3-D braids

Fig. 2.7 The tensile stress-strain curves versus temperatures for (a) unidirectional SCS-6 fiber-reinforced hot-pressed Si3N4, (b) unidirectional SCS-6 fiber-reinforced reaction-bonded Si3N4, (c) 2-D Nicalon fabric-reinforced CVI-SiC, and (d) 3-D braided Nicalon fabric-reinforced CVI-SiC.49-52...

Figure 6.35 shows the deposition quality on both sides of a domed component when it is placed in Figure 6.34b for deposition. The component is a fibre preform prepared by the 3-D braiding method. The outside of the component is smooth whereas the inside is very coarse. 

LAS glass-ceramic matrix composite reinforced by 3-D braid Nicalon yarns and SiC monofdaments in (he axial direction. Tensile strength 656 MPa Aerospace [2]... 

The precursor fiber type for reinforcing the carbon matrix can be an oxidized PAN fiber (opf), or either a PAN or pitch based carbon fiber. In some instances, for special applications, such as the Shuttle, a cellulose based carbon fiber is used. The reinforcements can be unidirectional have a random chopped fiber presentation as in a felt format a woven product from continuous fiber presented in a 2D, 3D, or in a Multi-D format (Section 21.1), or a non-woven carbon fiber. The chosen fiber architecture is most important for a given application and Lei et al [4] describe how, for example, 3-D braiding can be applied to carbon-carbon composites. One of the early forms of near net shape reinforcement used for carbon-carbon aircraft brakes was based on a weft knitted 3-D fabric made by the Pressure Foot process (Figure 14.1). 

Laourine E, Schneider M, Wulfhorst B, Pickett A, Production and analysis of 3-D braided textile preforms for composites. Proceedings, TexComp-5, Leuven, Sep 18-20, 2000. 

Kostar TD, Chou TW, Design and automated fabrication of 3-D braided preforms for advanced structural composites, Computer Aided Design in Composite Material Technology III, Elsevier Science, 63-78, 1992. 

FA Kiimpers, Rheine, Germany—manufacture true multiaxial paramax fabrics and 3-D braidings. 

Bogdanovich, A., Bradford, P., Mungalov, D., Fang, S., Zhang, M., Baughman, R.H., Hudson, S., 2007. Fabrication and mechanical characterization of carbon nanotube yams, 3-D braids, and their composites. SAMPE J. 43 (1), 6-19. 

Mtmgalov, D., Bogdanovich, A., 2004. Complex shape 3-D braided composite preforms structural shapes for marine and aerospace. SAMPE J. 40 (3), 7-20. 

Bogdanovich, A.E., Mungolov, D., 2002. Recent advancements in manufacturing 3-D braided preforms and composites. In ACUN-4, pp. 61-72. 

Three-Dimensional Braid (3-D braid) A recent development in building reinforcement performs for complex shapes that permits the placing of reinforcing fibers in three orthogonal (or nonorthogonal) directions so as to best support multidirectional stresses expected to act on the finished part in service. 

It is reported that no visible damage to the nanotube yams is imparted by the braiding process and the 3-D braids are very fine, extremely flexible, hold sufficient load, and are well suited for the use in any other textile formation process, or directly as reinforcement for composites. The reported elastic and strength properties of carbon nanotube composites so far are rather low in comparison with conventional continuous carbon fiber composites. It is believed that the properties can be substantially improved if the processing methods and stmctures are optimized [191]. 

FIGURE 7.5 (a) Schematic of 3-D woven fabric incorporating very fine CNT yam as through thickness (Z) reinforcement (b) Schematic of square 3-D braided hybrid preform with large axial fiber bundles and very fine CNT off-axis braided yams... 

Figure 7.2 Design of braid stands (2-D) (left) and 3-D braids (right)...

One-Step production Manufacturing of the near-net-shaped product in a single process step (such as contour warp knitting, 3-D braiding). 

Figure 7.17 Types of 3-D braids (a) multilayered circular, (b) profile-like, (c) component-shaped...

Profile-like 3-D braids For this group, Busgen summarizes all braids with solid profiles that do not change in cross section. 

Component-shaped 3-D braids The profiles of this group of braids are variable because of individually adjustable braiding threads. The cross section can be varied both continuously and discretely. 

D braids (composite plastics, concrete reinforcement, medical textiles). 

Further development of braiding machines for the production of 3-D braids to obtain larger and more complex cross sections for nearly every application. Definition of algorithms between machine controls and the position of threads in the braid. 

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