Hi Dear
I use Lammps to calculate elastic constants of vinylester/titan nanocomposites. I use following commands to calculate it:
fix tensile all deform 1 x scale 1.005 y volume z volume remap x
compute mystress all stress/atom
compute fx all reduce sum c_mystress[1]
thermo 10
thermo_style custom step temp c_fx[1] lx ly lz xy press vol
run 10
unfix tensile
But the results of c_fx[1] is very much, for example the value of it in step of 10000 is