Warp interlock 3D woven fabrics

D multilayer woven fabrics made on conventional 2D weaving looms are commonly distinguished as warp interlock and weft interlock these two subcategories have certain similarities but also possess substantial differences. Warp interlock 3D woven fabrics were introduced much earlier than the weft interlock ones (see inventions in... 

Extensive work has been devoted to experimental studies of impact, blast, and ballistic responses of various 3D woven fabric composites, mainly with 3D warp interlock reinforcements. Discussing in detail all those interesting studies would be a subject of a separate chapter. Here we would like to only mention those works where 3DNCOW reinforced composites were studied. 

To sum up, the realistic as-woven geometry of the 3D warp interlock fabrics should be well represented in numerical model, and the variation of the cross-sectional shape of the yams should be taken into account. The identification of a material s mechanical behaviour law is often difficult to achieve for a 3D warp interlock structure. It should highlight here that the computational cost of the forming simulation of the thick warp interlock preform is more important as compared to the 2D fabric therefore, it should find a good balance between forming simulation accuracy and computational efficiency. 

Due to the higher thickness value of 3D warp interlock, the exact positions of warp and weft yams, respectively, located oti the top and bottom of the 3D fabric, have to be checked during the forming process. To measure the slippage between the external layers, coloured yams have been woven on the two external surfaces of the 3D warp interlock fabric to create symmetrical and regular grids (Figure 10.12). Fifty locations have been chosen and marked vis-a-vis oti upper and bottom surfaces. 

The enhanced ballistic performance of the 3D honeycomb fabrics may be attributed to the conjunction area between adjacent layers, which increases the yam friction in the conjunction area and the dimensional stability of the fabric as a whole. The increased yam friction in the conjimction area restrained yams from pulling out of the fabric in comparison to 2D plain woven fabric. Furthermore, both warp and weft yams in the conjunction area are better controlled with higher friction force caused by the higher yam density in the area. The reduced ballistic performance of 3D angle-interlock may be due to the difference in the number of intersections... 

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