Fluctuations in Stress vs Strain graph

Hello lammps users
I am simulating BN using lammps. I am trying to draw stress vs strain graph using pressure in the direction of applied load as stress. But in the final part of the graph has very small fluctuations in pressure. So instead getting a smooth curve I get spread line with considerable thickness. Any suggestion to improve this? I am attaching a picture for the same… Please advise.



stress vs strain.png

Fluctuations are normal especially near

the failure point. You can try straining more slowly

or using a bigger system.