users] multi-scale simulation
>
>
>
> On Tue, Apr 24, 2018 at 3:41 AM,  <xudong.wang@...7565...> wrote:
>
>>
>
>>
>
>> Thank you Axel
>
>>
>
>> My particles are about 3-4 micros and it exists some formulations to solve
>
>> the time scale problem. I have simulated the sintering of nano-particles.
>
>> What I want to do now is to find a bridge between nanoscale and
>> microscale,
>
>> it’s why I think about learning ATC package.
>
>
>
> ...and this is why i think that you have not thought this through. the
>
> "bridge" you are looking for would be a *input* for AtC coupling, not
>
> something that you would be able to determine with it.
>
>
>
> remember, that for the time scales you are confined to the time scale
>
> of atomic scale simulations, so any process happening on the
>
> macroscale will be stationary.
>
> on the atomic scale, your nano particle will be indistinguishable from
>
> a bulk system within the error margins of classical MD models.
>
>
>
> axel.
>
>
>
>>
>
>>
>
>>
>
>> xudong
>
>>
>
>>
>
>>
>
>> De : Axel Kohlmeyer
>
>> Envoyé le :2018年4月20日 17:54
>
>> À : xudong.wang@...7565...
>
>> Cc : lammps-users@lists.sourceforge.net
>
>> Objet :Re: [lammps-users] multi-scale simulation
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>> On Fri, Apr 20, 2018 at 4:56 AM, <xudong.wang@...7565...> wrote:
>
>>
>
>> Hello everyone
>
>>
>
>>
>
>>
>
>> I’m now studying on the simulation of the sinterering process of
>
>> microparticle silver. Because of the big size of particles, I need to use
>
>> the ATC package. I want to treat the interconnected part between particles
>
>> by using MD and the other part by using FE (as shown in the figure below).
>
>> Do you think that my problem can be solved with this package please ?
>
>>
>
>>
>
>>
>
>> that is impossible to say at this level of generality. how large are the
>
>> particles and what is the time scale of the process you are looking at?
>
>>
>
>> unless i miss my guess, i would expect, that those length and time scales
>
>> are too far apart to make the kind of model you propose practical. if you
>
>> want to make some experiment, you should look for something much simpler.
>
>>
>
>>
>
>>
>
>> you may also want to do some research of the published literature into
>
>> available mesoscale models. it looks to me, that what you need could be
>
>> something conceptually similar to either lattice-boltzmann or
>> peridynamics,
>
>> or perhaps there might be a suitable formulation for either of them, that
>
>> you could use.
>
>>
>
>>
>
>>
>
>> axel.
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>> Best regareds
>
>>
>
>> Xudong
>
>>
>
>>
>
>>
>
>>
>
>>
>> ------------------------------------------------------------------------------
>
>> Check out the vibrant tech community on one of the world's most
>
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>
>> _______________________________________________
>
>> lammps-users mailing list
>
>> lammps-users@lists.sourceforge.net
>
>> https://lists.sourceforge.net/lists/listinfo/lammps-users
>
>>
>
>>
>
>>
>
>>
>
>>
>
>> --
>
>>
>
>> Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
>
>> College of Science & Technology, Temple University, Philadelphia PA, USA
>
>> International Centre for Theoretical Physics, Trieste. Italy.
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>> --
>
>>
>
>> Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
>
>> College of Science & Technology, Temple University, Philadelphia PA, USA
>
>> International Centre for Theoretical Physics, Trieste. Italy.
>
>>
>
>>
>
>>
>
>>
>
>>
>> ------------------------------------------------------------------------------
>
>> Check out the vibrant tech community on one of the world's most
>
>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
>
>> _______________________________________________
>
>> lammps-users mailing list
>
>> lammps-users@lists.sourceforge.net
>
>> https://lists.sourceforge.net/lists/listinfo/lammps-users
>
>>
>
>
>
>
>
>
>
> --
>
> Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
>
> College of Science & Technology, Temple University, Philadelphia PA, USA
>
> International Centre for Theoretical Physics, Trieste. Italy.
>
>
>
>



-- 
Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.