Cutoff for tensile simulation

Hello lammps users,
The tensile stress and strain mainly depend on the bond breaking distance. As per my observation from the couple of simulations of Carbon nano-tube with Tersoff and Airebo potential. I am encountering the Strain hardening problem. Its the significance of ductile material.
It purely because of Inner and Outer cutoff.

When i make inner and outer cutoff values identical its making smooth function values to 1 which is used in both Tersoff and Airebo. so because of that i am able avoid the strain hardening problem.

I have a question here whether my approach is make some sense? Please correct me if i am wrong.

I have attached four figures

fig 1: Stress Vs Strain for CNT with Airebo Rcmin_cc=1.7 and Rcmax_cc=2.0 (Default lammps potential values)
fig 2: Stress Vs Strain for CNT with Tersoff Rcmin_cc=1.8 and Rcmax_cc=2.1 (Default lammps potential values)
fig 3: Stress Vs Strain for CNT with Airebo Rcmin_cc=2.0 and Rcmax_cc=2.0
fig 4: PE Vs r for two carbon atoms with Airebo Rcmin_cc=2.0 and Rcmax_cc=2.0

fig 1.jpg

fig 2.jpg

fig 3.jpg

fig 4.jpg

Hello lammps users,
          The tensile stress and strain mainly depend on the bond breaking
distance. As per my observation from the couple of simulations of Carbon
nano-tube with Tersoff and Airebo potential. I am encountering the Strain
hardening problem. Its the significance of ductile material.
It purely because of Inner and Outer cutoff.

When i make inner and outer cutoff values identical its making smooth
function values to 1 which is used in both Tersoff and Airebo. so because
of that i am able avoid the strain hardening problem.

*I have a question here whether my approach is make some sense? Please
correct me if i am wrong. *

Absolutely not at all. You can't change a potential's cutoff and you
certainly can't make them the same, otherwise your potential energy surface
would have a major discontinuity.

Ray