forked from lijiext/lammps
87 lines
2.9 KiB
Plaintext
87 lines
2.9 KiB
Plaintext
.. index:: fix smd/move_tri_surf
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fix smd/move_tri_surf command
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=============================
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Syntax
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""""""
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.. parsed-literal::
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fix ID group-ID smd/move_tri_surf keyword
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* ID, group-ID are documented in :doc:`fix <fix>` command
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* smd/move_tri_surf keyword = style name of this fix command
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* keyword = **LINEAR* or **WIGGLE* or **ROTATE*
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.. parsed-literal::
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**LINEAR* args = Vx Vy Vz
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Vx,Vy,Vz = components of velocity vector (velocity units), any component can be specified as NULL
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**WIGGLE* args = Vx Vy Vz max_travel
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vx,vy,vz = components of velocity vector (velocity units), any component can be specified as NULL
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max_travel = wiggle amplitude
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**ROTATE* args = Px Py Pz Rx Ry Rz period
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Px,Py,Pz = origin point of axis of rotation (distance units)
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Rx,Ry,Rz = axis of rotation vector
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period = period of rotation (time units)
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Examples
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""""""""
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.. parsed-literal::
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fix 1 tool smd/move_tri_surf *LINEAR 20 20 10
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fix 2 tool smd/move_tri_surf *WIGGLE 20 20 10
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fix 2 tool smd/move_tri_surf *ROTATE 0 0 0 5 2 1
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Description
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"""""""""""
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This fix applies only to rigid surfaces read from .STL files via fix :doc:`smd/wall_surface <fix_smd_wall_surface>` .
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It updates position and velocity for the particles in the group each timestep without regard to forces on the particles.
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The rigid surfaces can thus be moved along simple trajectories during the simulation.
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The **LINEAR* style moves particles with the specified constant velocity
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vector V = (Vx,Vy,Vz). This style also sets the velocity of each particle
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to V = (Vx,Vy,Vz).
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The **WIGGLE* style moves particles in an oscillatory fashion.
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Particles are moved along (vx, vy, vz) with constant velocity until a
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displacement of max_travel is reached. Then, the velocity vector is
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reversed. This process is repeated.
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The **ROTATE* style rotates particles around a rotation axis R = (Rx,Ry,Rz) that
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goes through a point P = (Px,Py,Pz). The period of the rotation is also
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specified. This style also sets the velocity of each particle to (omega cross
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Rperp) where omega is its angular velocity around the rotation axis and
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Rperp is a perpendicular vector from the rotation axis to the particle.
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See `this PDF guide <USER/smd/SMD_LAMMPS_userguide.pdf>`_ to using Smooth Mach Dynamics in LAMMPS.
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Restart, fix_modify, output, run start/stop, minimize info
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""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
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Currently, no part of USER-SMD supports restarting nor minimization. This fix has no outputs.
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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:`smd/triangle_mesh_vertices <compute_smd_triangle_mesh_vertices>`, :doc:`smd/wall_surface <fix_smd_wall_surface>`
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**Default:** none
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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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