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[lammps-users] 2D graphene simulation
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[lammps-users] 2D graphene simulation


From: Matthew Anthony Xuereb <matthew.a.xuereb.15@...7179...>
Date: Thu, 19 Oct 2017 09:03:22 +0200

Hi,

I am trying to simulate tensile stretching of a small graphene sheet (1000 atoms) with some dislocations generated in it. Current box size is 50 x 50 x 50 Angstroms which is enough to encompass all the atoms. Is there any way to stop the sheet from moving too much in the z-axis? I have tried many boundary styles, namely s and m, and the box always grows 10 times as large during the fix npt run i perform on the box. I do not want to restrict the sheet to a 2D simulation as this will not allow the sheet to ripple during equilibration (which i expect it to do due to the defect). I suspect that the neighbour and neigh_modify commands are the problem.

Below is part of the input file giving me these erroneous results;
 
units 		metal
dimension	3 
boundary	p	p   s  	
atom_style	charge

# ----------------------- ATOM DEFINITION ----------------------------
read_data defect.data
 
# ------------------------ FORCE FIELDS ------------------------------
pair_style	airebo 2.0 1 0
pair_coeff	* * CH.airebo C 

# ------------------------- SETTINGS ---------------------------------
neighbor 0.5 nsq  
neigh_modify every 5 delay 10 check yes    
    
######################################
# EQUILIBRATION
reset_timestep	0
timestep 0.001
fix 3 all box/relax vmax 0.0001 fixedpoint 0 0 0 
velocity all create 300 12345 mom yes rot no
fix 1 all npt temp 300 300 0.5 x 0 0 0.5 y 0 0 0.5 drag 1 

Thanks,

Matthew