Fibre reinforced polymer composites reinforcing fibres stress-strain

Figure 6.8 The flexural stress versus strain curves for glass fibre-reinforced CTPEGA-modified epoxy-based composites (containing 0-40 phr of CTPEGA) Reprinted with permission from D. Ratna, T.K. Chongdar and B.C. Ghakrahorty, Polymer Composites, 2004,25,165. 2004, John Wiley and Sons Publishers...

Licea-Claverie and co-workers [57] studied mechanical stress-strain, impact properties and also thermal properties of PA 6,6 (including some recycled PA) with mixed glass fibre and carbon fibre reinforcements and compared these properties with those of the virgin polymers. No dependence on mechanical properties because of increasing amounts of scrap in the composites was found up to 10.4 wt%. The recycled composites generally showed lower mechanical properties when compared with the virgin composites because of a poor matrix-fibre adhesion. 

Shehata, I.A.E.M., Carneiro, L.A.V., and Shehata, L.C.D. (2002), Strength of short concrete columns confined with CFRP sheets . Mater. Struct., 35, 50-58 Teng, J.G., Huang, Y.L., Lam, L., and Ye, L.P. (2007), Theoretical model for fiber reinforced polymer-confined concrete , J. Comp. Const., 11(2), 201-210 Toutanji, H. A. (1999), Stress-strain characteristics of concrete columns externally confined with advanced fiber composite sheets , ACI Mater. J., 96(3), 397 04 van Erp, G.M., Heldt, T.J., Cattell, C.L., and Marsh, R. (2002), A new approach to fibre composite bridge structures , 17th Australasian Conference on the Mechanics of Structures and Materials, ACMSM17, Gold Coast, Queensland, Australia, 12-14, 2002. pp. 37 5... 

The ultimate strength of a composite of fibre and polymer is basically dependent upon the stress-strain relationship of its components. Any fibre whose strength and modulus of elasticity is greater than a polymer is capable of theoretically providing reinforcement to that polymer. Practically, however, the difference in properties has to be considerable to obtain efficient reinforcement and the effectiveness of the reinforcement is dependent upon the degree of adhesion which can be achieved. Other factors which also influence the properties of a composite are relative volumes of reinforcement and matrix, their physical and chemical properties, the temperature resistance and, of very considerable importance, the fibre length which is being used. 

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