forked from lijiext/lammps
Update fix_eco_force.rst
This commit is contained in:
vmohles
parent
8e46c53d57
commit
def79f246a
|
|
@ -1,15 +1,30 @@
|
|||
1 fix eco/force command
|
||||
.. index:: fix eco/force
|
||||
|
||||
fix ID group-ID eco/force u0 eta rcut file
|
||||
• ID, group-ID are documented in fix command
|
||||
• u0 = energy added to each atom (energy units)
|
||||
• eta = cutoff value (usually 0.25)
|
||||
• rcut = cutoff radius for orientation parameter calculation • file = file that specifies orientation of each grain
|
||||
Examples: fix gb all eco/force 0.08 0.25 3.524 sigma5.ori
|
||||
fix eco/force command
|
||||
=====================
|
||||
|
||||
|
||||
.. parsed-literal::
|
||||
|
||||
1.1 Description:
|
||||
fix ID group-ID eco/force u0 eta rcut file
|
||||
|
||||
|
||||
* ID, group-ID are documented in fix command
|
||||
* u0 = energy added to each atom (energy units)
|
||||
* eta = cutoff value (usually 0.25)
|
||||
* rcut = cutoff radius for orientation parameter calculation
|
||||
* file = file that specifies orientation of each grain
|
||||
|
||||
Examples
|
||||
""""""""
|
||||
|
||||
.. code-block:: LAMMPS
|
||||
|
||||
fix gb all eco/force 0.08 0.25 3.524 sigma5.ori
|
||||
|
||||
|
||||
Description
|
||||
"""""""""""
|
||||
|
||||
The fix applies a synthetic driving force to a grain boundary which can
|
||||
be used for the investigation of grain boundary motion. The affiliation
|
||||
|
|
@ -28,6 +43,8 @@ described in (Ulomek), the implementation follows the efficient
|
|||
implementation from (Schratt & Mohles). The synthetic potential energy added to an
|
||||
atom j is given by the following formulas
|
||||
|
||||
.. math::
|
||||
|
||||
\begin{eqnarray}
|
||||
w(|\vec{r}_{jk}|)=w_{jk}=\left\{\begin{array}{lc}
|
||||
\frac{|\vec{r}_{jk}|^{4}}{r_{\mathrm{cut}}^{4}}-2\frac{|\vec{r}_{jk}|^{2}}{r_{\mathrm{cut}}^{2}}+1, & |\vec{r}_{jk}|<r_{\mathrm{cut}} \\
|
||||
|
|
@ -51,7 +68,8 @@ u(\chi_{j}) & = & \frac{u_{0}}{2}\left\{\begin{array}{lc}
|
|||
\label{eq:energy-mid}
|
||||
\end{eqnarray}
|
||||
|
||||
which are fully explained in (Ulomek) and (Schratt & Mohles).
|
||||
which are fully explained in :ref: `(Ulomek) <Ulomek>`
|
||||
and `(Schratt & Mohles) <Schratt>`.
|
||||
|
||||
The force on each atom is the negative gradient of the synthetic potential energy. It
|
||||
depends on the surrounding of this atom. An atom far from the grain boundary does not
|
||||
|
|
@ -85,12 +103,13 @@ simulation.
|
|||
|
||||
|
||||
|
||||
1.2 Restart, fix_modify, output, run start/stop, minimize info:
|
||||
**Restart, fix_modify, output, run start/stop, minimize info:**
|
||||
|
||||
No information about this fix is written to binary restart files. The
|
||||
fix_modify energy option is supported by this fix to add the potential energy of
|
||||
atominteractions with the grain boundary driving force to the system's poten-
|
||||
tial energy as part of thermodynamic output.
|
||||
No information about this fix is written to :doc: `binary restart files`.
|
||||
|
||||
The :doc:`fix_modify <fix_modify>` *energy* option is supported by this fix to
|
||||
add the potential energy of atom interactions with the grain boundary
|
||||
driving force to the system's potential energy as part of thermodynamic output.
|
||||
The total sum of added synthetic potential energy is computed and can be accessed
|
||||
by various output options. The order parameter as well as the thermally masked
|
||||
output parameter are stored in per-atom arrays and can also be accessed by various
|
||||
|
|
@ -101,26 +120,43 @@ not invoked during energy minimization.
|
|||
|
||||
|
||||
|
||||
1.3 Restrictions:
|
||||
Restrictions
|
||||
""""""""""""
|
||||
|
||||
This fix is part of the MISC package. It is only enabled if LAMMPS was
|
||||
built with that package. See the Making LAMMPS section for more info.
|
||||
|
||||
|
||||
|
||||
1.4 Related commands:
|
||||
Related commands
|
||||
""""""""""""""""
|
||||
|
||||
fix_modify
|
||||
Default: none
|
||||
(Ulomek) Felix Ulomek et al. Modelling Simul. Mater. Sci. Eng. 23 (2015) 025007
|
||||
(Schratt & Mohles) Adrian A. Schratt and Volker Mohles. Comp. Mat. Sci. 182 (2020) 109774
|
||||
:doc:`fix_modify <fix_modify>`
|
||||
|
||||
For illustration purposes, here is an example file that specifies a $\Sigma5\langle001\rangle$ tilt grain boundary.
|
||||
**Default:** none
|
||||
|
||||
----------
|
||||
|
||||
.. _Ulomek:
|
||||
|
||||
**(Ulomek)** Ulomek, Brien, Foiles, Mohles, Modelling Simul. Mater. Sci. Eng. 23 (2015) 025007
|
||||
|
||||
.. _Schratt:
|
||||
|
||||
**(Schratt)** Schratt, Mohles. Comp. Mat. Sci. 182 (2020) 109774
|
||||
|
||||
----------
|
||||
|
||||
|
||||
For illustration purposes, here is an example file that specifies a
|
||||
Sigma=5 <001> tilt grain boundary.
|
||||
This is for a lattice constant of 3.52 Angs.
|
||||
|
||||
|
||||
file:
|
||||
|
||||
.. parsed-literal::
|
||||
|
||||
1.5 File:
|
||||
1.671685 0.557228 1.76212
|
||||
0.557228 -1.671685 1.76212
|
||||
2.228913 -1.114456 0.000000
|
||||
|
|
@ -128,3 +164,4 @@ This is for a lattice constant of 3.52 Angs.
|
|||
1.671685 -0.557228 1.76212
|
||||
2.228913 1.114456 0.000000
|
||||
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue