Question

QUESTION 23 The data in the table below is for glass fibre-reinforced nylon 6,6 composites. The glass fibre constitutes 42% of the total volume of these composites. Elastic Modulus Tensile Strength (GPa) (MPa) 72.5 3400 Glass fibres Nylon 6,6 3.0 76 If continuous aligned glass fibres are used, what would be the longitudinal stiffness of the composite, in GPa

Answer 1

Ans) We know,

Longitudinal stiffness ($E_L$) = $E_f$ $V_f$ +
E.
$V_m$

where, $E_f$ = Modulus of elasticity of fiber = 72.5 GPa

   = Modulus of elastisity of matrix = 3 GPa

E.

  $V_f$ = Volume fraction of fiber = 42% or 0.42

$V_m$ = Volume fraction of matrix = 1 - 0.42 = 0.58

=> $E_L$ = 72.5(0.42) + 3(0.58)

=> $E_L$ = 32.19 GPa

Hence, longitudinal stiffness of composite is 32.19 GPa