Dear LAMMPS users
I am trying to use LAMMPS for indentation analysis of copper by diamond indenter. I am using hybrid pair style, and fix move command to move a spherical rigid region as indenter.
The issue is the copper structure is fluctuating inconsistently. The forces are also inconsistent; the unloading forces are negative from starting.
I would appreciate some expert advice on following considerations.
- Using four atoms types 1-3 copper (for visualizing boundary w_mobile, w_thermostat, w_boundary) and 4 diamond
pair_style hybrid tersoff eam morse 2.5658
pair_coeff * * tersoff SiC.tersoff NULL NULL NULL C
pair_coeff 1*3 4 morse 0.087 5.14 2.05 9.025
pair_coeff 13 13 eam Cu_u3.eam
my intention is to apply tersoff for all interactions, then override Cu-C as morse and Cu-Cu as eam. So the remaining C-C will be tersoff.
- Creating velocity at 300K and applying nve ensemble
velocity w_mobile create 300.0 12345 temp tmobile
run 0
velocity w_mobile scale 300.0
fix 1 w_mobile nve
fix 2 w_thermostat nve
fix 3 all temp/rescale 1 300.0 300.0 0.1 1.0
fix 4 w_boundary setforce 0.0 0.0 0.0
fix 5 i_diamond rigid single
.
.
unfix 3
fix 3 w_thermostat temp/rescale 1 300 300 0.1 1.0
- Can a region be considered rigid if applying no fix on the region? Or should apply fix rigid.
Using fix rigid command causing atom lost error.
-
Is fix move command adequate for the indentation purpose?
-
Using
a. variable fz equal fcm(i_diamond,z) for force on indenter
b. variable depthz equal xcm(i_diamond,z) for position of indenter
I am using periodic boundary in x, y and non-periodic fixed boundary for z
· Version: LAMMPS 64-bit 16Mar2018
Regards
Mohit Sharma
Precision Manufacturing Lab
NTUST, Taipei Taiwan