A2 [2 Marks] A unidirectional fiber composite consists of glass fibers (E) in a matrix of epoxy. a) Find the minimum fib

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A2 2 Marks A Unidirectional Fiber Composite Consists Of Glass Fibers E In A Matrix Of Epoxy A Find The Minimum Fib 1 (157.67 KiB) Viewed 20 times

A2 [2 Marks] A unidirectional fiber composite consists of glass fibers (E) in a matrix of epoxy. a) Find the minimum fiber volume, in order to enhance the strength of epoxy. b) If short glass fiber is used with volume fraction of 30%, determine the critical fiber length to avoid fiber pull-out during breakage failure. Assume that the fiber diameter is 12 µm. Use the moduli given in Table, and use an average value where a range of moduli is given. The shear strength of epoxy is 25 MNm². The elongation at break (fracture strain) is 3% for E-glass, and 11% for epoxy. PROPERTIES OF SOME FIBRES AND MATRICES Modulus Strength Material Density p(Mg m-³) E (GPa) σf (MPa) Fibres Carbon, Type 1 1.95 390 2200 Carbon, Type 2 1.75 250 2700 Cellulose fibres 1.61 60 1200 2.56 76 Glass (E-glass) Kevlar 1400-2500 2760 1.45 125 Matrices Epoxies 1.2-1.4 2.1-5.5 40-85 Polyesters 1.1-1.4 1.3-4.5 45-85