Flax tows

Compression tests are a useful first step in designing densification equipment. Maximum pressures required for the desired springback or bound densities can be obtained in a ram compression chamber if heat and moisture levels are also simulated. A test on flax tow demonstrated that 100 psi (0.7 MPa) ram pressure would be required to make 16 Lb/CF (256 Kg/m ) wire bales. 

The flax tow used was manufactured by Groupe Depestele (France) [38] in the form of spools with a linear density of 500 tex. The tow consists of an agglomeration of flax fiber bundles along the tow axis, which overall cohesion is given by a natural binder. The architecture of the tow can be qualified as flat and unidirectional (Figure 5.1) the tow is 0.16 0.03 mm thick and 2.20 0.39 mm wide. 

Figure 5.3 (a) Plain weave fabric (b) flax tow (c) detailed view of flax tow (d) twill weaves fabrics. 

Ten sile B ehavior of Reinforcement Components Flax Tow Scale... 

J. Moothoo, S. Allaoui, R Ouagne, and D. Soulat, A study of the tensile behaviour of flax tows and their potential for composite processing. Mater. Des. 55,764-772 (2014). 

The flax fiber from the aimual plant IJnum usitatissimum (flax family, Liuaceae) has been used siuce ancient times as the fiber for linen. The plant grows iu temperate, moderately moist climates, for example, iu Belgium, France, Ireland, Italy, and Russia. The plant is also cultivated for its seed, from which linseed oil is produced. A by-product of the seed plant is the tow fiber used iu papermakiug. 

Julius Africanus mentioned shooting Powder , but its compn was not given 350 AD. Aeneus of Rome put sulfur, pitch, incense, pine-rosin, and tow (crude flax fibers) into an oval wooden container, ignited the mixture and threw it on the decks of enemy ships (Ref 66, p 12)... 

Fibre crops Flax fibre and tow Seed cotton... 

Tow The coarse and broken part of flax, hemp or Jute, separated and ready for spinning. 

Keywords Flax, composite, manufacturing processes, fabric/textile, fabric mechanical behavior, preforming, tow, forming defect, tow buckling... 

The modification of the tow orientation and local variations of fiber volume fraction have a significant impact on the resin impregnation step as the local permeabilities (inplane and transverse) of the reinforcement may be affected [30,31]. In the most severe cases, the ply of fabric can wrinkle or lose contact with the mould, hence severely reducing the quality of the finished product [32]. Another defect called tow buckling has also been reported for flax woven fabrics [33,34]. As the quaHty of the preform is of vital importance for the final properties of the composite parts, it is important when forming of complex shape is considered to prevent the appearance of such defects. 

Two different flax fabrics (Figure 5.3) are used in this study. The first one is a plain weave fabric with an areal weight of 280 19 g/m, manufactured by Groupe Depestele (France) [38]. The fabric is not balanced, as the space between the weft tows (1.59 0.09 mm) is different to the one between the warp tows (0.26 0.03 mm). The widths... 

To calculate the apparent tensile strength and modulus, the cross-sectional area of the tow was estimated by dividing its linear density (500 tex) by that of its constituent fiber, flax, taken as 1.53 g/cm [4]. 

E. Capelle, P. Ouagne, Tephany, D. Soulat, D. Duriatti, and S. Gueret. Analysis of the tow buckling defect during the complex shape forming of a flax woven fabrics. Proceedings of the 15TH European Conference on Composite Materials, Venice, Italy, 24-28 June (2012). 

P. Ouagne, D. Soulat, J. Moothoo, E. Capelle, and S.Gueret, Complex shape forming of a flax woven fabric analysis of the tow buckling and misalignment defect. Compos. A 51, 1-10 (2013). 

Ouagne, P., et al., 2013b. Mechanical characterisation of flax-based woven fabrics and in situ mea-suremraits of tow traisile strain during the shape forming. J. Compos. Mater. 47,3501 3515. 

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