Opposites Attract: The Strength of Composite Materials

Scientists and engineers are always striving to save weight, energy and space. The most radical breakthrough in recent times is the use of composite materials. Composites such as carbon fibre have been used for years by Formula 1 racing teams, however recently, they have become reliable enough to use in commercial aircraft such as the Boeing 787 and Airbus A350.

Simply put, a composite is a mixture of a strong, light, expensive material (fibre) with a less expensive, heavier, weak material (matrix). Blending these together makes a much stronger composite material which is strong, medium weight, and much less expensive. Changing the ratios of these materials allows us to tune the properties of the composite to tailor to our needs. The key to all this is to get a good bond to transfer the stress to the stronger fibre material.

Think of it in the same way as coffee relieves your stress, you have a strong bond. However something you don’t enjoy quite so much (eg. sitting in traffic) doesn’t have the same effect!

What if we wanted to save energy in a fridge or your central heating system, what use does a Formula 1 car have? Well, carbon is widely known to have excellent thermal properties. So adding this to our poorly conducting fluid should help. Thus, applying our earlier ratio logic we should get the same outcome. Well yes and no! Again it comes back to the interface between the two materials. Energy must be transferred from the fluid to the dispersed carbon, and that’s not easy to master. 

Our world is becoming more power hungry and demanding ever faster and ever smaller devices. Automotive companies want smaller, lighter and more powerful engines. Computer chips are smaller, faster and produce more heat. All this energy needs to be dissipated by smaller and more efficient radiators, giving the scientists and engineers a challenge. How to move growing quantities of heat energy in shrinking systems and increase the efficiency of the process? Is the answer is the carbon composite fluid?

This guest post was written by Peter Marshall, a PhD student in Mechanical and Aerospace Engineering at Queen's University, Belfast. Image via Wikipedia .