Stress Strain curve of a brittle material

Dear Lammps users,

Hi,

I’m working on a simulation on uniaxial tensile stress test of a brittle material whose initial lattice structure is monoclinic. I did the test on z direction and my boundary condition was S S P. Moreover, I define a block region using my initial triclinic lattice structure. So, after minimization and equilibration, I did the test and finally draw its stress - strain curve. However, the things that is really surprising is that I get 20% for fracture strain. However, based on literature I know that it should be around 5%. So, I wonder you can comment on it and help me to get a better result. By the way, I’m attaching the stress - strain curve figure here.

Best,

Ali

Cubic.PNG

If you cannot reproduce the literature it is really up to you to find out what is different between your simulation setup and the literature. Unfortunately, it could be a lot of things: different force field, different boundary conditions, different method of applying strain, etc. If all of those are the same, then it must be that your implementation is wrong. Maybe some stress/strain experts can be of more specific help. In the meantime, it helps if you upload your input scripts.

Dear Lammps users,

Hi,

I'm working on a simulation on uniaxial tensile stress test of a brittle
material whose initial lattice structure is monoclinic. I did the test on z
direction and my boundary condition was S S P. Moreover, I define a *block
region* using my initial triclinic lattice structure. So, after
minimization and equilibration, I did the test and finally draw its stress
- strain curve. However, the things that is really surprising is that I get
20% for fracture strain. However, based on literature I know that it should
be around 5%. So, I wonder you can comment on it and help me to get a
better result. By the way, I'm attaching the stress - strain curve figure
here.

​there is not enough information here to make any suggestions.
apart from that, you are not really asking about LAMMPS, but how to do your
research properly. this is considered off-topic for this list. we prefer to
focus on discussing LAMMPS issues.
so what you are asking is a discussion that you should have with your
adviser/supervisor and/or more experienced colleagues.​

​axel.​

5% strain in literature. Is it simulation and expt. strain?