*4.1.1. Two-dimensional weaving*

The 2D woven fabric is the most widely used material in the composite industry with a share of about 70%. Traditional weaving machine (Figure 23) is used to manufacture the fabric [4, 84]. This machine is constituted of several units such as warp let-off, fabric take-up, shedding, weft insertion and beat-up. Recently, traditional weaving machine was modified to weave high modulus fibers such as carbon, E-glass, S-glass, and para-aramid. The machine is capable of weaving a range of fabric types and patterns including plain, twill, satin, and leno. It is also possible to fabricate hybrid fabrics by incorporating different fiber types in warp or weft yarns. Another approach is to use warp and weft yarns consisting of different types of fibers [4].

**Figure 23.** Schematic view of 2D weaving and shedding unit [4, 84].

#### *4.1.2. Triaxial weaving*

Triaxial weaving machine consists of multiple ±warp beams, filling insertion, open beat-up, rotating heddle and take-up unit, as shown in Figure 24. Warp beams are located above the machine. ±Warp yarns unwind from these beams and head to a separation unit where the warp yarns from each beam are separated into two layers. Then these layers are fed vertically into the interlacing zone. The front layer is directed to the right, whereas the rear layer heads to the left. The directions are reversed after the outmost warp end reaches the edge of the fabric. As a result, the warp makes the bias intersecting in the fabric. Special hook heddles govern the shedding action by shifting after each pick. Two opposite reeds that are positioned in the front and back sides of the warp layers beat up the pick [45]. In order to make quart-axial fabric, warp yarns are inserted to the triaxial woven fabric at selected places depending upon the enduse. After that, ±bias yarns rotate just one bobbin distance and heddles are shifted one heddle distance. Then warp is fed to the weaving zone and the shedding action is carried out by the heddles. Filling yarn is inserted and is beaten against the fell to complete the fabric formation. Finally, the fabric is removed from the weaving zone with the aid of a take-up unit [45].

**Figure 24.** (a) Schematic view of (b) actual triaxial weaving loom [45, 85].

## *4.1.3. Three-dimensional weaving*

**4. Fabrication of fabrics**

*4.1.1. Two-dimensional weaving*

**Figure 23.** Schematic view of 2D weaving and shedding unit [4, 84].

*4.1.2. Triaxial weaving*

The 2D woven fabric is the most widely used material in the composite industry with a share of about 70%. Traditional weaving machine (Figure 23) is used to manufacture the fabric [4, 84]. This machine is constituted of several units such as warp let-off, fabric take-up, shedding, weft insertion and beat-up. Recently, traditional weaving machine was modified to weave high modulus fibers such as carbon, E-glass, S-glass, and para-aramid. The machine is capable of weaving a range of fabric types and patterns including plain, twill, satin, and leno. It is also possible to fabricate hybrid fabrics by incorporating different fiber types in warp or weft yarns. Another approach is to use warp and weft yarns consisting of different types of fibers [4].

Triaxial weaving machine consists of multiple ±warp beams, filling insertion, open beat-up, rotating heddle and take-up unit, as shown in Figure 24. Warp beams are located above the machine. ±Warp yarns unwind from these beams and head to a separation unit where the warp yarns from each beam are separated into two layers. Then these layers are fed vertically into

**4.1. Weaving**

100 Non-woven Fabrics

In order to make the representative 3D plain woven preform, the warp must be arranged in a matrix of rows and columns, as shown in Figure 25. The first step is the one-step sequential movement of an even number of warp layers in the column direction (a2). This was accom‐ plished with the aid of a 2D shedding unit (not shown). The second step is to insert filling yarn between each warp layer in the row direction (a3). The third step is the one-step sequential movement of an even number of warp layers in the row direction (a4). This was also accom‐ plished via the 2D shedding unit. The fourth step is z-yarn insertion between each warp layer in the column direction (a5). After fulfilling the cycle of steps (a2-a5), 3D woven fabric is formed (a6). The length of the preform determines the number of cycles to be performed. Figure 25 shows the pattern of 3D plain-z yarn orthogonal preform. Steps (a1-a6) are followed to form the fabric structure. Z-yarn is inserted with no interlacement (a4-a6) Again, the preform dimensions determine how many warp layers to be used in the row and column directions [60].

Figure 26 shows the steps necessary to form a 3D circular plain woven fabric. In such an arrangement, axial yarns are positioned in a matrix of circular rows and radial columns according to desired cross section. The first step in the process is the one-step sequential movement of an even and odd number of axial layers in the radial column direction (a2). This


**Figure 25.** Three-dimensional weaving method to make representative fully-interlaced woven preforms; 3D plain wo‐ ven preform (a1-a6) [60].

can be accomplished via a 2D circular shedding unit (not shown). The second step is to insert circumferential yarn between each axial layer in the circular row direction (a3). The third step is the one-step sequential movement of an even and odd number of axial layers in the circular row direction (a4) which is also accomplished with the aid of the 2D circular shedding unit. The fourth step is radial yarn insertion between each axial layer in the radial column direction (a4). The 3D circular plain woven preform is formed (a5) after repeating the steps (a2-a4). The length of the preform determines the number of repeats. The unit cell of 3D orthogonal circular woven preform consists of three yarn sets such as axial, circumferential and radial yarns. Axial yarns are arranged in a matrix of circular rows and radial columns. Circumferential yarns are single-end and are laid down between each adjacent axial yarn row. Radial ends are positioned between each axial row through the preform thickness and they locked all other yarn sets. Hence the structural integrity of the preform is achieved. An individual shuttle for circumfer‐ ential yarn that is mounted on each individually rotated ring was used for the preform fabrication. In addition, the radial carriers reciprocated linearly to the radial corridor of the 2D shedding plane on the rig thus crossing the radial yarns in the preform structure (crossing shedding) [61].

**Figure 26.** Three-dimensional weaving method to make representative fully-interlaced circular woven preform; 3D cir‐ cular plain woven preform (a1-a5) [61].

The state-of-the-art weaving loom was modified to make 3D orthogonal woven fabric [86]. For instance, one of the looms which has three rigid rapier insertions with dobby type shed control systems was converted to make 3D woven preform. The new weaving loom was also designed to make various sectional 3D woven preform fabrics [23]. The 3D circular weaving method and fabric (or 3D polar weaving) were developed [63]. The device consists of a table that can rotate and a pair of carriers. The table holds the axial yarns. Each carrier contains radial yarn bobbins together with a guide frame to regulate the weaving position. The main task of the carriers is to move vertically up and down in order to insert the radial yarns. A circumferential yarn bobbin is placed radial to axial yarns. After the circumferential yarn is wound over the vertically positioned radial yarn, the radial yarn is placed radially to outer ring of the preform.

Multiaxis 3D woven fabric, method and machine based on lappet weaving principals were introduced by Ruzand and Guenot [65]. The basis of the technique is an extension of lappet weaving in which pairs of lappet bars are reused on one or both sides of the fabric. Uchida et al. [66] developed a fabric called five-axis 3D woven which has five yarn sets such as ±bias, filling, warp and z-fiber. The process includes a bias rotating unit; filling and z-yarn insertion units; warp, ±bias and z-fiber feeding units; and a take-up unit. The yarns are oriented by the rotation of horizontal bias chain while the filling is inserted to the fixed shed. All yarns are locked together by z-yarns. This is followed by beat-up and fabric take up procedures. Mohamed and Bilisik [30] developed a multiaxis 3D woven fabric, method and machine. This fabric is constituted from five yarn sets, such as ±bias, warp, filling and z-yarns. ±Bias yarns are placed on the front and back face of the structure. These yarns are locked to the other yarn sets by the z-yarns. Warp yarns, on the other hand, generally lay at the center of the preform (Figure 27). This formation generally improves the composite in-plane properties.

can be accomplished via a 2D circular shedding unit (not shown). The second step is to insert circumferential yarn between each axial layer in the circular row direction (a3). The third step is the one-step sequential movement of an even and odd number of axial layers in the circular row direction (a4) which is also accomplished with the aid of the 2D circular shedding unit. The fourth step is radial yarn insertion between each axial layer in the radial column direction (a4). The 3D circular plain woven preform is formed (a5) after repeating the steps (a2-a4). The length of the preform determines the number of repeats. The unit cell of 3D orthogonal circular woven preform consists of three yarn sets such as axial, circumferential and radial yarns. Axial yarns are arranged in a matrix of circular rows and radial columns. Circumferential yarns are single-end and are laid down between each adjacent axial yarn row. Radial ends are positioned between each axial row through the preform thickness and they locked all other yarn sets. Hence the structural integrity of the preform is achieved. An individual shuttle for circumfer‐ ential yarn that is mounted on each individually rotated ring was used for the preform fabrication. In addition, the radial carriers reciprocated linearly to the radial corridor of the 2D shedding plane on the rig thus crossing the radial yarns in the preform structure (crossing

**Figure 25.** Three-dimensional weaving method to make representative fully-interlaced woven preforms; 3D plain wo‐

**Figure 26.** Three-dimensional weaving method to make representative fully-interlaced circular woven preform; 3D cir‐

The state-of-the-art weaving loom was modified to make 3D orthogonal woven fabric [86]. For instance, one of the looms which has three rigid rapier insertions with dobby type shed control systems was converted to make 3D woven preform. The new weaving loom was also designed to make various sectional 3D woven preform fabrics [23]. The 3D circular weaving method and fabric (or 3D polar weaving) were developed [63]. The device consists of a table that can rotate and a pair of carriers. The table holds the axial yarns. Each carrier contains radial yarn bobbins together with a guide frame to regulate the weaving position. The main task of the

shedding) [61].

ven preform (a1-a6) [60].

102 Non-woven Fabrics

cular plain woven preform (a1-a5) [61].

**Figure 27.** (a) Schematic view of multiaxis weaving machine (b) Side view of multiaxis weaving machine [30, 67].

The warp yarns are arranged in a matrix of rows and columns within the desired cross-section. First, a pair of tube rapiers positions the front and back bias yarns relative to each other. This is followed by the incorporation of filling yarns via needles between warp rows. Then selvedge and latch needles lock the filling yarns by using selvage yarns before returning to their starting position. Z-yarns are inserted across the filling yarns by z-yarn needles. Then filling needles insert the filling yarns and these yarns are locked by selvage needles located at the opposite side of the preform. After that, the filling needles return to their initial position. Then bias yarns and filling yarns are secured in place by z-yarns which return to their initial position by traveling between the warp yarns. This is followed by beat up and fabric take-up procedures. Bilisik [28] developed a multiaxis 3D circular woven fabric, method and machine. The preform consists of axial and radial yarns together with circumferential and ±bias layers (Figure 28). The axial yarns (warp) are arranged in radial rows and circumferential layers within the desired cross section. ±Bias yarns are placed outside and inside ring of the cylinder surface. Filling (circumferential) yarns lay between each warp yarn helical corridors. In order to achieve the cylindrical form, radial yarns (z-yarns) are linked with other yarns. The thickness of the preform section can be adjusted regarding the end-use. The process requires a machine bed, ±bias and filling ring carriers, a radial braider, a warp creel and a take-up unit. First, shedding mechanism orients the bias yarns at an angle of ±45˚ to each other. Then the carriers wind the circumferential layers by rotating about the adjacent axial yarns. Special carrier units insert the radial yarns and link the circumferential yarn layers with ±bias and axial layers. Then the fabric is removed from the weaving zone by take-up unit. This process results in enhanced torsional properties for both preform and composite owing to bias yarns.

**Figure 28.** Schematic view of multiaxis 3D circular weaving loom [28, 68].

#### **4.2. Braiding**

#### *4.2.1. Three-dimensional braiding*

Two-dimensional braiding is a simple traditional textile based process to make bias fabric. A typical braiding machine consists of a track plate, a spool carrier, a former, and a take-up. The track plate supports the carriers, which travel along the path of the tracks. The movement of the carriers can be provided by horn gears, which propel the carriers around in a maypole arrangement. The carriers are devices that carry the yarn packages around the tracks and control the tension of the braiding yarns. At the point of braiding, a former is often used to control the dimension and shape of the braid. The braid is then delivered through the take-up roll at a predetermined rate. If the number of carriers and the take-up speed are properly selected, the orientation of the yarn (braiding angle) and the diameter of the braid can be controlled. Braiding can take place in horizontal or vertical direction [87].
