A polymer matrix composite consists of polyester reinforced

A polymer matrix composite consists of polyester reinforced with Kevlar-29 fibers. The volume fractions of polyester and Kevlar are 60% and 40%, respectively. The Kevlar fibers have a modulus of elasticity = 60 GPa in the longitudinal direction and 3 GPa in the transverse direction. The polyester matrix has a modulus of elasticity = 5.6 GPa in both directions, (a) Determine the modulus of elasticity for the composite in the (a) longitudinal direction and (b) transverse direction.

Solution

Modulus of elasticity for composite:

E_Composite= E_fiber* V_fiber + E_matrix* V_matrix ....(1)

From eq\'n 1.... for transverse direction:

E_{composite, transverse}= E_f,t * V_f,t + E_m,t * V_m,t

= 3 * (0.4) + 5.6 * (0.6)

=4.56 GPa

E_{composite, longitudinal} = E_f,l *V_f,l + Em,l * V_m,l

   = 60 * (0.4) + 5.6 * (0.6)

= 27.36GPa