forked from lijiext/lammps
217 lines
7.1 KiB
Plaintext
217 lines
7.1 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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pair_style peri/eps 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} or {peri/eps}: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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pair_style peri/eps
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pair_coeff * * 14.9e9 14.9e9 0.0015001 0.0005 0.25 118.43 :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. See "this
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document"_PDF/PDLammps_overview.pdf for an overview of LAMMPS commands
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for Peridynamics modeling.
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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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Style {peri/eps} implements the Peridynamic state-based elastic-plastic
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solid (EPS) 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 its implementation.
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The peridynamic VES and EPS models in PDLAMMPS were implemented by
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R. Rahman and J. T. Foster at University of Texas at San Antonio. The
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original VES formulation is described in "(Mitchell2011)" and the
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original EPS formulation is in "(Mitchell2011a)". Additional PDF docs
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that describe the VES and EPS implementations are include in the
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LAMMPS distro in "doc/PDF/PDLammps_VES.pdf"_PDF/PDLammps_VES.pdf and
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"doc/PDF/PDLammps_EPS.pdf"_PDF/PDLammps_EPS.pdf. For questions
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regarding the VES and EPS models in LAMMPS you can contact R. Rahman
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(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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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. m_lambdai and m_taubi are the
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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 please see the description in
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"(Mtchell2011)".
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For the {peri/eps} 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_yield_stress (force/area units)
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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 and s00 and alpha are used as a bond breaking
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criteria. m_yield_stress is the yield stress of the material. For
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details please see the description in "(Mtchell2011a)".
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:line
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Styles with a {cuda}, {gpu}, {intel}, {kk}, {omp}, or {opt} suffix are
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functionally the same as the corresponding style without the suffix.
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They have been optimized to run faster, depending on your available
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hardware, as discussed in "Section_accelerate"_Section_accelerate.html
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of the manual. The accelerated styles take the same arguments and
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should produce the same results, except for round-off and precision
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issues.
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These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
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KOKKOS, USER-OMP and OPT packages, respectively. They are only
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enabled if LAMMPS was built with those packages. See the "Making
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LAMMPS"_Section_start.html#start_3 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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All of these styles are part of the PERI package. They are only
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enabled if LAMMPS was built with that package. See the "Making
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LAMMPS"_Section_start.html#start_3 section for more 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(Mitchell2011)
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[(Mitchell2011)] 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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:link(Mitchell2011a)
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[(Mitchell2011a)] Mitchell. A Nonlocal, Ordinary, State-Based
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Plasticity Model for Peridynamics. Sandia National Lab Report,
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3166:1-34 (2011).
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