hi everybody,
I am trying to simulate a top and a bottom mesh platen contained by rings. these rings are made by "fix rigid" command using small particles (dia. 0.0002 mm). rings are filled by particles (dia. 0.001 mm). so I use these commands (briefly) :
atom_style granular
boundary m m m
newton off
communicate single vel yes
units si
read_data .../NGIgrains ############reads particles proprties and position
neighbor 0.001 bin
neigh_modify delay 0 exclude type 2 2 exclude type 2 3 ##type 1 is for particles type 2 is for rigid body (rings) and type 3 is for platens
##############Material properties required for new pair styles
fix m1 all property/global youngsModulus peratomtype 4.e8 4.e8 4.e8
fix m2 all property/global poissonsRatio peratomtype 0.22 0.22 0.22
fix m3 all property/global coefficientFriction peratomtypepair 3 0.05 0.0 0.9 0.0 0.0 0.0 0.9 0.0 0.0
fix m4 all property/global coefficientRestitution peratomtypepair 3 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87
pair_style gran/hertz/history
pair_coeff * *
timestep 0.0000014
# walls
fix bottom all mesh/surface/stress file bottom.stl type 3
fix plate all mesh/surface/stress file plate.stl type 3
fix meshessprop all wall/gran/hertz/history mesh n_meshes 2 meshes bottom plate
################
#different groups are defined here
group particles type 1
group rings type 2
group r1 id <> 67099 71510 #########small particles based on their ids are assigned to different rings from 1 to 25
fix rigid rings rigid group 25 r1 ... #######rings are defined using fix rigid
group nveinteg type 1 3 ###########maybe here should be considered
fix integr nveinteg nve/sphere #######integration is just set for particles and mesh walls
fix f0rigid rings setforce 0.0 0.0 0.0 #######setting force and velocity to 0.0 to make rings stationary
velocity rings set 0.0 0.0 0.0 units box
run 1000
here are my questions
1-rings should not interact with mesh walls and should not impose any force on them. but after running the script it is obvious that it does not happen and the ring particles exert a constant force on mesh walls. what is the poblem?
2- should I consider these small particles used for rigid body as those dominating on the timestep?
any suggestion will be appriciated.
best regards
m.a.