We generally do not respond to LAMMPs queries unless they are posted to
the mailing list (Cc'd on this reply). Also, I do not open attachments
unless I have some expectation that they are legitimate. There are myriad
incorrect ways to perform a stress-strain simulation, and only a few
correct ways. I suggest you start by reproducing a known simulation
result, and once you have achieved that, proceed to the system you are
really interested in.