Question

A uniaxial continuous fibre composite consisting of 40 vol% fibres (Ef = 160 GPa) in a matrix (Em = 35 GPa). Which of the following change can maintain the Young's modulus of the composite parallel to the fibre direction (EL = VfEf + (1-Vf) Em)? (A) Keep the same Young's modulus of matrix (Em), but use 50 vol% of a different type of fibres with Ef1 = 120 GPa. (B) Keep the same Young's modulus of fibres (Ef), but decrease fibre fraction to 25 vol% and use a different matrix with Em1 = 60 GPa. (C) Keep the same Young's modulus of matrix (Em), but use 30 vol% of a different type of fibres with Ef2 = 180 GPa. (D) Keep the same Young's modulus of fibres (Ef), but increase fibre fraction to 45 vol% and use a different matrix with Em2 = 15 GPa. (E) Keep the same Young's modulus of matrix (Em), but use 20 vol% of a different type of fibres with Ef3 = 220 GPa.

          A uniaxial continuous fibre composite consisting of 40 vol% fibres (Ef = 160 GPa) in a matrix
(Em = 35 GPa). Which of the following change can maintain the Young's modulus of the
composite parallel to the fibre direction (EL = VfEf + (1-Vf) Em)?
(A) Keep the same Young's modulus of matrix (Em), but use 50 vol% of a different type
of fibres with Ef1 = 120 GPa.
(B) Keep the same Young's modulus of fibres (Ef), but decrease fibre fraction to 25
vol% and use a different matrix with Em1 = 60 GPa.
(C) Keep the same Young's modulus of matrix (Em), but use 30 vol% of a different type
of fibres with Ef2 = 180 GPa.
(D) Keep the same Young's modulus of fibres (Ef), but increase fibre fraction to 45
vol% and use a different matrix with Em2 = 15 GPa.
(E) Keep the same Young's modulus of matrix (Em), but use 20 vol% of a different type
of fibres with Ef3 = 220 GPa.

$A uniaxial continuous fibre composite consisting of 40 vol% fibres (Ef = 160 GPa) in a matrix (Em = 35 GPa). Which of the following change can maintain the Young's modulus of the composite parallel to the fibre direction (EL = VfEf + (1-Vf) Em)? (A) Keep the same Young's modulus of matrix (Em), but use 50 vol% of a different type of fibres with Ef1 = 120 GPa. (B) Keep the same Young's modulus of fibres (Ef), but decrease fibre fraction to 25 vol% and use a different matrix with Em1 = 60 GPa. (C) Keep the same Young's modulus of matrix (Em), but use 30 vol% of a different type of fibres with Ef2 = 180 GPa. (D) Keep the same Young's modulus of fibres (Ef), but increase fibre fraction to 45 vol% and use a different matrix with Em2 = 15 GPa. (E) Keep the same Young's modulus of matrix (Em), but use 20 vol% of a different type of fibres with Ef3 = 220 GPa.$

Added by Jose Ramon G.

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