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86 30 Fibre Reinforced Polymer Composites
Tan et al. (1997b) proposed a 3D modelling technique for predicting the linear elastic
property of open-packed woven fabrics. Consider the unit cell of an open-packed plain
weave as shown in Figure 4.6, introduced is a simplified model as depicted in Figure
4.1 1. It is clear that the yarn undulation is approximated by a linear inclination. The
unit cell is divided into 9 regions which can be represented by the three micro-blocks
shown in Figure 4.11(b). Average material properties for each micro bIock are
evaluated first, and then the overall effective properties for the unit cell of the composite
are calculated by assembling micro-blocks in the warp direction first into stripes and
then in the weft direction or vice versa.
X I A-A A D-D
_.
Y
--f
B-B
A
a a
a-SCPMIB b-UMIB C-PRMIB
b'-UMIB after rotating 90" about z axis
(a) Unit cell
"A
X
' resin
Pure
Weft
Weft
(b) Micro-blocks
Figure 4.11 Simplified models for a unit cell of a plain woven composite (Tan et al,
1997b)
For the micro-block SCPMIB shown in Figure 4.1 l(b), the individual terms in equation
(4.6) are given by:
