a. In a fibre-reinforced composite, what is the role of the matrix, the fibre and the fibre-matrix interface?

b. Explain briefly how the volume of fibre, fibre orientation, and fibre strength and modulus affects the properties of fibre-reinforced composites.

c. Explain why bonding between carbon fibres and an epoxy matrix should be strong, whereas bonding between silicon nitride fibres and a silicon carbide matrix should be weak.

d. 5 kg of continuous E-glass fibres are introduced in a unidirectional orientation into 6 kg of a Polypropylene (PP) matrix. The properties of glass fibre and Polypropylene matrix are given in the Table Q2(d)

 

Calculate

• the density of the composite,
• the modulus of elasticity of composite parallel to the fibres, and
•  the tensile strength of composite parallel to the fibres.

Table Q2(d)

 

Material	Density      (g/ccm)	Tensile strength             (MPa)	E- Modulus          (GPa)
Glass Fibre	2.6	2100	8.0
PP	1.21	42	3.6