Dear all,
I performed tensile deformations on the graphene sheet along zigzag direction using the fix deform command in a npt ensamble. The potential I used is AIREBO. Normally the stress should increase with the larger strain before the fracture point. In my case the stress-strain curve goes well before the fracture point suggest by previous papers (about 0.2 for zigzag deformation in a 10nm*10 nm graphene) but later the stress and the potential of the system go up steeply, and the sheet breaks at a strain about 0.4.
Why does the stress goes up when the strain is large? Could anyone give a suggestion? I have attached my input script and the result. Thank you in advance.
Best regards
Sincerely yours
shelleny
tensile.eps (69.4 KB)