Strain calculations in LAMMPS

Dear All
I have layered structure made of Materials “1” and “2” with their corresponding lattice parameters “a1” and “a2”. My aim is to calculate the strain distribution inside the layered system ( color-coded image ) by means of equation (14) and (15) from from this article: Ken-ichi Saitoh, Wing Kam Liu “Molecular dynamics study of surface effect on martensitic cubic-to-tetragonal transformation in Ni–Al alloy”, Computational Materials Science 46 (2009) 531–544. My difficulty is, how to write equations (14) and (15) in LAMMPS script?


saitoh2009.pdf (3.16 MB)

Those formulas are a sum over pairwise quantities, so there is no

way to encode the formula in the input script, e.g. as a variable formula.
I think you’d have to post-process the formulas from dump files, or
write your own compute to use a neighbor list and calculate the values
on-the-fly. You could look at compute displace/atom and compute stress/atom
to see similar operations.