*4.2.5.1. By 6-step braiding method*

This method employs ±braider yarns, warp (axial), filling, and z-yarns. In order to form the fabric, the braider yarns are intertwined with the orthogonal yarn sets. The properties of the multiaxial 3D braided structure in the transverse direction are enhanced and the directional Poisson's ratios of the structure are identical. In this process, there are six distinct steps in each cycle. Steps 1 and 2 are identical to the 4-step method. Step 3 inserts yarn in the transverse direction. Steps 4 and 5 are identical to the steps 1 and 2, and step 6 inserts yarn in the thickness

**Figure 37.** (a) 3D flat and (b) 3D circular axial braiding machines [91].

direction [77]. Another multiaxial 3D braided fabric produced by the 6-step method consists of ±bias, warp (axial), radial (z-yarns) and ±braider yarns. ±Bias yarns are oriented in-plane whereas the others are positioned out-of-plane [78]. The axial and braider yarns are inter‐ twined with each other while ±bias yarns are positioned at the surface of the preform and secured by the radial yarns to the other yarn sets. The process takes place over six steps in each cycle. In steps 1 and 2, ±braider yarns are intertwined around the axial yarns as in the 4-step method. In step 3, ±bias yarns are laid down on the surface of the structure. In step 4, the radial yarns move in the thickness direction of the structure and lock the ±bias yarns to the ±braider and axial yarns. In steps 5 and 6, the ±braider yarns are intertwined around the axial yarns as in the 4-step method.

## **4.3. Nonwoven**

individually controlled gripping forks, which can quickly move yarn carriers between the horn

This method employs ±braider yarns, warp (axial), filling, and z-yarns. In order to form the fabric, the braider yarns are intertwined with the orthogonal yarn sets. The properties of the multiaxial 3D braided structure in the transverse direction are enhanced and the directional Poisson's ratios of the structure are identical. In this process, there are six distinct steps in each cycle. Steps 1 and 2 are identical to the 4-step method. Step 3 inserts yarn in the transverse direction. Steps 4 and 5 are identical to the steps 1 and 2, and step 6 inserts yarn in the thickness

gears according to a pre-determined pattern [97].

**Figure 36.** Schematic view of the 3D axial braiding by 2-step braiding [74].

*4.2.5. Multiaxis 3D braided fabric*

110 Non-woven Fabrics

*4.2.5.1. By 6-step braiding method*
