Verifying experimental test results via LIGGGHTS

Hi Christoph,

I control the strain rate by moving my topwall, which is at the position of the particle with the highest z-coordinate (z0). If the z-coordinate of the highest particle reaches a certain value (z0-0.0125*z0 where 0.0125 is the 1.25% strain to be achieved and z0 the initial height of the top particle), the fix_move command will be unfixed.

I also changed my youngsModulus during simulation which I'm not quite sure if it worked at all. I had to start my Simulation with a lower YoungsModulus (90.e7), elsewise I wasn't able to reach a specific packing factor. After reaching this packingfactor I increased slowly the youngsmodulus to 90.e9 by using this code:

fix m1 all property/global youngsModulus peratomtype 90.e7 90.e7
.
.
.
->Packingfactor achieved

unfix m1
variable a loop 10
label loop
variable b equal $a*90.e7*10

print current YoungsModulus = ${b}
fix m1 all property/global youngsModulus peratomtype ${b} ${b}
run 100
unfix m1
next a
jump in.${NAME} loop

fix m1 all property/global youngsModulus peratomtype 90.e9 90.e9

I'm not sure if the Youngsmodulus was changed internally or if LIGGGHTS continues simulating with youngsmodulus=90.e7 (which would explain my wrong results)

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For the compressing part, my input script looks like this:

variable z_dehn equal "v_z0 - 0.0125 * v_z0"

fix press all move/mesh/gran linear 0 0 -0.01 units box deckel 1

fix out all print 100 "$t,${f_deckel_z},${hoehe_abs},${Packingfactor}" append post_${NAME}/dump/verdichten.csv screen no title "t,f_deckel_z,hoehe_abs,Packungsdichte"

label compress

undump I_stl
undump dmp

variable dump equal 1000
thermo ${dump}

dump I_stl all mesh/gran/VTK ${dump} post_${NAME}/dump/Zylinder-*.vtk stress stresscomponents
dump dmp all custom ${dump} post_${NAME}/dump/settle.* id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius

variable zmax equal bound(all,zmax)

variable f_zylinder_z equal f_zylinder[3]
variable f_deckel_z equal f_deckel[3]
variable hoehe_abs equal "v_zmax"

run 100

variable z_max_radius equal "v_zmax + v_Partikelradius"

if ${z_max_radius} > ${z_dehn} then "jump in.${NAME} compress"

unfix press