Weave Diagram

The weave diagram is a graphical sketch of the weave pattern on graph paper. Each square represents a potential interlacing point of warp and weft threads. It has been standardized to represent the warp threads in a vertical direction and the 

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Figure 3.18 The weave diagram created for a three-layer quadratic hollow fabric.

Different architectures have been selected among the three main types of 3D warp interlock weave diagram as the orthogonal, the through-the-thickness and the layer-to-layer (Figure 10.7). 

Figure 10.7 3D warp interlock weave diagrams (left) layer-to-layer, (middle) orthogonal... 

Considering the three selected weave diagrams. E-glass and polypropylene commingled yams of 360 Tex linear density have been used as shown in Table 10.1. The initial thickness of these three selected architectures, as mentioned in Table 10.1, corresponds to the measurement done on the flat fabric out of the loom. 

A first comparison of the three different types of 3D warp interlock fabrics using the four measured parameters can be done and helps to highlight the influence of the weave diagram on the global behaviour of the final preform in both warp and weft directiOTis after the forming process using a semi-hemispherical punch. 

A second comparison of the three types of 3D warp interlock fabric helps to reveal a more local behaviour at each point of the final preform due to their different weave diagrams. 

Based on previous results, leading to a choice of the layer-to-layer weave diagram, an optimization of the initial 2-2 twill - layer-to-layer warp interlock fabric initially selected has been achieved to improve the forming behaviour using a gusset punch. 

Observations of the 3D warp interlock weaving of the architecture 2, based on twill 2 weave diagram (Table 17.3), help us to follow the fabric forming, where at each period, two weft yams are regularly inserted inside the fabric and the fabric production is done constantiy following these dynamic and cyclic motions as observed in Table 17.4. 

Wiegmann et al. ° have also extended the reconstraction formalism for woven microstructure generation. The reconstraction technique creates a 3D realization of a woven GDL based on structural inputs such as weave diagram, thread width, thread height and thread pitch. The inner structure of the multifilament threads is created using the number of filaments (i.e. carbon fibers), their diameter and waviness. The input parameters canbe obtained from the fabrication specifications, e.g. fi om the sample SEM micrographs or CT scans. Figure 9.8 shows a representative 3D reconstructed woven carbon cloth GDL microstracture. 

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