Multiple fiber composite

A modified shear-lag model has been proposed by Rosen (1964, 1965) based on a multiple fiber composite. Fig. 4.4 shows the composite model Rosen considered wherein a fiber is embedded in a matrix which in turn is surrounded by an average composite material. The FAS and IFSS are given in the same form as those of Eqs. (4.1) and (4.2) given earlier by Cox (1952) ... 

To analyze the stress transfer in the fiber pull-out test of a multiple fiber composite, the specimen is treated as a three-cylinder composite (Zhou and Mai, 1992) where a fiber is located at the center of a coaxial shell of the matrix, which, in turn, is surrounded by a trans-isotropic composite medium with an outer radius fl. 

The filaments of all plant fibers consist of several cells. These cells form crystalline microfibrils (cellulose), which are connected together into a complete layer by amorphous lignin and hemi-cellulose. Multiple layers stick together to form multiple layer composites, filaments. A single cell is subdivided into several concentric layers, one primary and three secondary layers. Figure 5 shows a jute cell. The cell walls differ in their composition and in the orientation of the cellulose microfibrils whereby the characteristic values change from one natural fiber to another. 

An FRP pipeline typically consists of (1) an inner nonpermeable barrier tube that transports the pressurized gas, (2) a protective layer over the barrier tube, (3) an interface layer over the protective layer, (4) multiple glass or carbon-fiber composite layers, (5) an outer pressure barrier layer, and (6) an outer protective layer. Each of the layers provides a distinct function and the interaction between the layers produces a pipe with exceptional performance. 

Fig. 3.13. Schematic drawing of slice compression test on a composite slice containing multiple fibers.

Aveston, J., Cooper, G.A., Kelly, A. (1971), Single and multiple fracture , in The Properties of Fiber Composites, IPC Science Technology Press, Guildford, UK, 15-22 Bahr, H.A., Weiss, H.J., Maschke, H.G., Meissner, F. (1988), Multiple crack propagation in strip caused by thermal shock , Theor. Appl. Fract. Mech., 10, 219-226. Bannister, M.K., Swain, M.V. (1990), Thermal shock of a titanium diboride based composite , Ceram. Int., 16, 77-83... 

Multiple fiber fracture prior to failure of composite... 

V.C. Li and C.K.Y. Leung, Steady state and multiple cracking of short random fiber composites , ASCEJ. of Engineering Mechanics. 118,1992, 2246-2264. 

Composite materials have many distinctive characteristics reiative to isotropic materials that render application of linear elastic fracture mechanics difficult. The anisotropy and heterogeneity, both from the standpoint of the fibers versus the matrix, and from the standpoint of multiple laminae of different orientations, are the principal problems. The extension to homogeneous anisotropic materials should be straightfor-wrard because none of the basic principles used in fracture mechanics is then changed. Thus, the approximation of composite materials by homogeneous anisotropic materials is often made. Then, stress-intensity factors for anisotropic materials are calculated by use of complex variable mapping techniques. 

Fig. 8.11 (a) Schematic of the hierarchical structure of a composite with multiple CNT fibers, where each fiber is a composite itself [77]. (b) The intercalation of small amounts of polymer between CNTs during CNT fiber production is a promising method to fabricate structural composites based on nanocarbons [81], With kind permission from Elsevier (2011) and Taylor and Francis (2012). 

In addition to their potential use as structural composites, these macroscopic assemblies of nanocarbons have shown promise as mechanical sensors [83], artificial muscles [84], capacitors [85], electrical wires [59], battery elements [85], dye-sensitized solar cells [86], transparent conductors [87], etc. What stands out is not only the wide range of properties of these type of materials but also the possibility of engineering them to produce such diverse structures, ranging from transparent films to woven fibers. This versatility derives from their hierarchical structure consisting of multiple nano building blocks that are assembled from bottom to top. 

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