Numerical evaluation of effective elastic properties of
graphite fiber tow impregnated by polymer matrix
by
J. Zeman and M. Sejnoha
Abstract
Homogenized elastic material properties are
found for a fibrous graphite-epoxy composite system with fibers
randomly distributed within a transverse plane section of the
composite aggregate using the finite element method. To
enhance efficiency of the numerical analysis the real microstructure
is replaced by a material representative volume element,
represented here by a periodic unit cell consisting of a small number
of particles, which statistically resembles the actual composite. Such
a unit cell is derived from a simple optimization procedure formulated
in terms of various statistical descriptors characterizing the
microstructure of the random medium. In the present approach the
two-point probability and the second order intensity functions are
employed. The upper bound on the macroscopic elastic stiffnesses
then follows from the principle of minimum potential energy.
The Finite Element Method (FEM) is called to carry out the
numerical analysis. Results derived herein confirm applicability
of the present approach and suggest that the unit cell,
which effectively exploits the knowledge of the material's statistics
of the composite, is more reliable then the one constructed simply
as a cut of a small part of the real microstructure.
Last modified: Nov 4 2000