MAE4426 Week 1

What is the primary role of the matrix in a fibre-reinforced composite?

• Provide electrical conductivity

• Provide tensile strength

• Hold the fibres together and protect them

• Increase weight

Which of the following is a major advantage of using composites in aircraft?

• Low cost

• High strength-to-weight ratio

• High electrical resistance

• Easy to recycle

Which fibre is most commonly used in aerospace structures?

• Glass fibre

• Natural fibre

• Nylon fibre

• Carbon fibre

What kind of polymer matrix becomes rigid after curing and cannot be re-melted?

• Thermoplastic

• Thermoset

• Polyurethane

• Elastomer

Which statement best explains why continuous fibres are preferred in structural composite parts?

• They improve recyclability

• They increase thermal conductivity

• They reduce manufacturing time

• They maximise strength and stiffness in the load direction

What is one major operational limitation of composite materials in service?

• High thermal expansion

• Poor corrosion resistance

• Susceptibility to hygrothermal damage

• High through-thickness strength

What is the most likely failure mode of composites under low-energy impact (e.g., bird strike)?

• Surface corrosion

• Internal delamination

• Elastic deformation

• Melting of the matrix

Why is midplane symmetry used in laminate design?

• To reduce cost

• To balance thermal stresses and avoid warping

• To increase fibre volume fraction

• To enhance electrical conductivity

Why must through-thickness loading be avoided in composite design?

• Because they have low through-thickness strength

• Because it affects colour uniformity

• Because it increases ductility

• Because composites are anisotropic

What is the key assumption in the mechanics of materials approach for predicting composite properties?

• Random fibre distribution

• Perfect fibre-matrix bonding

• Nonlinear fibre behaviour

• Temperature-independent matrix properties