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pair_smd_ulsph.txt
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.. index:: pair_style smd/ulsph
pair_style smd/ulsph command
============================
Syntax
""""""
.. parsed-literal::
pair_style smd/ulsph args
* these keywords must be given
keyword = **DENSITY_SUMMATION* or **DENSITY_CONTINUITY* and **VELOCITY_GRADIENT* or **NO_VELOCITY_GRADIENT* and **GRADIENT_CORRECTION* or **NO_GRADIENT_CORRECTION*
Examples
""""""""
pair_style smd/ulsph *DENSITY_CONTINUITY *VELOCITY_GRADIENT *NO_GRADIENT_CORRECTION
Description
"""""""""""
The *smd/ulsph* style computes particle interactions according to continuum mechanics constitutive laws and an updated Lagrangian Smooth-Particle Hydrodynamics algorithm.
This pair style is invoked similar to the following command:
.. parsed-literal::
pair_style smd/ulsph *DENSITY_CONTINUITY *VELOCITY_GRADIENT *NO_GRADIENT_CORRECTION
pair_coeff i j *COMMON rho0 c0 Q1 Cp hg &
*END
Here, *i* and *j* denote the *LAMMPS* particle types for which this pair style is
defined. Note that *i* and *j* can be different, i.e., *ulsph* cross interactions
between different particle types are allowed. However, *i*--*i* respectively *j*--*j* pair_coeff lines have to preceed a cross interaction.
In contrast to the usual *LAMMPS* *pair coeff* definitions, which are given solely a
number of floats and integers, the *ulsph* *pair coeff* definition is organised using
keywords. These keywords mark the beginning of different sets of parameters for particle properties,
material constitutive models, and damage models. The *pair coeff* line must be terminated with
the **END* keyword. The use the line continuation operator *&* is recommended. A typical
invocation of the *ulsph* for a solid body would consist of an equation of state for computing
the pressure (the diagonal components of the stress tensor), and a material model to compute shear
stresses (the off-diagonal components of the stress tensor).
Note that the use of *GRADIENT_CORRECTION can lead to severe numerical instabilities. For a general fluid simulation, *NO_GRADIENT_CORRECTION is recommended.
Please see the `SMD user guide <USER/smd/SMD_LAMMPS_userguide.pdf>`_ for a complete listing of the possible keywords and material models.
----------
**Mixing, shift, table, tail correction, restart, rRESPA info**:
No mixing is performed automatically.
Currently, no part of USER-SMD supports restarting nor minimization.
rRESPA does not apply to this pair style.
----------
Restrictions
""""""""""""
This fix is part of the USER-SMD package. It is only enabled if
LAMMPS was built with that package. See the :ref:`Making LAMMPS <start_3>`
section for more info.
Related commands
""""""""""""""""
:doc:`pair_coeff <pair_coeff>`
**Default:** none
----------
.. _lws: http://lammps.sandia.gov
.. _ld: Manual.html
.. _lc: Section_commands.html#comm
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