Unverified Commit 8d9697db authored by Axel Kohlmeyer's avatar Axel Kohlmeyer Committed by GitHub
Browse files

Merge pull request #1420 from dsbolin/gran_mods 

Updates and bugfixes to GRANULAR package
parents f0525090 98daf8f8

doc/src/fix_wall_gran.txt

+11 −11
Original line number Diff line number Diff line
@@ -47,9 +47,9 @@ keyword = {wiggle} or {shear} :l 
fix 1 all wall/gran hooke  200000.0 NULL 50.0 NULL 0.5 0 xplane -10.0 10.0

fix 1 all wall/gran hooke/history 200000.0 NULL 50.0 NULL 0.5 0 zplane 0.0 NULL

fix 2 all wall/gran hooke 100000.0 20000.0 50.0 30.0 0.5 1 zcylinder 15.0 wiggle z 3.0 2.0

fix 3 all wall/gran granular hooke 1000.0 50.0 tangential linear_nohistory 1.0 0.4 zplane 0.0 NULL

fix 4 all wall/gran granular jkr 1000.0 50.0 0.3 5.0 tangential mindlin 800.0 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall zcylinder 15.0 wiggle z 3.0 2.0

fix 5 all wall/gran granular dmt 1000.0 50.0 0.3 10.0 tangential mindlin 800.0 0.5 0.1 roll sds 500.0 200.0 0.1 twisting marshall zplane 0.0 NULL :pre

fix 3 all wall/gran/region granular hooke 1000.0 50.0 tangential linear_nohistory 1.0 0.4 damping velocity region myBox

fix 4 all wall/gran/region granular jkr 1e5 1500.0 0.3 10.0 tangential mindlin NULL 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall region myCone

fix 5 all wall/gran/region granular dmt 1e5 0.2 0.3 10.0 tangential mindlin NULL 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall damping tsuji region myCone :pre



[Description:]

doc/src/fix_wall_gran_region.txt

+11 −11
Original line number Diff line number Diff line
@@ -31,9 +31,9 @@ region-ID = region whose boundary will act as wall :l,ule 
[Examples:]



fix wall all wall/gran/region hooke/history 1000.0 200.0 200.0 100.0 0.5 1 region myCone

fix 3 all wall/gran/region granular hooke 1000.0 50.0 tangential linear_nohistory 1.0 0.4 region myBox

fix 4 all wall/gran/region granular jkr 1000.0 50.0 tangential linear_history 800.0 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall region myCone

fix 5 all wall/gran/region granular dmt 1000.0 50.0 0.3 10.0 tangential linear_history 800.0 0.5 0.1 roll sds 500.0 200.0 0.1 twisting marshall region myCone :pre

fix 3 all wall/gran/region granular hooke 1000.0 50.0 tangential linear_nohistory 1.0 0.4 damping velocity region myBox

fix 4 all wall/gran/region granular jkr 1e5 1500.0 0.3 10.0 tangential mindlin NULL 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall region myCone

fix 5 all wall/gran/region granular dmt 1e5 0.2 0.3 10.0 tangential mindlin NULL 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall damping tsuji region myCone :pre



[Description:]

doc/src/pair_granular.txt

+53 −25
Original line number Diff line number Diff line
@@ -24,22 +24,24 @@ cutoff = global cutoff (optional). See discussion below. :ul 
[Examples:]



pair_style granular

pair_coeff * * hooke 1000.0 50.0 tangential linear_nohistory 1.0 0.4 :pre

pair_coeff * * hooke 1000.0 50.0 tangential linear_nohistory 1.0 0.4 damping mass_velocity :pre



pair_style granular

pair_coeff * * hertz 1000.0 50.0 tangential mindlin NULL 1.0 0.4 :pre

pair_coeff * * hooke 1000.0 50.0 tangential linear_history 500.0 1.0 0.4 damping mass_velocity :pre



pair_style granular

pair_coeff * * hertz/material 1e8 0.3 tangential mindlin_rescale NULL 1.0 0.4 damping tsuji :pre

pair_coeff * * hertz 1000.0 50.0 tangential mindlin 1000.0 1.0 0.4 :pre



pair_style granular

pair_coeff 1 1 jkr 1000.0 50.0 tangential mindlin 800.0 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall

pair_coeff 2 2 hertz 200.0 20.0 tangential linear_history 300.0 1.0 0.1 rolling sds 200.0 100.0 0.1 twisting marshall :pre

pair_coeff * * hertz/material 1e8 0.3 0.3 tangential mindlin_rescale NULL 1.0 0.4 damping tsuji :pre



pair_style granular

pair_coeff 1 1 hertz 1000.0 50.0 tangential mindlin 800.0 0.5 0.5 rolling sds 500.0 200.0 0.5 twisting marshall

pair_coeff 2 2 dmt 1000.0 50.0 0.3 10.0 tangential mindlin 800.0 0.5 0.1 roll sds 500.0 200.0 0.1 twisting marshall

pair_coeff 1 2 dmt 1000.0 50.0 0.3 10.0 tangential mindlin 800.0 0.5 0.1 roll sds 500.0 200.0 0.1 twisting marshall :pre

pair_coeff 1 * jkr 1000.0 500.0 0.3 10 tangential mindlin 800.0 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall

pair_coeff 2 2 hertz 200.0 100.0 tangential linear_history 300.0 1.0 0.1 rolling sds 200.0 100.0 0.1 twisting marshall :pre



pair_style granular

pair_coeff 1 1 dmt 1000.0 50.0 0.3 0.0 tangential mindlin NULL 0.5 0.5 rolling sds 500.0 200.0 0.5 twisting marshall

pair_coeff 2 2 dmt 1000.0 50.0 0.3 10.0 tangential mindlin NULL 0.5 0.1 rolling sds 500.0 200.0 0.1 twisting marshall :pre



[Description:]
@@ -57,18 +59,18 @@ global, but can be set to different values for different combinations 
of particle types, as determined by the "pair_coeff"_pair_coeff.html

command.  If the contact model choice is the same for two particle

types, the mixing for the cross-coefficients can be carried out

automatically. This is shown in the second example, where model

automatically. This is shown in the last example, where model

choices are the same for type 1 - type 1 as for type 2 - type2

interactions, but coefficients are different. In this case, the

coefficients for type 2 - type interactions can be determined from

mixed coefficients for type 1 - type 2 interactions can be determined from

mixing rules discussed below.  For additional flexibility,

coefficients as well as model forms can vary between particle types,

as shown in the third example: type 1- type 1 interactions are based

on a Hertzian normal contact model and 2-2 interactions are based on a

DMT cohesive model (see below).  In that example, 1-1 and 2-2

interactions have different model forms, in which case mixing of

as shown in the fourth example: type 1 - type 1 interactions are based

on a Johnson-Kendall-Roberts normal contact model and 2-2 interactions

are based on a DMT cohesive model (see below).  In that example, 1-1

and 2-2 interactions have different model forms, in which case mixing of

coefficients cannot be determined, so 1-2 interactions must be

explicitly defined via the {pair_coeff 1 2} command, otherwise an

explicitly defined via the {pair_coeff 1 *} command, otherwise an

error would result.



:line
@@ -189,6 +191,7 @@ other settings, potentially also the twisting damping). The options 
for the damping model currently supported are:



{velocity}

{mass_velocity}

{viscoelastic}

{tsuji} :ol
@@ -199,11 +202,23 @@ For {damping velocity}, the normal damping is simply equal to the 
user-specified damping coefficient in the {normal} model:



\begin\{equation\}

\eta_n = \eta_\{n0\}\

\eta_n = \eta_\{n0\}

\end\{equation\}



Here, \(\eta_\{n0\}\) is the damping coefficient specified for the normal

contact model, in units of {mass}/{time}.



For {damping mass_velocity}, the normal damping is given by:



\begin\{equation\}

\eta_n = \eta_\{n0\} m_\{eff\}

\end\{equation\}



Here, \(\gamma_n\) is the damping coefficient specified for the normal

contact model, in units of {mass}/{time},

Here, \(\eta_\{n0\}\) is the damping coefficient specified for the normal

contact model, in units of {mass}/{time} and

\(m_\{eff\} = m_i m_j/(m_i + m_j)\) is the effective mass.

Use {damping mass_velocity} to reproduce the damping behavior of

{pair gran/hooke/*}.



The {damping viscoelastic} model is based on the viscoelastic

treatment of "(Brilliantov et al)"_#Brill1996, where the normal
@@ -213,11 +228,10 @@ damping is given by: 
\eta_n = \eta_\{n0\}\ a m_\{eff\}

\end\{equation\}



Here, \(m_\{eff\} = m_i m_j/(m_i + m_j)\) is the effective mass, {a}

is the contact radius, given by \(a =\sqrt\{R\delta\}\) for all models

except {jkr}, for which it is given implicitly according to \(delta =

a^2/R - 2\sqrt\{\pi \gamma a/E\}\).  In this case, \eta_\{n0\}\ is in

units of 1/({time}*{distance}).

Here, {a} is the contact radius, given by \(a =\sqrt\{R\delta\}\)

for all models except {jkr}, for which it is given implicitly according

to \(\delta = a^2/R - 2\sqrt\{\pi \gamma a/E\}\).  For {damping viscoelastic},

\(\eta_\{n0\}\) is in units of 1/({time}*{distance}).



The {tsuji} model is based on the work of "(Tsuji et

al)"_#Tsuji1992. Here, the damping coefficient specified as part of
@@ -564,6 +578,20 @@ Finally, the twisting torque on each particle is given by: 


:line



The {granular} pair style can reproduce the behavior of the

{pair gran/*} styles with the appropriate settings (some very

minor differences can be expected due to corrections in

displacement history frame-of-reference, and the application

of the torque at the center of the contact rather than

at each particle). The first example above

is equivalent to {pair gran/hooke 1000.0 NULL 50.0 50.0 0.4 1}.

The second example is equivalent to

{pair gran/hooke/history 1000.0 500.0 50.0 50.0 0.4 1}.

The third example is equivalent to

{pair gran/hertz/history 1000.0 500.0 50.0 50.0 0.4 1}.



:line



LAMMPS automatically sets pairwise cutoff values for {pair_style

granular} based on particle radii (and in the case of {jkr} pull-off

distances). In the vast majority of situations, this is adequate.
@@ -619,7 +647,7 @@ interactions is set to \(\mu_1\), and friction coefficient for type 
2-type 2 interactions is set to \(\mu_2\), the friction coefficient

for type1-type2 interactions is computed as \(\sqrt\{\mu_1\mu_2\}\)

(unless explicitly specified to a different value by a {pair_coeff 1 2

...} command. The exception to this is elastic modulus, only

...} command). The exception to this is elastic modulus, only

applicable to {hertz/material}, {dmt} and {jkr} normal contact

models. In that case, the effective elastic modulus is computed as:

examples/granular/in.pour.drum

0 → 100644
+98 −0
Original line number Diff line number Diff line 
# pour two types of particles (cohesive and non-cohesive) into cylinder

# 'turn' cylinder by changing direction of gravity, then rotate it.

# This simulates a rotating drum powder characterization experiment.



variable	name string rotating_drum_two_types



atom_style	sphere

units		lj



###############################################

# Geometry-related parameters

###############################################



variable	boxx equal 30

variable	boxy equal 30

variable	boxz equal 50



variable	drum_rad equal ${boxx}*0.5

variable	drum_height equal 20



variable	xc equal 0.5*${boxx}

variable	yc equal 0.5*${boxx}

variable	zc equal 0.5*${boxz}



###############################################

# Particle-related parameters

###############################################

variable	rlo equal 0.25

variable	rhi equal 0.5

variable	dlo equal 2.0*${rlo}

variable	dhi equal 2.0*${rhi}



variable	cyl_rad_inner equal ${drum_rad}-1.1*${rhi}



variable	dens equal 1.0



variable skin equal 0.4*${rhi}



#############

processors * * 1

region		boxreg block 0 ${boxx} 0 ${boxy} 0 ${boxz}

create_box	2 boxreg

change_box	all boundary p p f

comm_modify	vel yes



variable	theta equal 0



region		curved_wall cylinder z ${xc} ${yc} ${drum_rad} 0 ${drum_height} side in rotate v_theta ${xc} ${yc} 0 0 0 1

region		bottom_wall plane ${xc} ${yc} 0 0 0 1 side in rotate v_theta ${xc} ${yc} 0 0 0 1



region		insreg cylinder z ${xc} ${yc} ${cyl_rad_inner} ${drum_height} ${boxz}



fix		0 all balance 100 1.0 shift xy 5 1.1

fix		1 all nve/sphere

fix		grav all gravity 10 vector 0 0 -1

fix		ins1 all pour 2000 1 1234 region insreg diam range ${dlo} ${dhi} dens ${dens} ${dens}

fix		ins2 all pour 2000 2 1234 region insreg diam range ${dlo} ${dhi} dens ${dens} ${dens}



comm_modify	vel yes



neighbor	${skin} bin

neigh_modify	delay 0 every 1 check yes



pair_style	granular 

pair_coeff	1 * hertz/material 1e5 0.2 0.3 tangential mindlin NULL 1.0 0.5 damping tsuji

pair_coeff	2 2 jkr 1e5 0.1 0.3 50 tangential mindlin NULL 1.0 0.5 rolling sds 1e3 1e3 0.1 twisting marshall damping tsuji



fix		3 all wall/gran/region granular hertz/material 1e5 0.1 0.3 tangential mindlin NULL 1.0 0.5 damping tsuji region curved_wall 

fix		4 all wall/gran/region granular hertz/material 1e5 0.1 0.3 tangential mindlin NULL 1.0 0.5 damping tsuji region bottom_wall



thermo_style	custom step atoms ke v_theta

thermo_modify	lost warn

thermo		100



timestep	0.001



#dump		1 all custom 100 ${name}.dump id type radius mass x y z 



#For removal later

compute		1 all property/atom radius

variable	zmax atom z+c_1>0.5*${drum_height}

group		delgroup dynamic all var zmax every 10000



run		2000



#Remove any particles that are above z > 0.5*drum_height

delete_atoms	group delgroup



#Add top lid

region		top_wall plane ${xc} ${yc} ${drum_height} 0 0 -1 side in rotate v_theta ${xc} ${yc} 0 0 0 1

fix		5 all wall/gran/region granular hertz/material 1e5 0.1 0.3 tangential mindlin NULL 1.0 0.5 damping tsuji region top_wall



# 'Turn' drum by switching the direction of gravity

unfix		grav

fix		grav all gravity 10 vector 0 -1 0



variable	theta equal 2*PI*elapsed/20000.0

run		3000

examples/granular/in.pour.flatwall

0 → 100644
+67 −0
Original line number Diff line number Diff line 
# pour two types of particles (cohesive and non-cohesive) on flat wall



variable   	name string pour_two_types



atom_style	sphere

units		lj



###############################################

# Geometry-related parameters

###############################################



variable	boxx equal 20

variable	boxy equal 20

variable	boxz equal 30



variable	xc1 equal 0.3*${boxx}

variable	xc2 equal 0.7*${boxx}

variable	yc equal 0.5*${boxy}



###############################################

# Particle-related parameters

###############################################

variable	rlo equal 0.25

variable	rhi equal 0.5

variable	dlo equal 2.0*${rlo}

variable	dhi equal 2.0*${rhi}



variable	dens equal 1.0



variable skin equal 0.3*${rhi}



#############

processors	* * 1

region 		boxreg block 0 ${boxx} 0 ${boxy} 0 ${boxz}

create_box	2 boxreg

change_box	all boundary p p f



comm_modify 	vel yes



region		insreg1 cylinder z ${xc1} ${yc} 5 15 ${boxz}

region		insreg2 cylinder z ${xc2} ${yc} 5 15 ${boxz}



fix		1 all nve/sphere

fix		grav all gravity 10.0 vector 0 0 -1

fix		ins1 all pour 1500 1 3123 region insreg1 diam range ${dlo} ${dhi} dens ${dens} ${dens}

fix		ins2 all pour 1500 2 3123 region insreg2 diam range ${dlo} ${dhi} dens ${dens} ${dens}



comm_modify	vel yes



neighbor	${skin} bin

neigh_modify	delay 0 every 1 check yes



pair_style	granular 

pair_coeff 	1 * jkr 1000.0 50.0 0.3 10 tangential mindlin 800.0 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall

pair_coeff 	2 2 hertz 200.0 20.0 tangential linear_history 300.0 1.0 0.1 rolling sds 200.0 100.0 0.1 twisting marshall 



fix		3 all wall/gran granular hertz/material 1e5 1e3 0.3 tangential mindlin NULL 1.0 0.5 zplane 0 NULL 



thermo_style	custom step cpu atoms ke

thermo_modify	lost warn

thermo		100



timestep	0.001



#dump		1 all custom 100 ${name}.dump id type radius mass x y z 



run		5000

CRA Git | Maintained and supported by SUSTech CRA and CCSE