Non-crimp fabrics

Kurashiki T, Hamada K, Honda S, Zako M, Lomov SV, Verpoest I. Mechanical behaviors of non-crimp fabric composites based on multi-scale analysis. In 17th international conference on composite materials (ICCM-17). Edinburgh lOM Communications Ltd 2009. 

Manufacturers of composite structures have traditionally used prepreg tape to manufacture structural components. Fibres are initially combined into unidirectional tows (bundles) of fibres combined into fabrics, e.g. by weaving or knitting. The vast majority of the tows employed in woven, braided or knitted reinforcements comprise low twist or untwisted continuous filament yams. Three-dimensional technical textiles can be produced by weaving [5], knitting [6] and braiding [7] or as non-crimp fabrics. 

Adden S, Horst P. Damage propagation in non-crimp fabrics under bi-axial static and fatigue loading. Compos Sci Technol 2006 66 626-33. 

Adden S, Horst P. Stiffness degradation under fatigue in multiaxially loaded non-crimped fabrics. Int J Fatigue 2010 32 108-22. 

Geometrical shear stress (in-plane stress condition) Multiaxial fatigue ratio ffbAyt/ffbult Non-crimp fabric... 

Non-crimp fabric composites Manufacturing, properties and applications... 

The coating process has to deal with the special textile structure for FRC. In general non-crimped fabric structures with 0°- and 90° fiber directions are utilized. The fibers in warp- and weft direction are bonded with a knitting thread. The strength of the bond varies with the types, Tricot-and Chain-weave (... 

Of the available textile reinforcements (woven, braided, knitted, stitched), many can now be considered to be mature applications. For example, non-crimp fabric (carbon fibre) is used to manufacture the A380 rear pressure bulkhead at 240kg, in mass, 6.2m long, 5.5m wide, and 1.6m deep, this can be classed as a large structure at a smaller length scale, braided carbon fibres are now used regularly for high performance bicycle frames. 

Fig. 1.8 Schematic diagram of a non-crimp fabric with —45°, 90°, -1-45°, 90°, and 0° layers. Courtesy of SAERTEX GmbH Co. KG.

The 21st century has already seen rapid advances in the field of textile-based composites. In addition to traditional two-dimensional woven fabrics, multiaxial non-crimp fabrics are now very widely used, with a rapidly growing number of applications for braided composites. Developments in three-dimensional weaving, combining through-thickness reinforcement with excellent in-plane properties, provide new design solutions for situations where delamination must be avoided. Textile reinforcement is thus providing major new areas of opportunity for composite materials worldwide. 

Hogg PJ, Ahmadnia A, Guild FJ. The mechanical properties of non-crimped fabric-based composites. Composites 1993 24 423-32. 

Backhouse R, Blakeman C, Irving PE, et al. Mechanisms of toughness enhancemera in carbon-fibre non-crimp fabrics. In Proceedings 3rd international conference on deformation and fracture of composites. University of Surrey, Guildford, UK, Institute of Materials ... 

P(2) Non-crimp fabrics should be considered when the highest materials properties are required. 

Andersson CH, Yarn handleability and weft inserted warp knit non-crimp fabrics. Proceedings, TexComp-2, Leuven, Belgium, May 17-19, 1994. 

Starchaser Industries have launched Nova, a 11 m tall rocket fitted with cfrp cowlings [87], Man Technologies have developed a carbon composite booster case for Ariane 5 by laying up dry non-crimp fabrics on a cylindrical mandrel, using resin injection under vacuum and curing in an oven at ambient pressure. 

In addition to its use as fibers, wood is also used in particulate form (as woodflour) in polymer composites. When used as woodflour, it acts as a filler rather than a reinforcement. Wood and plant fibers are available as non-woven fiber mats and these are the most widely used preforms for composite reinforcement. Lignocellulosic fibers may also be spun into yarn which can be used to make preforms of woven fabrics and noncrimp fabrics. Woven fabrics are mostly used for textile applications while non-crimp fabrics of flax fibers have recently been introduced specifically for use as reinforcement... 

Lee, J.S., Hong Seok, J., Yu, W.-R., Kang Tae, J., 2007. The effect of blank holder force on the stamp forming behavior of non-crimp fabric with a chain stitch. Compos. Sci. Technol. 67 (3), 357-366. 

Creech, G. and Rickett, A. K. (2006), Meso-modelling of non-crimp fabric composites for coupled drape and failure analysis . Journal of Materials Science, 41, 6725-6736. 

Non-crimp fabrics (NCFs) are manufactured by stitching unidirectional yams in a layer to another layer of unidirectional yarns. If the directions of the yams in the two layers are perpendicular to each other, for example one layer is parallel to the roll direction and the other is perpendicular to it, then the NCF is referred as [0/90°].There may be many other configurations such as [0/90° /0/90°] or [0/907+45° /-45° /90° /Oj. NCF eliminates the fiber crimp, and thus high fiber volume fraction and in-plane mechanical properties can be obtained. 

In principle, all fibres available for FRP can also be used as reinforcement in prepregs, the most common ones being carbon and glass fibres. Polymeric fibres made from aramid or polyethylene are also quite coimnon, as are inorganic basalt fibres, or natural fibres like hemp or flax. Often, the fibres are directly impregnated to make unidirectional (UD) tapes. Alternatively, they can first be transformed into fabric products, such as woven fabrics or non-crimp fabrics (NCF), and then impregnated to create multi-directional prepregs. 

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