What are composites?
Materials made by combining two or more different materials to improve performance by exploiting the best properties of each.
In which industries are composites widely used?
Aerospace, automotive, sports, and construction.
What is a composite material formed from?
A matrix (binder) and a reinforcement (fibre or particle).
What is the matrix in a composite material?
The binding material that surrounds and supports the reinforcement.
What is the reinforcement in a composite material?
Material (fibres or particles) that adds strength to the composite.
What is an example of a composite material?
Glass-reinforced plastic (GRP) with polyester resin as the matrix and glass fibres as the reinforcement.
What are the properties of GRP?
Tough, corrosion-resistant, lightweight, good strength.
What are the uses of GRP?
Boats, car body panels, water tanks.
What are the properties of CFRP?
Extremely strong and lightweight, corrosion-resistant.
What are the uses of CFRP?
Aerospace, bike frames, tennis rackets.
What is reinforced concrete made from?
Concrete and steel rods.
What is plywood made from?
Veneers of timber glued in alternate grains.
What are the properties of plywood?
Strong, stable, less warping, good strength:weight ratio.
What is MDF made from?
Wood fibres and resin, compressed.
What are the advantages of composites?
- Tailored performance
- High strength-to-weight ratio
- Corrosion and chemical resistance
- Dimensional stability
- Good durability and impact resistance
What are the limitations of composites?
- Often expensive to manufacture
- Difficult to recycle or repair
- May require special tools and skills
- Can be brittle
What is the lay-up method used for?
GRP and CFRP, where fibres are placed in a mould and resin is added.
What is pultrusion used for?
Long composite sections like rods and beams.
What is vacuum bagging used for?
CFRP and aerospace parts, where layers are compressed with vacuum pressure.
What are environmental considerations regarding composites?
- Difficult to recycle
- Often use non-renewable resources
- Some contain toxic resins or adhesives
What is the definition of fibre orientation?
Direction fibres are laid, affecting strength and flexibility.
What is laminating?
Bonding layers together, such as in plywood or GRP lay-up.
True or False: Composites are generally easier to recycle than traditional materials.
False
What should you compare when answering exam questions about composites?
Compare composites (e.g., CFRP) to metals (e.g., aluminium) considering weight, strength, cost, workability, and environmental impact.
