Dumped value of normal force not matching with calculated normal force

Hi Anand,
Which contact law, and fix, are you using?
Could you post a test case with only two particles, displaying the behavior you describe?
If you're using fix deform remap x, it may be part of the problem.
Good luck,
Robin

Hi Anand,
I'm not using any hertzian law, so I never checked.
Here's an example of a test case for the tangential damping, which seems to work fine (error=machine epsilon).
You might want to do the same for the law you need, and post it, because we cannot do mush with only the result files.
Cheers,
Robin

### Simulation parameters
variable gamt equal 1e6
variable diam equal 1.5 # particle diameter
variable timeStep equal 0.01 # time step
variable mass equal 1e14 # particles mass
variable nStep equal 20 # number of steps

### General settings
atom_style granular
atom_modify map array
boundary f f f
newton off
communicate single vel yes
units si
neighbor $(v_diam/10) bin
neigh_modify delay 0
timestep ${timeStep}

### Domain definition, particles generation, velocity
region myRegion block -2 2 -2 2 -2 2 units box
create_box 1 myRegion
create_atoms 1 single 0 0 $(0.7*0.5*v_diam)
create_atoms 1 single 0 0 $(-.7*0.5*v_diam)
group 1 id 1 # for velocity command
group 2 id 2
set region myRegion diameter ${diam}
set region myRegion mass ${mass}
velocity 1 set 0 +1e+0 0
velocity 2 set 0 -1e+0 0

### Interaction model choice
fix myFric all property/global coefficientFriction peratomtypepair 1 1e300
fix myKn all property/global kn peratomtypepair 1 0
fix myKt all property/global kt peratomtypepair 1 0
fix myCn all property/global gamman_abs peratomtypepair 1 0
fix myCt all property/global gammat_abs peratomtypepair 1 ${gamt}
pair_style gran model hooke/stiffness tangential history absolute_damping on
pair_coeff * *

### Force verification
compute i all pair/gran/local vel force_tangential # Output: vx1 vy1 vz1 vx2 vy2 vz2 fTx fTy fTz
compute j all reduce max c_i[2] c_i[3] c_i[5] c_i[6] c_i[8] c_i[9] # Local variables can't be handled by command variable. Only one pair: take the max.
# Tangential force from liggghts
variable FtLig equal (c_j[5]^2+c_j[6]^2)^0.5
# Tangential velocity from liggghts
variable distY equal y[1]-y[2]
variable distZ equal z[1]-z[2]
variable r equal (v_distY^2+v_distZ^2)^0.5
variable enY equal v_distY/v_r
variable enZ equal v_distZ/v_r
variable veloY equal c_j[1]-c_j[3]
variable veloZ equal c_j[2]-c_j[4]
variable veloN equal v_veloY*v_enY+v_veloZ*v_enZ
variable veloNY equal v_veloN*v_enY
variable veloNZ equal v_veloN*v_enZ
variable veloTY equal v_veloY-v_veloNY
variable veloTZ equal v_veloZ-v_veloNZ
variable veloT equal (v_veloTY^2+v_veloTZ^2)^0.5
# Theoretical tangential force from velocity
variable Ft equal v_gamt*v_veloT
variable error equal (v_FtLig-v_Ft)/v_Ft

### Output
thermo_style custom step v_veloT v_FtLig v_Ft v_error # choose data to output
thermo_modify format float %e # set format to scientific notation

### Run
fix myIntegration all nve
run ${nStep}