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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@2665 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp 2009-03-17 23:25:23 +00:00
parent 595f8b08d5
commit ef1b146efb
2 changed files with 68 additions and 6 deletions
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37
doc/fix_deform.html
View File

@ -40,6 +40,9 @@
<I>trate</I> value = R
R = true strain rate (1/time units)
<I>volume</I> value = none = adjust this dim to preserve volume of system
<I>wiggle</I> value = A Tp
A = amplitude of oscillation (distance units)
Tp = period of oscillation (time units)
<I>xy</I>, <I>xz</I>, <I>yz</I> args = style value
style = <I>final</I> or <I>delta</I> or <I>vel</I> or <I>erate</I> or <I>trate</I>
<I>final</I> value = tilt
@ -52,7 +55,10 @@
<I>erate</I> value = R
R = engineering shear strain rate (1/time units)
<I>trate</I> value = R
R = true shear strain rate (1/time units)
R = true shear strain rate (1/time units)
<I>wiggle</I> value = A Tp
A = amplitude of oscillation (distance units)
Tp = period of oscillation (time units)
</PRE>
<LI>zero or more keyword/value pairs may be appended
@ -213,8 +219,20 @@ potentials whose Poisson ratio is not 0.5. An alternative is to use
<A HREF = "fix_npt.html">fix npt aniso</A> with zero applied pressure on those 2
dimensions, so that they respond to the tensile strain dynamically.
</P>
<P>For the <I>scale</I>, <I>vel</I>, <I>erate</I>, <I>trate</I>, and <I>volume</I> styles, the box
length is expanded or compressed around its mid point.
<P>The <I>wiggle</I> style oscillates the specified box length dimension
sinusoidally with the specified amplitude and period. I.e. the box
length L as a function of time is given by
</P>
<PRE>L(t) = L0 + A sin(2*pi t/Tp)
</PRE>
<P>where L0 is its initial length. If the amplitude A is a positive
number the box initially expands, then contracts, etc. If A is
negative then the box initially contracts, then expands, etc. The
amplitude can be in lattice or box distance units. See the discussion
of the units keyword below.
</P>
<P>For the <I>scale</I>, <I>vel</I>, <I>erate</I>, <I>trate</I>, <I>volume</I>, and <I>wiggle</I>
styles, the box length is expanded or compressed around its mid point.
</P>
<HR>
@ -293,6 +311,19 @@ tilt factor, but assume the perpendicular box length remains constant.
If this is not the case (e.g. it changes due to another fix deform
parameter), then this effect on the shear strain is ignored.
</P>
<P>The <I>wiggle</I> style oscillates the specified tilt factor sinusoidally
with the specified amplitude and period. I.e. the tilt factor Tf as a
function of time is given by
</P>
<PRE>Tf(t) = Tf0 + A sin(2*pi t/Tp)
</PRE>
<P>where Tf0 is its initial value. If the amplitude A is a positive
number the tilt factor initially becomes more positive, then more
negative, etc. If A is negative then the tilt factor initially
becomes more negative, then more positive, etc. The amplitude can be
in lattice or box distance units. See the discussion of the units
keyword below.
</P>
<P>All of these styles change the xy, xz, yz tilt factors during a
simulation. In LAMMPS, tilt factors (xy,xz,yz) for triclinic boxes
are always bounded by half the distance of the parallel box length.

37
doc/fix_deform.txt
View File

@ -33,6 +33,9 @@ parameter = {x} or {y} or {z} or {xy} or {xz} or {yz}
{trate} value = R
R = true strain rate (1/time units)
{volume} value = none = adjust this dim to preserve volume of system
{wiggle} value = A Tp
A = amplitude of oscillation (distance units)
Tp = period of oscillation (time units)
{xy}, {xz}, {yz} args = style value
style = {final} or {delta} or {vel} or {erate} or {trate}
{final} value = tilt
@ -45,7 +48,10 @@ parameter = {x} or {y} or {z} or {xy} or {xz} or {yz}
{erate} value = R
R = engineering shear strain rate (1/time units)
{trate} value = R
R = true shear strain rate (1/time units) :pre
R = true shear strain rate (1/time units)
{wiggle} value = A Tp
A = amplitude of oscillation (distance units)
Tp = period of oscillation (time units) :pre
zero or more keyword/value pairs may be appended :l
keyword = {remap} or {units} :l
@ -203,8 +209,20 @@ potentials whose Poisson ratio is not 0.5. An alternative is to use
"fix npt aniso"_fix_npt.html with zero applied pressure on those 2
dimensions, so that they respond to the tensile strain dynamically.
For the {scale}, {vel}, {erate}, {trate}, and {volume} styles, the box
length is expanded or compressed around its mid point.
The {wiggle} style oscillates the specified box length dimension
sinusoidally with the specified amplitude and period. I.e. the box
length L as a function of time is given by
L(t) = L0 + A sin(2*pi t/Tp) :pre
where L0 is its initial length. If the amplitude A is a positive
number the box initially expands, then contracts, etc. If A is
negative then the box initially contracts, then expands, etc. The
amplitude can be in lattice or box distance units. See the discussion
of the units keyword below.
For the {scale}, {vel}, {erate}, {trate}, {volume}, and {wiggle}
styles, the box length is expanded or compressed around its mid point.
:line
@ -283,6 +301,19 @@ tilt factor, but assume the perpendicular box length remains constant.
If this is not the case (e.g. it changes due to another fix deform
parameter), then this effect on the shear strain is ignored.
The {wiggle} style oscillates the specified tilt factor sinusoidally
with the specified amplitude and period. I.e. the tilt factor Tf as a
function of time is given by
Tf(t) = Tf0 + A sin(2*pi t/Tp) :pre
where Tf0 is its initial value. If the amplitude A is a positive
number the tilt factor initially becomes more positive, then more
negative, etc. If A is negative then the tilt factor initially
becomes more negative, then more positive, etc. The amplitude can be
in lattice or box distance units. See the discussion of the units
keyword below.
All of these styles change the xy, xz, yz tilt factors during a
simulation. In LAMMPS, tilt factors (xy,xz,yz) for triclinic boxes
are always bounded by half the distance of the parallel box length.