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45
doc/pair_body.html
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@ -25,24 +25,26 @@ pair_coeff 1 1 1.0 1.5 2.5
</PRE>
<P><B>Description:</B>
</P>
<P>Style <I>body</I> treats particles which are body particles and computes
pairwise body/body interaction as well as interactions between body
and point-particles. See <A HREF = "Section_howto.html">Section_howto 22</A> of the
<P>Style <I>body</I> is for use with body particles and calculates pairwise
body/body interactions as well as interactions between body and
point-particles. See <A HREF = "Section_howto.html">Section_howto 22</A> of the
manual for an overview of using body particles.
</P>
<P>This pair style is designed for use with the "nparticle" body style,
which is specified as an argument to the "atom-style body" command.
See the <A HREF = "body.html">body</A> doc page for more details about all the body
styles LAMMPS supports. The nparticle style treats a body particle as
a rigid body composed of N sub-particles.
See the <A HREF = "body.html">body</A> doc page for more details about the body
styles LAMMPS supports. The "nparticle" style treats a body particle
as a rigid body composed of N sub-particles.
</P>
<P>The position of a body particle is the position of its center-of-mass
(COM). If the COMs of a pair of body particles are within the cutoff
(global or type-specific, as specified above), then all interactions
between pairs of sub-particles in the two body particles are computed.
<P>The coordinates of a body particle are its center-of-mass (COM). If
the COMs of a pair of body particles are within the cutoff (global or
type-specific, as specified above), then all interactions between
pairs of sub-particles in the two body particles are computed.
E.g. if the first body particle has 3 sub-particles, and the second
has 10, then 30 interactions are computed to sum the total force and
torque on each body particle. Note that all 30 interactions are
has 10, then 30 interactions are computed and summed to yield the
total force and torque on each body particle.
</P>
<P>IMPORTANT NOTE: In the example just described, all 30 interactions are
computed even if the distance between a particular pair of
sub-particles is greater than the cutoff. Likewise, no interaction
between two body particles is computed if the two COMs are further
@ -55,15 +57,18 @@ shape and size.
particle. The distance between the two particles is calculated using
the COM of the body particle and the position of the point particle.
If the distance is within the cutoff and the body particle has N
sub-particles, then N interactions are computed with the point
particle. If the distance is not within the cutoff, no interactions
between the body and point particle are computed.
sub-particles, then N interactions with the point particle are
computed and summed. If the distance is not within the cutoff, no
interactions between the body and point particle are computed.
</P>
<P>The interaction between two sub-particles (or a sub-particle and point
particle) is computed as a Lennard-Jones interaction, using the
standard formula on the <A HREF = "pair_lj.html">pair_style lj/cut</A> doc page.
The espilon and sigma values are based on the atom type of the parent
body particle.
<P>The interaction between two sub-particles, or a sub-particle and point
particle, or betwee two point particles is computed as a Lennard-Jones
interaction, using the standard formula
</P>
<CENTER><IMG SRC = "Eqs/pair_lj.jpg">
</CENTER>
<P>where Rc is the cutoff. As explained above, an interaction involving
one or two body sub-particles may be computed even for r > Rc.
</P>
<P>For style <I>body</I>, the following coefficients must be defined for each
pair of atoms types via the <A HREF = "pair_coeff.html">pair_coeff</A> command as in

45
doc/pair_body.txt
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@ -22,24 +22,26 @@ pair_coeff 1 1 1.0 1.5 2.5 :pre
[Description:]
Style {body} treats particles which are body particles and computes
pairwise body/body interaction as well as interactions between body
and point-particles. See "Section_howto 22"_Section_howto.html of the
Style {body} is for use with body particles and calculates pairwise
body/body interactions as well as interactions between body and
point-particles. See "Section_howto 22"_Section_howto.html of the
manual for an overview of using body particles.
This pair style is designed for use with the "nparticle" body style,
which is specified as an argument to the "atom-style body" command.
See the "body"_body.html doc page for more details about all the body
styles LAMMPS supports. The nparticle style treats a body particle as
a rigid body composed of N sub-particles.
See the "body"_body.html doc page for more details about the body
styles LAMMPS supports. The "nparticle" style treats a body particle
as a rigid body composed of N sub-particles.
The position of a body particle is the position of its center-of-mass
(COM). If the COMs of a pair of body particles are within the cutoff
(global or type-specific, as specified above), then all interactions
between pairs of sub-particles in the two body particles are computed.
The coordinates of a body particle are its center-of-mass (COM). If
the COMs of a pair of body particles are within the cutoff (global or
type-specific, as specified above), then all interactions between
pairs of sub-particles in the two body particles are computed.
E.g. if the first body particle has 3 sub-particles, and the second
has 10, then 30 interactions are computed to sum the total force and
torque on each body particle. Note that all 30 interactions are
has 10, then 30 interactions are computed and summed to yield the
total force and torque on each body particle.
IMPORTANT NOTE: In the example just described, all 30 interactions are
computed even if the distance between a particular pair of
sub-particles is greater than the cutoff. Likewise, no interaction
between two body particles is computed if the two COMs are further
@ -52,15 +54,18 @@ Similar rules apply for a body particle interacting with a point
particle. The distance between the two particles is calculated using
the COM of the body particle and the position of the point particle.
If the distance is within the cutoff and the body particle has N
sub-particles, then N interactions are computed with the point
particle. If the distance is not within the cutoff, no interactions
between the body and point particle are computed.
sub-particles, then N interactions with the point particle are
computed and summed. If the distance is not within the cutoff, no
interactions between the body and point particle are computed.
The interaction between two sub-particles (or a sub-particle and point
particle) is computed as a Lennard-Jones interaction, using the
standard formula on the "pair_style lj/cut"_pair_lj.html doc page.
The espilon and sigma values are based on the atom type of the parent
body particle.
The interaction between two sub-particles, or a sub-particle and point
particle, or betwee two point particles is computed as a Lennard-Jones
interaction, using the standard formula
:c,image(Eqs/pair_lj.jpg)
where Rc is the cutoff. As explained above, an interaction involving
one or two body sub-particles may be computed even for r > Rc.
For style {body}, the following coefficients must be defined for each
pair of atoms types via the "pair_coeff"_pair_coeff.html command as in