88 lines
2.9 KiB
ReStructuredText
88 lines
2.9 KiB
ReStructuredText
.. 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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.. code-block:: LAMMPS
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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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.. code-block:: LAMMPS
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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
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:doc:`smd/wall_surface <fix_smd_wall_surface>` . It updates position
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and velocity for the particles in the group each timestep without
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regard to forces on the particles. The rigid surfaces can thus be
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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 =
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(Rx,Ry,Rz) that goes through a point P = (Px,Py,Pz). The period of the
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rotation is also specified. This style also sets the velocity of each
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particle to (omega cross Rperp) where omega is its angular velocity
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around the rotation axis and Rperp is a perpendicular vector from the
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rotation axis to the particle.
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See `this PDF guide <PDF/MACHDYN_LAMMPS_userguide.pdf>`_ to using Smooth Mach
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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 MACHDYN supports restarting nor
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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 MACHDYN package. It is only enabled if
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LAMMPS was built with that package. See the :doc:`Build package <Build_package>` page 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_vertices>`,
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:doc:`smd/wall_surface <fix_smd_wall_surface>`
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Default
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"""""""
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none
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