Woven composite materials

Alternatively, tests can be used to obtain the basic stiffness properties of the material form and their corresponding range measured by some statistical property such as the standard deviation. In two-dimensional cases where there are no significant loads in the out-of-plane direction, the basic orthotropic stiffness properties in Eqn (6.1) can be measured experimentally. Then, the classical laminated plate theory described in previous sections for determination of stiffness can be used effectively to model these sttuctures. Alternatively, the four basic stiffiiesses for 3-D woven composites can be 

However, especially for three-dimensional stmcture, or, even, in two-dimensional stmcture with significant out-of-plane loads, the stiffness averaging of the classical laminated plate theory is not sufficient. In such cases, a specialized finite element model such as the binary model by Cox, Carter, and Fleck [25] can be used. In this model, Monte Carlo simulation allows the user to randomly orient tows and to randomly assign strength properties to the different components. 

Final in-plane failure under tension is caused by fiber breakage. Under compression, the dominating mechanism is kink-band formation and fiber microbuckling. 

For typical 3-D woven fabrics, the misalignment angle can be assumed to be normally distributed with mean equal to zero and a standard deviation around 5—6° [24]. 

In the presence of shear stresses, kink-band formation is still possible, but now the buckling stress is reduced [24]  

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S.B. Sharma, M.P.F. Sutcliffe, and S.H. Chang, Characterisation of material properties for draping of dry woven composite material. Compos. A 34,1167-1175 (2003). 

LeBlanc, J., Shukla, A., Rousseau, C., Bogdanovich, A., 2007. Shock loading of three-dimensional woven composite materials. Compos. Struct. 79 (3), 344—355. 

Mcllhagger, R., HiU, B.J., Brown, D., Limmer, L., 1995. Construction and analysis of three-dimensional woven composite materials. Compos. Eng. 5 (9), 1187-1197. 

Lee, C., Chimg, S., Shin, H., Kim, S., 2005. Virtual material characterization of 3D orthogonal woven composite materials by large-scale computing. J. Compos. Mater. 39, 851 63. 

CNF is an industrially produced derivative of carbon formed by the decomposition and graphitization of rich organic carbon polymers (Fig. 14.3). The most common precursor is polyacrylonitrile (PAN), as it yields high tensile and compressive strength fibers that have high resistance to corrosion, creep and fatigue. For these reasons, the fibers are widely used in the automotive and aerospace industries [1], Carbon fiber is an important ingredient of carbon composite materials, which are used in fuel cell construction, particularly in gas-diffusion layers where the fibers are woven to form a type of carbon cloth. 

This also applies to the macroscopic properties of composite materials with underlying symmetry—like honeycomb, wood, and woven materials—for which the crystal structure, if any, may play no direct role. 

Engineering thermoplastics have also been used in preimpregnated constructions. The thermoplastic is thoroughly dispersed as a continuous phase in glass, other resins, carbon fibers (qv), or other reinforcement. Articles can be produced from these constructions using thermoforming techniques. For example, the aerospace industry uses polyetheretherketone (PEEK) in woven carbon-fiber tapes (26). Experimental uses of other composite constructions have been reported (27) (see also COMPOSITE MATERIALS, POLYMER-MATRIX). 

Kastritseas, C., Smith, P.A., Yeomans, J.A. (2004b), Damage characterisation of thermally-shocked woven fibre-reinforced ceramic matrix composites , Proceedings of the 11th European Conference in Composite Materials (ECCM-11), Rhodes, Greece, Vol. 2. 

This configuration of reinforcement occurs when fibers are woven into a mat. It could also represent whisker-reinforced materials in which the whiskers are randomly oriented in the plane, especially if uniaxial pressing has been used to consolidate the composite material. In the case of the whisker-... 

In a simple model for this case, which, as in the 3-D case, ignores fiber straightening and anisotropy of the fibrous network, a plane stress version of Eqn. (35) can be developed. As such, it can only be used for plane stress states. Consider the x-y plane to be that in which the fibers are woven or the whiskers are lying. The strain rates in this plane are taken to be homogeneous throughout the composite material and crzz, axz and ayz are taken to be zero. The resulting law is... 

Besides the commonplace uses as textiles and the more sophisticated uses as reinforcements to make composite materials, woven fabrics made of a fibrous yam can be used to make versatile yet low cost structures. Such construction alternatives can provide the following advantages ... 

The results described in this paper were all obtained from tests on E-glass reinforced composite materials produced by hand lay-up. This is the manufacturing route most frequently used for marine structures. For the majority of the tests reported here the E-glass fibres were either quasi-unidirectional (250 g/m with 1 g/m of polyester fibres bonded in the 90° direction to keep the UD fibres in place) or stitched quadrlaxial (0/45/907-45° 1034 g/m ) cloths. The same uniaxial ply is used in both cloths. The resin is based on DGEBA epoxy (SRI500) with an amine hardener (2505) from Sicomin, France. All epoxy specimens were post-cured at 90°C for 6 hours. Some results are also shown for a woven glass (0/90° 500 g/m ) reinforced isophthalic polyester for comparison, as this is the traditional marine... 

In general, textiles used in wound-dressing products include fibres, nanofibres, filaments, yarns, and woven/knitted/non-woven and composite materials. 

Textile materials can be used in moist wound management as fibres themselves (advanced fibres such as alginate and chitosan fibres), or conventional/advanced fibres can be modified or coated with various substances such as honey or hydrogels to obtain special properties such as ultra-absorbency, drag release, etc. In general, textiles used in wound-dressing products come in all possible forms, including fibres, nanofibres, filaments, yarns, and woven/knitted/non-woven and composite materials. 

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