**6.3. Space and aerospace applications**

mechanisms for weft knitted structures were dependent on both the wale and the course directional crack propagations, and demonstrated better interlaminar fracture toughness properties due to the 3D loop structure [49]. It was found that the failure process of weft knitted structures under tensile load includes crack branching, loop to loop friction, yarn bridging and fiber breakages. It was also shown that an increase in loop length or stitch density has opposite effects on the tensile strength and impact performance of the weftknitted composites. The plain weft knitted structure exhibited good energy absorption capacity. Matrix cracking, matrix/fiber debonding, and fiber breakage were the major damage mechanisms [36, 49, 109]. The 3D loop structure was studied, and it was pro‐ posed that the loop structure was constituted by sets of arcs. Adoption of the arc shape loop geometry into micromechanical technique considers the influence of knitting parame‐

Two- and three-dimensional woven, braided, knitted and nonwoven composites as structural components for various industrial applications fulfilled the general requirements such as low cost, manufacturability, good mechanical performance and energy absorption, corrosion resistance, repairability and recyclability, fuel economy and low noise level [149]. Typical structural components in various industrial applications are knot elements for space framelike structures, beams, shells, exhaust, seats and chassis. For instance, the use of woven and braided composites in structural applications allows a significant reduction in component number and provides a substantial weight reduction compared with metal [87]. In addition, 2D and 3D woven, braided and knitted composites as T-joints and T-shape connectors, cones, pipes, and I-beams are attractive applications in general engineering fields. Two- and threedimensional nonwoven composites can be used in construction industry as a roofing and tile underlay, thermal and noise insulation, and house wrap. Some geotextile applications of 2D or multilayerd 3D nonvoven composites are asphalt overlay, soil stabilization, drainage, sedimentation and erosion control. Industrial applications of the 2D or 3D nonwoven struc‐ tures are cable insulation, battery separators, satellite dishes and coating [149]. The 2D nonwoven nano web structures are increasingly finding applications in filtration industry, electromagnetic interference (EMI) shielding, electrical conductors, thermal and lightning protection, energy field in batteries, photovoltaic cells, polymer electrolytes and membrane

Two- and three-dimensional woven fabric and rigid ballistic plate are used extensively to protect the human and goods from various threats such as projectile, blast, fragment and high energy explosives. In addition, 2D and 3D braided, knitted and nonwoven fabrics and rigid composites can be utilized as protective products for vehicular crash guards, composite

ters and the estimation of elastic properties of knitted composites [148].

**6. Application of fabrics in technical textiles**

fuel cells and advanced structural composites.

**6.2. Ballistic applications**

**6.1. Structural components**

126 Non-woven Fabrics

Two- and three-dimensional woven and braided fabrics are used in aerospace applications as soft space suits for astronauts, space shuttle components and aircraft seat cushions. Two- and three-dimensional woven, braided and multiaxis warp knitted composites are currently employed in critical structures of both civil and military aircrafts such as the fuselage, wings, and skin of the aircraft. Other areas of use are top and side tail units, fuselage panelling, leading edges on side rudders, and engine panelling. It was reported that multiaxis 3D warp knitted composites are also being evaluated for rotor blades, outer skin and ballistic protection for helicopters. Three-dimensional weft or warp knitted ceramic composite was also developed for use as a structural parts for jet engine vanes, radomes and rudder tip fairing [49].
