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Re: [lammps-users] problem in fix indent
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Re: [lammps-users] problem in fix indent


From: Axel Kohlmeyer <akohlmey@...24...>
Date: Sat, 14 Apr 2018 11:03:35 -0400

On Sat, Apr 14, 2018 at 10:35 AM, Vijay Reddy <vijay00vegeta@...24...> wrote:
> Thank you for your response.
>
> I actually tried to simulate a thin slab diverting above the sphere (like an
> obstacle for the movement). That's why I want the indenter to remain fixed.
>
>  I understand now that fix move is a wrong choice for the movement of the
> slab.
>
> Can you please suggest any command for simulation such process (i.e.
> obstacles to the movement).

as i already explained, the difference is merely in the frame of reference.

axel.

>
> Thank you in advance.
>
>
> On Sat, Apr 14, 2018 at 7:43 PM, Axel Kohlmeyer <akohlmey@...24...> wrote:
>>
>> On Sat, Apr 14, 2018 at 9:58 AM, Vijay Reddy <vijay00vegeta@...24...>
>> wrote:
>> > Dear all,
>> >
>> > I have tried to simulate the indentation of metallic Ni alloy using fix
>> > indent. However, I want to keep the indenter at a fixed position and
>> > move
>> > the specimen toward the indenter using move linear command. But in this
>> > case, the indentation doesn't occur.
>> >
>> > If the process is reversed, i.e. the specimen is fixed and the indenter
>> > is
>> > linearly moved, there is absolutely no problem. Indentation occurs.
>> >
>> > I need to fix the indenter and move the specimen. Can someone help me
>> > with
>> > some suggestions.
>>
>> why? this is just a change of the frame of reference. just stick with
>> moving the indenter.
>> using fix move makes no sense, as it ignores forces and moves
>> particles according to the prescribed path.
>>
>> > The relevant section of the code is given below:
>> >
>> > # indenter position and radius at onset of loading
>> >
>> > fix         4 mobile indent 1000.0 sphere 60 60 122 25 units box
>> >
>> > fix 5 mobile move linear 0 0 5 units box
>> >
>> > thermo       500
>> >
>> > thermo_style    custom step temp c_new v_z v_disp1 f_4[1] f_4[2] f_4[3]
>> >
>> > dump         1 all atom 10
>> > AlNiCo_interface_dump.indent8_3d_unload.dump*.lammpstrj
>> >
>> > run 50000
>> >
>> > After running this code, a warning message shows:
>> >
>> > One or more atoms are time integrated more than once (../modify.cpp:266)
>>
>> which is a very serious problem resulting from your bad choice of setup.
>>
>> axel.
>>
>> >
>> >
>> >
>> > With Thanks and Regards,
>> > K Vijay Reddy
>> >
>> >
>> >
>> > ------------------------------------------------------------------------------
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>> > _______________________________________________
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>> > 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.
>
>
>
>
> --
> With Thanks and Regards,
>
> K Vijay Reddy
> Metallurgical and Materials Engineering
> National Institute of Technology
> Rourkela



-- 
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.