Molecular Dynamics Study on Stress-Strain in Very Thin Film : Size and Location of Region for Defining Stress and Strain

The stress and strain in a very thin film under uniaxial tension are analyzed based on the motion of particles in the film by means of two-dimensional molecular dynamics (MD) simulation. The Lennard-Jones(L-J) potential is assumed as a two-body potential. The tensile load is applied by elongating the fundamental cell longitudinally. The numerical results show that the stress decreases considerably as the size of the region for defining the stress decreases. It is found that more than 130 particles are necessary in the region for the stress concept to be applicable in continuum mechanics.