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Adding hybrid support to BPM, more doc pages

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jtclemm
2024-04-04 09:42:10 -06:00
parent 08db64c27f
commit ceec24d50b
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doc/src/pair_rheo_solid.rst
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@ -21,36 +21,88 @@ Examples
Description
"""""""""""
pair style...
Style *rheo/solid* is effectively a copy of pair style
:doc:`bpm/spring <pair_bpm_spring>` except it only applies forces
between solid RHEO particles, determined by checking the status of
each pair of neighboring particles before calculating forces.
The style computes pairwise forces with the formula
.. math::
F = k (r - r_c)
where :math:`k` is a stiffness and :math:`r_c` is the cutoff length.
An additional damping force is also applied to interacting
particles. The force is proportional to the difference in the
normal velocity of particles
.. math::
F_D = - \gamma w (\hat{r} \bullet \vec{v})
where :math:`\gamma` is the damping strength, :math:`\hat{r}` is the
radial normal vector, :math:`\vec{v}` is the velocity difference
between the two particles, and :math:`w` is a smoothing factor.
This smoothing factor is constructed such that damping forces go to zero
as particles come out of contact to avoid discontinuities. It is
given by
.. math::
w = 1.0 - \left( \frac{r}{r_c} \right)^8 .
The following coefficients must be defined for each pair of atom types
via the :doc:`pair_coeff <pair_coeff>` command as in the examples
above, or in the data file or restart files read by the
:doc:`read_data <read_data>` or :doc:`read_restart <read_restart>`
commands, or by mixing as described below:
* :math:`k` (force/distance units)
* :math:`r_c` (distance units)
* :math:`\gamma` (force/velocity units)
* :math:`k` (force/distance units)
* :math:`\sigma` (distance units)
* :math:`\gamma` (force/velocity units)
----------
Mixing, shift, table, tail correction, restart, rRESPA info
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
This style does not support the :doc:`pair_modify <pair_modify>`
shift, table, and tail options.
For atom type pairs I,J and I != J, the A coefficient and cutoff
distance for this pair style can be mixed. A is always mixed via a
*geometric* rule. The cutoff is mixed according to the pair_modify
mix value. The default mix value is *geometric*\ . See the
"pair_modify" command for details.
This style does not write information to :doc:`binary restart files <restart>`. Thus, you need to re-specify the pair_style and
pair_coeff commands in an input script that reads a restart file.
This pair style does not support the :doc:`pair_modify <pair_modify>`
shift option, since the pair interaction goes to 0.0 at the cutoff.
This style can only be used via the *pair* keyword of the :doc:`run_style respa <run_style>` command. It does not support the *inner*, *middle*, *outer* keywords.
The :doc:`pair_modify <pair_modify>` table and tail options are not
relevant for this pair style.
This pair style writes its information to :doc:`binary restart files
<restart>`, so pair_style and pair_coeff commands do not need to be
specified in an input script that reads a restart file.
This pair style can only be used via the *pair* keyword of the
:doc:`run_style respa <run_style>` command. It does not support the
*inner*, *middle*, *outer* keywords.
----------
Restrictions
""""""""""""
This fix is part of the RHEO package. It is only enabled if
LAMMPS was built with that package. See the :doc:`Build package <Build_package>` page for more info.
This pair style is part of the BPM package. It is only enabled if
LAMMPS was built with that package. See the :doc:`Build package
<Build_package>` page for more info.
Related commands
""""""""""""""""
:doc:`fix rheo <fix_rheo>`,
:doc:`pair bpm/spring <pair_bpm_spring>`,
:doc:`fix rheo/thermal <fix_rheo_thermal>`,
:doc:`pair bpm/spring <pair_bpm_spring>`
Default
"""""""