I'm running a simulation to imitate a tensile test by using the following commands (My ensemble is NVT and I want a strain of 0.05 along z at the end of the simulation):
fix 1 all nvt 150.0 150.0 100.0
fix 2 all uniaxial 100 z 1.05
The stress values (that are calculated by lammps) fluctuate around a constant value and do not increase with increasing strain. I also calculated stress components that lammps do not include in its calculation (intra-molecular interactions such as bond, angle and dihedral potentials) and they also fluctuate around a constant value.
Is it wrong to use fix/nvt with fix/uniaxial in the way that I'm using?
Also, in order to calculate the total stress, is it ok to add stresses of individual atoms along a certain direction (i.e., sxx, syy, szz etc.) for a saved configuration?
Thank you for your help,