Fibres distribution

At the point of contact between the cellulosic fibres a strong bond is formed once the fibres have been dried. These bonds are formed by hydrogen bonds between the polysaccharides at the fibre surface. Mechanical and other properties of paper are not only dependent on the nature of the fibre distribution but also on the bonding between the fibres and the inherent fibre strength itself. Bonding between... 

The polished samples are sputtered with a thin layer of gold for analysis in a scanning electron microscope (SEM), a Jeol JSM 35c fitted with a link AN 10000 energy-dispersive X-ray spectrometer (EDS). The fractured surfaces and polished sections through fractured specimens can also be prepared and analysed in this manner. SEM analysis may reveal a non-uniform fibre distribution in the composite. In composites sintered at different temperatures, cracking in the matrix phase and residual porosity can be identified and the filler particles are discernible. The EDS indicates the higher particles and the matrix constituents. 

Figure 2 shows an aluminium liner (old version) on which the first layer is deposed. This equipment allows controlling the displacement of the fibre distribution cell along 4 axes x, y, z and w, that is the rotation of the mandrel. 

Gibbs AR, Stephens M, Griffiths DM, et al. 1991. Fibre distribution in the lungs and pleura of subjects with asbestos related difiuse pleural fibrosis. Br J Ind Med 48 762-770. 

Lovell, C.R. et al.. Type 1 and 111 collagen content and fibre distribution in normal human skin during ageing, Br. J. Dermatol, 117 (4), 419 28. 1987. 

Grishanov S A, Lomov SV, Harwood RJ, Cassidy T. The simulation of the geometry of two-component yams. Part II. Fibre distribution in the yam cross-section. J Text Inst 1997 88 part l(4) 352-72. 

Gommers B, Verpoest I, van Houtte P. Analysis of knitted fabric reinforced composites part 1. Fibre distribution. Compos Appl Sci Afaww/1998 29 1579-88. 

Better distribution of the mechanical properties of the moulded part, i.e., no areas without or with little glass, due to a more homogeneous glass fibre distribution in the mould, because of the special distribution system. 

Improvements in mechanical and physical properties are dependent on fibre t3q)e, amount of fibre added and fibre distribution. Consistency of properties is more difficult to control. 

Anisotropy and fibre distribution in the case of short GF reinforced items cause the biggest disadvantage in injection moulding, as regards the final mechanical performance, however, the economy of process with short GF is much more promising than use of continuous fibres. 

Ravbala, N., Gong, R.H., 2003. Effects of mould porosity on fibre distribution in a 3D nonwoven process. Text. Res. J. 73, 588-592. 

Benson, S.D.P., Nicolaides, D., Karihaloo, B.L., 2005. CARDIFRCl - Development and mechanical properties. Part II Fibre distribution. Magazine of Concrete Research, 57(7), pp. 421 32. 

This group of materials, also called fibre-reinforced concretes (FRC), contains concretes and mortars reinforced with short fibres, distributed at random or arranged in a certain way also as mats and fabrics. The fibres are of different materials steel, glass, polypropylene, asbestos, etc., as well as natural organic... 

Granular soil with fibre reinforcement is a material composed of granular natural soil (i.e. sand) and thin continuous fibres distributed in the material volume with or without cement or any other binding agent. The synthetic (polyester, polypropylene or polyamide) fibres are very thin and their volume fraction is low starting from 0.1% or 0.3% also natural fibres may be used (e.g. sisal, coir). The fibres are distributed in a uniform and isotropic way (3D) or are parallel to a selected plane (2D). The main influence of the reinforcement is the cohesion of sand, which is enhanced with the fibre content, while the angle of the internal friction remains constant. 

The execution of operations aimed at the realization of designed fibre structure requires special care and control. The effective fibre distribution and direction may be determined after the analysis of images obtained on... 

Examples of fibre distribution are shown in radiograms in Figure 6.22. 

In any type of fibre distribution the balling of fibres and their agglomerations... 

Figure 6.23 Parameters describing fibre distribution, after Kasperkiewicz (1983). 

The specimens were prepared with the same mix proportions and fibre distribution as described in Brandt (1986). The reinforcement was made with mild steel round and straight wire 0.4 mm in diameter, continuous or chopped into 40 mm fibres. The results reported here concern only one volume fraction of continuous or short fibres V = 0.67%. The fibre orientation of various series of specimens is shown in Figure 8.21, the angle 0 being measured between aligned fibres and the longitudinal axis of the... 

Figure 10.19 Nominal stress-apparent strain curves after measurements at the bottom and top faces of SFRC elements subjected to bending. The curves correspond to ID and 2D fibre distributions and to various fibre volume content, after Babut (1983).

The formulae for calculation of particular components W- were derived in above-mentioned papers for different situations short or continuous fibres, random fibre distribution ID, 2D or 3D, axial tension or bending. These formulae were also applied in optimization problems (cf. Chapter 12). A simple case of ID fibres in an element subjected to tension with a crack of given limit width is described more in detail below according to Brandt (1985). 

---