As a part of this calculation I was using
fix 1 all npt temp 300 300 1 y 0 0 1 z 0 0 1 drag 1
For the value of P_start and P_final as "Zero", I'm observing no fracture in the sample even after a tensile strain of 250%!!!
But once I make those values as non-zero, e.g., 0.01, the same sample breaks/fractures at around a strain of ~40-45%.
Could anybody please enlighten this issue.