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Re: [lammps-users] The whole system will rotate around Z axis
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Re: [lammps-users] The whole system will rotate around Z axis


From: Axel Kohlmeyer <akohlmey@...24...>
Date: Sun, 2 Jul 2017 06:28:24 -0400

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On Sun, Jul 2, 2017 at 2:43 AM, Asadollahzadeh
<niliasadollahzadeh@...24...> wrote:
> Hi my friends!
> I am using LAMMPS to simulate an  eam  system recently. I want to use
> velocity command for applying pure shear.My velocity value is (0.0006
> Angstroms/picosecond).I don't know which command is true...
> Command number 1 or 2 ???

why don't you try both and see which one gives you the result you
desire, if any?
that is easy enough to do and the "scientific way" to solve a problem.

axel.


>
> 1) velocity    middle  ramp  vx  0.0   0.0006  y  ${lim02}   ${lim03}  sum
> yes
> or
> 2) velocity    middle  ramp  vx 0.0006   0.0006  y ${lim02}   ${lim03}  sum
> no
>
> May anyone give some advice to make the system on the true way ?
> Thank you in advance.
>
> regards,
> Nili
>
>
> On Fri, Jun 30, 2017 at 4:07 PM, Axel Kohlmeyer <akohlmey@...24...> wrote:
>>
>> On Fri, Jun 30, 2017 at 7:32 AM, Asadollahzadeh
>> <niliasadollahzadeh@...24...> wrote:
>> > Thanks Pro.Axel,but I saw rotation in "vmd"??!!
>>
>> ...and i didn't.
>>
>> axel.
>>
>> >
>> > On Thu, Jun 29, 2017 at 6:04 PM, Axel Kohlmeyer <akohlmey@...24...>
>> > wrote:
>> >>
>> >> On Thu, Jun 29, 2017 at 9:02 AM, Asadollahzadeh
>> >> <niliasadollahzadeh@...24...> wrote:
>> >> > I am using LAMMPS to simulate an  eam  system recently. I have met a
>> >> > problem.
>> >> > When I used boundary as "s s p", the whole system will rotate.
>> >> > I had use the commands:
>> >> >
>> >> > echo                 both
>> >> > units                 metal
>> >> > atom_style       atomic
>> >> > boundary          s s p
>> >> > timestep           0.001
>> >> >
>> >> > region               simbox block -300 300 -300 300 -300 300   units
>> >> > box
>> >> > create_box      2 simbox
>> >> >
>> >> > lattice              fcc 4.0500
>> >> > region             cube block -30 30 -30 30 -30 30 units box
>> >> > create_atoms 1 region cube
>> >> > set                    group all type/fraction 2 1 12393
>> >> > mass         1 63.546
>> >> > mass 2 26.9815
>> >> >
>> >> > pair_style      eam/alloy
>> >> > pair_coeff * * AlCu.eam.alloy Cu Al
>> >> >
>> >> > #################### Equilibriation ####################
>> >> >
>> >> > min_style        cg
>> >> > minimize         1.0e-8 1.0e-8 1000 10000
>> >> >
>> >> > velocity all create 100 49284121 mom yes rot yes
>> >> >
>> >> > fix              0  all nvt temp 100 100 0.1
>> >> > thermo            1000
>> >> > thermo_style      custom step temp pe ke etotal
>> >> > dump              000   all     custom    1000
>> >> > dumpequilibration.lammpstrj id  type x  y  z
>> >> > reset_timestep    0
>> >> > run               100000
>> >> > unfix             0
>> >> >
>> >> >
>> >> >
>> >> > ##############################################################################
>> >> >
>> >> >
>> >> >
>> >> >
>> >> > May anyone give some advice to make the system not rotate?
>> >>
>> >> i just ran your input with the current version of LAMMPS, and there is
>> >> no visible rotation.
>> >> rotational velocities as computed via the omega() variable function
>> >> remain under +/-5.e-17, i.e. are within the range of numerical noise,
>> >> throughout the run in every direction.
>> >>
>> >> axel.
>> >>
>> >> > Thank you in advance.
>> >> >
>> >> > regards,
>> >> > Nili
>> >> >
>> >> >
>> >> >
>> >> > ------------------------------------------------------------------------------
>> >> > 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.
>
>
>
> ------------------------------------------------------------------------------
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>



-- 
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.