Weft-knitted fabric-reinforced composites

Ramakrishna S. Characterization and modeling of the tensile properties of plain weft-knit fabric-reinforced composites. Compos Sci Tech 1997 57 1-22. 

Rios CR, Ogin SL, Lekakou C, Leong KH. A study of damage development in a weft knitted fabric reinforced composite part 1 - experiments using model sandwich laminates. Compos Appl Sci Ma /2007 38(7) 1173-793. 

S. D. Pandita, D. Falconet, I. Verpoest (2002) Impact properties of weft knitted fabric reinforced composites, Compos. Sci. Technol. 62,1113. 

Wang Y, Gowayed Y, Kong X, Li J, Zhao D. Properties and analysis of composites reinforced with E-glass weft-knitted fabrics. J Compos Tech Res 1995 17 283-8. 

Three dimensional structures of multiaxial warp knitted fabrics have been recently developed for multidirectional reinforcement of composites. Multilayers of linear yams are assembled in warp (0°), weft (90°) and bias ( 0) directions to provide in-plane reinforcement in specific directions and they are stitched together by knitting yams to provide structural integrity and through the thickness reinforcement [1,2,3,4,5]. 

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). 

For the production of composites, it is normally desired that textiles used for reinforcement possess great tensile strength and an extreme stiffness. The Young s modulus of textiles has to be significantly higher than that of the matrices used (for example, plastics). Conventional warp-knitted fabrics cannot fulfill these demands. Therefore, weft-reinforced, warp-knitted fabrics (Fig. 8.3) were developed to increase the stiffness of warp-knitted fabrics. 

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