forked from lijiext/lammps
87 lines
2.8 KiB
Plaintext
87 lines
2.8 KiB
Plaintext
.. index:: pair_style smd/ulsph
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pair_style smd/ulsph 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 smd/ulsph args
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* these keywords must be given
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keyword = **DENSITY_SUMMATION* or **DENSITY_CONTINUITY* and **VELOCITY_GRADIENT* or **NO_VELOCITY_GRADIENT* and **GRADIENT_CORRECTION* or **NO_GRADIENT_CORRECTION*
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Examples
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""""""""
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pair_style smd/ulsph *DENSITY_CONTINUITY *VELOCITY_GRADIENT *NO_GRADIENT_CORRECTION
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Description
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"""""""""""
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The *smd/ulsph* style computes particle interactions according to continuum mechanics constitutive laws and an updated Lagrangian Smooth-Particle Hydrodynamics algorithm.
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This pair style is invoked similar to the following command:
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.. parsed-literal::
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pair_style smd/ulsph *DENSITY_CONTINUITY *VELOCITY_GRADIENT *NO_GRADIENT_CORRECTION
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pair_coeff i j *COMMON rho0 c0 Q1 Cp hg &
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*END
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Here, *i* and *j* denote the *LAMMPS* particle types for which this pair style is
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defined. Note that *i* and *j* can be different, i.e., *ulsph* cross interactions
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between different particle types are allowed. However, *i*\ --\ *i* respectively *j*\ --\ *j* pair_coeff lines have to preceed a cross interaction.
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In contrast to the usual *LAMMPS* *pair coeff* definitions, which are given solely a
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number of floats and integers, the *ulsph* *pair coeff* definition is organised using
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keywords. These keywords mark the beginning of different sets of parameters for particle properties,
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material constitutive models, and damage models. The *pair coeff* line must be terminated with
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the **END* keyword. The use the line continuation operator *&* is recommended. A typical
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invocation of the *ulsph* for a solid body would consist of an equation of state for computing
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the pressure (the diagonal components of the stress tensor), and a material model to compute shear
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stresses (the off-diagonal components of the stress tensor).
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Note that the use of *GRADIENT_CORRECTION can lead to severe numerical instabilities. For a general fluid simulation, *NO_GRADIENT_CORRECTION is recommended.
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Please see the `SMD user guide <USER/smd/SMD_LAMMPS_userguide.pdf>`_ for a complete listing of the possible keywords and material models.
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----------
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**Mixing, shift, table, tail correction, restart, rRESPA info**\ :
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No mixing is performed automatically.
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Currently, no part of USER-SMD supports restarting nor minimization.
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rRESPA does not apply to this pair style.
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----------
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Restrictions
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""""""""""""
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This fix is part of the USER-SMD package. It is only enabled if
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LAMMPS was built with that package. See the :ref:`Making LAMMPS <start_3>`
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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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.. _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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