"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

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pair_style peri/pmb command :h3
pair_style peri/pmb/omp command :h3
pair_style peri/lps command :h3
pair_style peri/lps/omp command :h3

[Syntax:]

pair_style style :pre 

style = {peri/pmb} or {peri/lps} :ul

[Examples:]

pair_style peri/pmb
pair_coeff * * 1.6863e22 0.0015001 0.0005 0.25 :pre

pair_style peri/lps
pair_coeff * * 14.9e9 14.9e9 0.0015001 0.0005 0.25 :pre

[Description:]

The peridynamic pair styles implement material models that can be used
at the mescscopic and macroscopic scales.

Style {peri/pmb} implements the Peridynamic bond-based prototype
microelastic brittle (PMB) model.

Style {peri/lps} implements the Peridynamic state-based linear
peridynamic solid (LPS) model.

The canonical papers on Peridynamics are "(Silling 2000)"_#Silling2000
and "(Silling 2007)"_#Silling2007.  The implementation of Peridynamics
in LAMMPS is described in "(Parks)"_#Parks.  Also see the "PDLAMMPS
user guide"_http://www.sandia.gov/~mlparks/papers/PDLAMMPS.pdf for
more details about the implementation of peridynamics in LAMMPS.

The following coefficients must be defined for each pair of atom types
via the "pair_coeff"_pair_coeff.html command as in the examples above,
or in the data file or restart files read by the
"read_data"_read_data.html or "read_restart"_read_restart.html
commands, or by mixing as described below.

For the {peri/pmb} style:

c (energy/distance/volume^2 units)
horizon (distance units)
s00 (unitless)
alpha (unitless) :ul

C is the effectively a spring constant for Peridynamic bonds, the
horizon is a cutoff distance for truncating interactions, and s00 and
alpha are used as a bond breaking criteria.  The units of c are such
that c/distance = stiffness/volume^2, where stiffness is
energy/distance^2 and volume is distance^3.  See the users guide for
more details.

For the {peri/lps} style:

K (force/area units)
G (force/area units)
horizon (distance units)
s00 (unitless)
alpha (unitless) :ul

K is the bulk modulus and G is the shear modulus.  The horizon is a
cutoff distance for truncating interactions, and s00 and alpha are
used as a bond breaking criteria. See the users guide for more
details.

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Styles with a {cuda}, {gpu}, {omp}, or {opt} suffix are functionally
the same as the corresponding style without the suffix.  They have
been optimized to run faster, depending on your available hardware, as
discussed in "Section_accelerate"_Section_accelerate.html of the
manual.  The accelerated styles take the same arguments and should
produce the same results, except for round-off and precision issues.

These accelerated styles are part of the USER-CUDA, GPU, USER-OMP and OPT
packages, respectively.  They are only enabled if LAMMPS was built with
those packages.  See the "Making LAMMPS"_Section_start.html#start_3
section for more info.

You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the "-suffix command-line
switch"_Section_start.html#start_7 when you invoke LAMMPS, or you can
use the "suffix"_suffix.html command in your input script.

See "Section_accelerate"_Section_accelerate.html of the manual for
more instructions on how to use the accelerated styles effectively.

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[Mixing, shift, table, tail correction, restart, rRESPA info]:

These pair styles do not support mixing.  Thus, coefficients for all
I,J pairs must be specified explicitly.

These pair styles do not support the "pair_modify"_pair_modify.html
shift option.

The "pair_modify"_pair_modify.html table and tail options are not
relevant for these pair styles.

These pair styles write their information to "binary restart
files"_restart.html, so pair_style and pair_coeff commands do not need
to be specified in an input script that reads a restart file.

These pair styles can only be used via the {pair} keyword of the
"run_style respa"_run_style.html command.  They do not support the
{inner}, {middle}, {outer} keywords.

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[Restrictions:]

The {peri/pmb} and {peri/lps} styles are part of the PERI
package. They are only enabled if LAMMPS was built with that package.
See the "Making LAMMPS"_Section_start.html#start_3 section for more
info.

[Related commands:]

"pair_coeff"_pair_coeff.html

[Default:] none

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:link(Parks)
[(Parks)] Parks, Lehoucq, Plimpton, Silling, Comp Phys Comm, 179(11), 777-783 (2008).

:link(Silling2000)
[(Silling 2000)] Silling, J Mech Phys Solids, 48, 175-209 (2000).

:link(Silling2007)
[(Silling 2007)] Silling, Epton, Weckner, Xu, Askari, J Elasticity, 88, 151-184 (2007).
