  With increasing interest in the use of glassy carbon (GC) for a wide variety
of application areas, the need for developing fundamental understanding of its
mechanical properties has come to the forefront. Further, recent theoretical
and modeling works that shed some light on the synthesis of GC through the
process of pyrolysis of polymer precursors have highlighted the possibilities
of a revisit to investigation of its mechanical properties at a fundamental
level. While there are isolated reports on the experimental determination of
its elastic modulus, insights into stress-strain behavior of GC material under
tension and compression obtained through simulation, either at molecular level
or for the bulk material is missing. This current study fills the gap at the
molecular level and investigates the mechanical properties of GC using
molecular dynamics (MD) simulations which model the atomistic level formation
and breaking of bonds using bond-order based reactive force field formulations.
The molecular model considered for this simulation has a characteristics 3D
cagey structure of 5-, 6-, and 7-membered carbon rings and graphitic domain of
a flat graphene-like structure. The GC molecular model was subjected to loading
under varying strain rates (0.4/ns, 0.6/ns, 1.25/ns, and 2.5/ns) and varying
temperatures (300 - 800 K) in each of the three axes x, y, and z. The
simulation showed that GC molecule has distinct stress-strain curves under
tension and compression. In tension, MD modeling predicted mean elastic modulus
of 5.71 GPa for a single GC molecule with some dependency on strain rates and
temperature, while in compression, the elastic modulus was also found to depend
on the strain rates as well as temperature and was predicted to have a mean
value of 35 GPa
