forked from lijiext/lammps
186 lines
6.0 KiB
Plaintext
186 lines
6.0 KiB
Plaintext
"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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pair_style peri/pmb command :h3
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pair_style peri/pmb/omp command :h3
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pair_style peri/lps command :h3
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pair_style peri/lps/omp command :h3
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pair_style peri/ves command :h3
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[Syntax:]
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pair_style style :pre
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style = {peri/pmb} or {peri/lps} or {peri/ves} :ul
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[Examples:]
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pair_style peri/pmb
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pair_coeff * * 1.6863e22 0.0015001 0.0005 0.25 :pre
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pair_style peri/lps
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pair_coeff * * 14.9e9 14.9e9 0.0015001 0.0005 0.25 :pre
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pair_style peri/ves
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pair_coeff * * 14.9e9 14.9e9 0.0015001 0.0005 0.25 0.5 0.001 :pre
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[Description:]
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The peridynamic pair styles implement material models that can be used
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at the mescscopic and macroscopic scales.
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Style {peri/pmb} implements the Peridynamic bond-based prototype
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microelastic brittle (PMB) model.
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Style {peri/lps} implements the Peridynamic state-based linear
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peridynamic solid (LPS) model.
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Style {peri/ves} implements the Peridynamic state-based linear
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peridynamic viscoelastic solid (VES) model.
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The canonical papers on Peridynamics are "(Silling 2000)"_#Silling2000
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and "(Silling 2007)"_#Silling2007. The implementation of Peridynamics
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in LAMMPS is described in "(Parks)"_#Parks. Also see the "PDLAMMPS
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user guide"_http://www.sandia.gov/~mlparks/papers/PDLAMMPS.pdf for
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more details about the implementation of peridynamics in LAMMPS.
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The peridynamic VES model in PDLAMMPS is implemented by R. Rahman and
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J.T Foster at University of Texas at San Antonio. The VES formulation
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is described in "(Mitchell)"_#Mitchell. An additional PDF doc with
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details is in "doc/PDF/PDLammps_VES.pdf"_PDF/PDLammps_VES.pdf. For
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questions regarding VES implementation in LAMMPS please contact Rezwan
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Rahman: rezwanur.rahman at utsa.edu.
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The following coefficients must be defined for each pair of atom types
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via the "pair_coeff"_pair_coeff.html command as in the examples above,
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or in the data file or restart files read by the
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"read_data"_read_data.html or "read_restart"_read_restart.html
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commands, or by mixing as described below.
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For the {peri/pmb} style:
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c (energy/distance/volume^2 units)
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horizon (distance units)
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s00 (unitless)
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alpha (unitless) :ul
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C is the effectively a spring constant for Peridynamic bonds, the
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horizon is a cutoff distance for truncating interactions, and s00 and
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alpha are used as a bond breaking criteria. The units of c are such
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that c/distance = stiffness/volume^2, where stiffness is
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energy/distance^2 and volume is distance^3. See the users guide for
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more details.
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For the {peri/lps} style:
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K (force/area units)
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G (force/area units)
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horizon (distance units)
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s00 (unitless)
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alpha (unitless) :ul
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K is the bulk modulus and G is the shear modulus. The horizon is a
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cutoff distance for truncating interactions, and s00 and alpha are
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used as a bond breaking criteria. See the users guide for more
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details.
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For the {peri/ves} style:
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K (force/area units)
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G (force/area units)
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horizon (distance units)
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s00 (unitless)
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alpha (unitless)
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m_lambdai (unitless)
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m_taubi (unitless) :ul
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The same as for {peri/lps}, K is the bulk modulus and G is the shear
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modulus. The horizon is a cutoff distance for truncating interactions,
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and s00 and alpha are used as a bond breaking criteria. m_lambdai and
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m_taubi are the viscoelastic relaxation parameter and time constant,
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respectively. m_lambdai varies within zero to one. For very small
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values of m_lambdai the viscoelsatic model responds very similar to a
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linear elastic model. For details see the description in
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"(Mitchell)"_#Mitchell.
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:line
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Styles with a {cuda}, {gpu}, {omp}, or {opt} suffix are functionally
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the same as the corresponding style without the suffix. They have
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been optimized to run faster, depending on your available hardware, as
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discussed in "Section_accelerate"_Section_accelerate.html of the
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manual. The accelerated styles take the same arguments and should
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produce the same results, except for round-off and precision issues.
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These accelerated styles are part of the USER-CUDA, GPU, USER-OMP and OPT
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packages, respectively. They are only enabled if LAMMPS was built with
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those packages. See the "Making LAMMPS"_Section_start.html#start_3
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section for more info.
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You can specify the accelerated styles explicitly in your input script
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by including their suffix, or you can use the "-suffix command-line
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switch"_Section_start.html#start_7 when you invoke LAMMPS, or you can
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use the "suffix"_suffix.html command in your input script.
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See "Section_accelerate"_Section_accelerate.html of the manual for
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more instructions on how to use the accelerated styles effectively.
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:line
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[Mixing, shift, table, tail correction, restart, rRESPA info]:
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These pair styles do not support mixing. Thus, coefficients for all
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I,J pairs must be specified explicitly.
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These pair styles do not support the "pair_modify"_pair_modify.html
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shift option.
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The "pair_modify"_pair_modify.html table and tail options are not
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relevant for these pair styles.
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These pair styles write their information to "binary restart
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files"_restart.html, so pair_style and pair_coeff commands do not need
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to be specified in an input script that reads a restart file.
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These pair styles can only be used via the {pair} keyword of the
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"run_style respa"_run_style.html command. They do not support the
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{inner}, {middle}, {outer} keywords.
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:line
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[Restrictions:]
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The {peri/pmb}, {peri/lps} and {peri/ves} styles are part of the PERI
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package. They are only enabled if LAMMPS was built with that package.
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See the "Making LAMMPS"_Section_start.html#start_3 section for more
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info.
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[Related commands:]
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"pair_coeff"_pair_coeff.html
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[Default:] none
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:line
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:link(Parks)
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[(Parks)] Parks, Lehoucq, Plimpton, Silling, Comp Phys Comm, 179(11),
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777-783 (2008).
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:link(Silling2000)
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[(Silling 2000)] Silling, J Mech Phys Solids, 48, 175-209 (2000).
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:link(Silling2007)
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[(Silling 2007)] Silling, Epton, Weckner, Xu, Askari, J Elasticity,
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88, 151-184 (2007).
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:link(Mitchell)
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[(Mitchell)] Mitchell, "A non-local, ordinary-state-based
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viscoelasticity model for peridynamics", Sandia National Lab Report,
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8064:1-28 (2011).
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