Composites

Understanding Composites

  • A composite material is composed of at least two materials, which combine to give properties superior to those of the individual constituents.
  • The individual components remain separate and distinct within the finished structure, differentiating them from alloys.
  • The two main categories of constituent parts are the matrix (or binder) and the reinforcement.

Types of Composites

  • Polymer Matrix Composites (PMCs): Also known as fibre-reinforced polymers (FRP), including carbon fibre reinforced polymers (CFRP), and glass reinforced plastics (GRP).
  • Metal Matrix Composites (MMCs): Composites with metal or alloy matrices, such as aluminium.
  • Ceramic Matrix Composites (CMCs): Includes composites of carbon and silicon carbide.

Properties of Composites

  • Composite materials can be designed to be robust yet lightweight, offering significant weight savings for industries such as automotive and aerospace.
  • They can have high strength-to-weight ratios and can be designed for specific mechanical properties.
  • Certain composites are resistant to high temperatures, making them suitable for applications such as fire barriers.
  • Composites can be resistant to wear, corrosion and environmental damage.

Applications of Composites

  • A broad range of industries utilise composites. In automotives and aerospace, they can reduce weight and increase fuel efficiency.
  • In construction, composites can be used in panels, beams, and in structural components.
  • In sporting goods, they provide light-weight strength for items such as golf clubs, bicycle parts and fishing rods.
  • Composites can also be found in everything from bathroom fixtures to wind turbine blades.

Environmental Impact of Composites

  • Some forms of composites, such as carbon fibre, can be difficult to recycle, causing environmental concerns.
  • However, many composites can be effectively recycled and manufacturers are increasingly focussing on reducing environmental impact.
  • Life cycle assessment (LCA) can be used to minimise the environmental footprint of composite manufacture and use.

Manufacturing Techniques

  • Composite manufacturing processes include hand layup, automated fibre placement, resin transfer moulding, and pultrusion.
  • Composites can be fabricated into final shape, or can be made into stock forms (like sheet or beam) for later fabrication.
  • Techniques for joining composites include adhesive bonding, mechanical fastening, and welding.