handbook of carbon, graphite, diamond and fullerenes

202 Carbon, Graphite, Diamond, and Fullerenes
usually low-strength and low-cost fibers in the form of felt or mat, with
applications in special types of carbon-carbon and in high-temperature
insulation (see Sees. 4.0 and 7.1 below).
2.4 Continuous Filaments
Most carbon fibers are in the form of continuous filaments with a
diameter averaging 10 ^m. They are applied unidirectionally (0°) by the
processing techniques of filament winding and tape layup described in Ref.
2. Such unidirectional systems have the highest property-translation
efficiency, i.e., the fraction of fiber properties translated into the composite.
On the other hand, they have low interlaminate strength because of the lack
of fibers in the thickness direction.
2.5 Laminar (2D Weaves)
Woven carbon fibers are usually biaxial structures, woven at 0° and 90°
(warp and fill) in three basic patterns: plain, satin, and twill. The highest
frequency ofyarn interlacing isfound in the plain weave, followed by the twill
and the satin weave. In the satin weave, the warp ends are woven over four
fill yarns and under one (five-harness satin) or over seven and under one
(eight-harness satin). The property translation efficiency is the highest in
satin weave, followed by twill and plain weave. Fig. 9.2 shows the plain and
twill weaves.! 4 '
Twill Weave Plain Weave
Figure fi.2. Weaving patterns of biaxially woven fabrics.' 4 '