Dear lammps users,
I’m trying to do a shear simulation by using the following model. There are two kinds of shear stress: (1) applied on the top layer (2) applied in xy direciton by fix defrom. The shear part of input file show below:
reset_timestep 0
boundary p p m
change_box all triclinic
variable zmax_work equal bound(workspace,zmax)
variable zmin_work equal bound(workspace,zmin)
velocity fixdow set 0.0 0.0 0.0 units box
fix 1 fixup setforce 0.0 0.0 0.0
fix 2 fixdow setforce 0.0 0.0 0.0
fix 3 all nvt temp Temperature Temperature 100.0*dt
fix 4 all deform 1 xy erate 0.0005 remap x units box (##### shear 2)
velocity fixup set 0.0 0.045 0.0 units box (##### shear 1)
velocity workspace ramp vy 0.0 0.045 z zmin_work zmax_work sum yes units box
compute 1 workspace stress/atom NULL
compute px workspace reduce ave c_1[1]
compute py workspace reduce ave c_1[2]
variable pxx equal c_px*1e-4/11.6393
variable pyy equal c_py*1e-4/11.6393
variable apxx atom c_1[1]*1e-4/11.6393
variable apyy atom c_1[2]*1e-4/11.6393
I am not sure the applied shear stress 1 and 2 is right or not according to the model. Is there high stress concentration in the region between worksapce and fixed layer? Thanks so much.