What is the difference between tensile MD simulation and non-equilibrium MD simulation?

Hi,

Can anyone explain the difference between the following approaches?

  1. Using the “deform” option alone in an MD simulation vs. using “deform” in combination with other options (e.g., acc-grps, accelerate, etc.) in non-equilibrium MD (NEMD) simulations.

Which method is best for investigating the stress-strain behavior and stretchability of a polymer composite?

I have tried “deform” in combination with other options, but 'deform" option alone would provide a constant strain rate to the simulation box. If your polymer composite is an infinite molecule, the deform option alone would be an ideal method for investigating the stress-strain behavior.

Hi,

Thank you very much for your comment. What would you recommend if the polymer is viscoelastic?

I have seen lots of work on this being used regularly in viscoelastic polymers, where the box is pulled at a constant rate using “deform” option to compute these mechanical properties.

Hi again,

Thank you very much for your input. Unfortunately, for my polymer material, simple “deform” simulation MD simulation has failed to predict the Young’s modulus (I got 1000 times higher value than the experiment value). Therefore, I am looking for an alternative approach, where I can get reasonable value for the Young’s modulus.

Why don’t you just pull the material then, using pull code?

Instead of oscillatory shear MD simulation, why do you suggest pull code?