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lammps/examples/USER/atc/cauchy_born/in.cb_shear
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in.cb_shear
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# This test compares Hardy and Cauchy-Born metrics of energy density and stress
# for an Ar system subjected to shear deformation.
#
# NOTE possible problems with large shear and handling a non-ortho box
echo both
units metal
atom_style atomic
variable lattice_constant equal 4.08
variable c equal 6 # minimum size
variable Ly equal $c*${lattice_constant}
variable d equal 0.005
variable V0 equal ($c*${lattice_constant})^3
# create system
lattice fcc ${lattice_constant} origin 0.25 0.25 0.25
# NOTE rect box + lagrangian is necessary to fool ATC's mesh
region rectbox block 0 $c 0 $c 0 3
region box prism 0 $c 0 $c 0 3 0 0 0
boundary p p p
create_box 1 box
create_atoms 1 region box
mass 1 196.97
group all region box
pair_style lj/smooth/linear 5.456108274435118
pair_coeff * * 0.7242785984051078 2.598146797350056
neighbor 1.0 bin
#neigh_modify delay 1000000
log cb_shear.log
thermo 100
variable gamma equal 0.0
variable step equal 0
thermo_style custom step v_step pxx pyy pzz pxy pxz pyz v_gamma pe xy xz yz
timestep 1.0
fix AtC all atc field Au_CauchyBorn.mat
fix_modify AtC mesh create $c $c 1 rectbox p p p
fix_modify AtC fields add mass_density internal_energy stress
fix_modify AtC fields add displacement
fix_modify AtC fields add cauchy_born_energy cauchy_born_stress
fix_modify AtC gradients add displacement
fix_modify AtC set reference_potential_energy 0.
#fix_modify AtC fields add elastic_deformation_gradient
fix_modify AtC output cb_shearFE 1 text binary tensor_components
min_modify line quadratic
variable dgamma equal $d/${Ly}
print "depsilon_12: ${dgamma}"
timestep 0.0
variable i loop 4
label loop_i
print ">>> step $i"
minimize 1.e-20 1.e-20 1000 1000
run 1
variable step equal ${step}+1
change_box all xy delta $d remap
variable gamma equal $i*${dgamma}
next i
jump in.cb_shear loop_i
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