forked from lijiext/lammps
260 lines
7.4 KiB
Plaintext
260 lines
7.4 KiB
Plaintext
.. index:: pair_style peri/pmb
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pair_style peri/pmb command
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===========================
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pair_style peri/pmb/omp command
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===============================
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pair_style peri/lps command
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===========================
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pair_style peri/lps/omp command
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===============================
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pair_style peri/ves command
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===========================
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pair_style peri/eps command
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===========================
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Syntax
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""""""
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.. parsed-literal::
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pair_style style
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* style = *peri/pmb* or *peri/lps* or *peri/ves* or *peri/eps*
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Examples
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""""""""
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.. parsed-literal::
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pair_style peri/pmb
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pair_coeff * * 1.6863e22 0.0015001 0.0005 0.25
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.. parsed-literal::
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pair_style peri/lps
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pair_coeff * * 14.9e9 14.9e9 0.0015001 0.0005 0.25
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.. parsed-literal::
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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
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.. parsed-literal::
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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
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Description
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"""""""""""
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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 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 :ref:`(Silling 2000) <Silling2000>`
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and :ref:`(Silling 2007) <Silling2007>`. The implementation of Peridynamics
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in LAMMPS is described in :ref:`(Parks) <Parks>`. Also see the `PDLAMMPS 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 :doc:`pair_coeff <pair_coeff>` 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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:doc:`read_data <read_data>` or :doc:`read_restart <read_restart>`
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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)
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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)
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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)
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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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----------
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Styles with a *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 :doc:`Section_accelerate <Section_accelerate>`
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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 GPU, USER-INTEL, KOKKOS,
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USER-OMP and OPT packages, respectively. They are only enabled if
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LAMMPS was built with those packages. See the :ref:`Making LAMMPS <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 :ref:`-suffix command-line switch <start_7>` when you invoke LAMMPS, or you can
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use the :doc:`suffix <suffix>` command in your input script.
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See :doc:`Section_accelerate <Section_accelerate>` of the manual for
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more instructions on how to use the accelerated styles effectively.
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----------
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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 :doc:`pair_modify <pair_modify>`
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shift option.
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The :doc:`pair_modify <pair_modify>` 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 :doc:`binary restart files <restart>`, 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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:doc:`run_style respa <run_style>` command. They do not support the
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*inner*\ , *middle*\ , *outer* keywords.
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----------
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Restrictions
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""""""""""""
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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 :ref:`Making LAMMPS <start_3>` section for more info.
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Related commands
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""""""""""""""""
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:doc:`pair_coeff <pair_coeff>`
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**Default:** none
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----------
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.. _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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.. _Silling2000:
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**(Silling 2000)** Silling, J Mech Phys Solids, 48, 175-209 (2000).
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.. _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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.. _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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.. _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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.. _lws: http://lammps.sandia.gov
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.. _ld: Manual.html
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.. _lc: Section_commands.html#comm
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