Computing Shear Strain and stress

Dear Users,
I apply a shear deformation via the command:
variable srate equal 1.0e10
variable srate1 equal "v_srate / 1.0e12"
fix 4 all deform 1 xy erate ${srate1} units box remap x
and now I want to compute the shear strain and shear stress so that I can draw the shear stress-strain curve. But when I don't know how to compute the shear strain and stress. The manual says that the shear strain = offset/length. well I understand that the length is the initial box length in y direction in my case. but I don't know how to compute the offset value. and what about the shear stress? can I compute it by -Pxy/10000 (GPa)?
Melika Vokhshoori

Hello Melika,

Offset is the tiltfactor-initial tilt factor for the simulation box in the direction you are shearing. So, in your case it will be like: (xy-xy0)/ly.

You can calculate the shear stress like you said but remember that is in P*V format. So, I would divide the value by the volume occupied by the system to get the shear stress.