2014-02-13 02:05:01 +08:00
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"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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compute dilatation/atom command :h3
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[Syntax:]
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compute ID group-ID dilatation/atom :pre
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ID, group-ID are documented in compute command
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dilation/atom = style name of this compute command :ul
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[Examples:]
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compute 1 all dilatation/atom :pre
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[Description:]
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Define a computation that calculates the per-atom dilatation for each
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atom in a group. This is a quantity relevant for "Peridynamics
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2014-02-13 07:25:05 +08:00
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models"_pair_peri.html. See "this document"_PDF/PDLammps_overview.pdf
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for an overview of LAMMPS commands for Peridynamics modeling.
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2014-02-13 02:05:01 +08:00
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For small deformation, dilatation of is the measure of the volumetric
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strain.
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The dilatation "theta" for each peridynamic particle I is calculated
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as a sum over its neighbors with unbroken bonds, where the
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contribution of the IJ pair is a function of the change in bond length
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(versus the initial length in the reference state), the volume
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fraction of the particles and an influence function. See the
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"PDLAMMPS user
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guide"_http://www.sandia.gov/~mlparks/papers/PDLAMMPS.pdf for a formal
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definition of dilatation.
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This command can only be used with a subset of the Peridynamic "pair
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styles"_pair_peri.html: peri/lps, peri/ves and peri/eps.
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The dilatation value will be 0.0 for atoms not in the specified
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compute group.
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[Output info:]
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This compute calculates a per-atom vector, which can be accessed by
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any command that uses per-atom values from a compute as input. See
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Section_howto 15 for an overview of LAMMPS output options.
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The per-atom vector values are unitlesss numbers (theta) >= 0.0.
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[Restrictions:]
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This compute is part of the PERI package. It is only enabled if
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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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"compute damage"_compute_damage.html, "compute
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plasticity"_compute_plasticity.html
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[Default:] none
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