Answer
Ecl = 59.7 GPa (86.6 x 105 psi)
Work Step by Step
Use the following expression:
$E_{cl}$ = $E_{m}$$V_{m}$ + $E_{f1}$$V_{f1}$ + $E_{f2}$$V_{f2}$
From Table 16.4 (page 652), the elastic moduli of aramid and glass fibers are 131 GPa (19 × 106 psi) and 72.5 GPa (10.5 × 106 psi), respectively. Substituting these values in the above expression:
$E_{cl}$ = (4.0 GPa)(1.0 - 0.25 - 0.35) + (131 GPa)(0.25) + (72.5 GPa)(0.35)
$E_{cl}$ = 59.7 GPa (86.6 x $10^{5}$ psi)
