A continuous and aligned glass fiber-reinforced composite consists of 35 % volume of glass fibers with a modulus of elasticity of 70 GPa and a polyester resin that, when hardened, displays a modulus of 4 GPa. What will be the modulus of elasticity of this composite material in longitudinal direction?

Given that

Elastic modulus of fiber, Ef=70 GPa,

Elastic modulus of matrix, Em=4 GPa,

Volume fraction of fibers, Vf=35%=0.35

Volume fraction of matrix, Vm=1-Vf=1-0.35=0.65

Using Rule of Mixture, the elastic modulus (Ec) of composite in longitudinal loading is given as

Ec=EfVf+EmVm

Substituting the corresponding values in above formula, we get

Ec=70×0.35+4×0.65

Ec=27.1 GPa