Title: Modeling functionally graded interphase regions in carbon nanotube reinforced
composites

Authors:
G. D. Seidel 1 gary-don@tamu.edu 979-845-0729
D.C. Lagoudas1 dlagoudas@aero.tamu.edu 979-845-1604
S.J.V. Frankland 2 sjvf@nianet.org
T.S. Gates 3 t.s.gates@larc.nasa.gov

1. Department of Aerospace Engineering, Texas A&M University, College Station,
TX 77843-3141
2. National Institute of Aerospace, 100 Exploration Way, Hampton, VA 23666-1399
3. NASA Langley Research Center, Mechanics of Structures and Materials Branch,
Hampton, VA 23681

ABSTRACT
A combination of micromechanics methods and molecular dynamics simulations
are used to obtain the effective properties of the carbon nanotube reinforced
composites with functionally graded interphase regions. The multilayer composite
cylinders method accounts for the effects of non-perfect load transfer in carbon
nanotube reinforced polymer matrix composites using a piecewise functionally graded
interphase. The functional form of the properties in the interphase region, as well as
the interphase thickness, is derived from molecular dynamics simulations of carbon
nanotubes in a polymer matrix. Results indicate that the functional form of the
interphase can have a significant effect on all the effective elastic constants except for
the effective axial modulus for which no noticeable effects are evident.