Table 2-3. Material properties of fibers used in the verification problem.
E-Glass Fiber Graphite Fiber (IM7)
El (GPa) 72.4 263
E2, E3 (GPa) 72.4 19
G12, G13 (GPa) 30.2 27.6
G23 (GPa) 30.2 27.6
v12, V13 0.2 0.2
V23 0.2 0.35
an (106/Co) 5.0 -0.9
a22, a33(10 6/Co) 5.0 7.2
Tensile strength (MPa) 1,104 1,725
The transversely isotropic properties of the glass and graphite fibers used in this
study are shown in Table 2-3 [26-27]. The material properties of fiber are assumed to be
independent to temperature changes.
Estimation of Thermo-Elastic Constants
The properties of a composite material depend on the constituent properties and
the microstructure of fiber and matrix layout and can be estimated by experimental
analysis and theoretical solutions. The experimental analysis is simple and trustworthy
but time consuming and expensive. Since the results are variable to fiber volume fraction,
constituent properties and fabrication process, the experimental analysis is required to
repeat the testing procedures. The theoretical and semi-empirical methods can be
effective when the composite material involves many variables which can affect
composite properties. However, the methods may not be reliable for component design
purpose and present difficulty in selecting a representative but tractable mathematical
model for some cases such as the transverse properties of some of the unidirectional
composites [26]. The mathematical solutions are unavailable as a simple form to predict
the transverse properties such as shear moduli G23 and Possion's ratio v23 [26]. In this