Your guide to composites

What is a composite?

A composite material is made by combining two or more distinct materials to give a unique and better combination of properties. The materials are distinctly different and mechanically separable.

Several different materials used together will produce a part that is stronger, stiffer and that offers characteristics that are better than any single material by itself.

Why choose composites?

Composites are used in many diverse industries from marine to automotive, underground pipes to the monocoque of a Formula 1 car. The main reasons composites are in demand include:

• High strength – Composite materials can be designed to meet specific strength requirements of the application

• Lightweight – Parts can be made both lightweight and strong using composite materials

• Corrosion resistant – Composite products have long-term resistance to chemical and high temperature environments

• Design flexibility – Composite parts can be made into complicated shapes with very little expense

• Durability – Composite parts have a long life span

Composite terms explained

Fibre Reinforced Plastics (FRP) = A polymer matrix reinforced with fibre. A common type of composite material.

Glass Reinforced Plastics (GRP) = A polymer matrix reinforced with fibreglass. GRP resins are typically thermoset, for example a polyester, urethane acrylate, or vinyl ester resin.

Carbon Fibre Reinforced Plastics (CFRP) = A polymer matrix reinforced with carbon fibre.

Markets

Due to their unique properties, composite materials are widely used across the marine, building and construction, renewable energy, automotive, chemical containment, rail, 3D printing, swimming pool and transport markets.

Essential properties of a composite

Combining resin with strong fibre reinforcement creates a composite. Composites are superior to metals in many applications because:

• They have high strength and stiffness combined with low density

• Strength can be restricted to the desired directions – design freedom

• Complex shapes are easy to mould

• They offer high corrosion and environmental resistance

What determines the properties of a composite?

The properties of a composite are determined by:

• The properties of the resin combined with the fibre properties

• Ratio of fibre to resin in the composite

• Geometry and orientation of the fibres in the composite

• How well the resin wets and adheres to the fibres