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


From: Vijay Reddy <vijay00vegeta@...24...>
Date: Sat, 14 Apr 2018 20:05:12 +0530

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).

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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--
Dr. Axel Kohlmeyer  akohlmey@...43...4...  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