Page 25 - 3D Fibre Reinforced Polymer Composites

14 30 Fibre Reinforced Polymer Composites

mechanically or electronically operated and may allow individual yarns to be selectively
controlled (jacquard loom) or control a set of yarns simultaneously (loom with shafts, as
shown in Figure 2.1). The crucial point is that the lifting mechanism selects and lifts the
required yarns and creates a space (the shed) into which the weft yarns are inserted at
right angles to the warp (the 90" direction). The sequence in which the warp yarns are
lifted controls the interlinking of the warp and weft yarns and thus the pattern that is
created in the fabric (see Figure 2.2). It is this pattern that influences many of the fabric
properties, such as mechanical performance, drapability, and fibre volume fraction.
Therefore to manufacture a suitable 2D or 3D preform an understanding of how the
required fibre architecture can be produced through the design of the correct lifting
pattern is crucial in the use of this manufacturing process.

/ / \

Heddles Reed \
Shuttle with weft yam
Figure 2.1 Illustration of conventional weaving process

PLAIN TWILL SATIN
WEAVE 2x2 5HS
Figure 2.2 Typical 2D weave patterns