Ahh, carbon fibre… Is there a day in the automotive world where you don’t hear about it? It used to be a highly-prized composite back in the late 70’s early 80’s. At that time, it was akin to having aerospace technology in your car. Now? You would be hard-pressed not to find it in your car, even if you drive a Prius!
We want to talk about carbon fibre, in a 5 part series, to help you better understand why it’s used, the different types, and ways for you to get involved and make some DIY carbon parts!
As you know we sell Carbon Fibre in our store. We often get emails about carbon fibre and what applications is can be used in. We hope this quick guide will help you better understand when it’s good to use carbon fibre, and maybe when it’s better to go with an alternative.
Let’s Get Stiff…
Carbon Fibre has lots of great properties, it’s corrosion resistant, electrical conductive. resists fatigue, it has good tensile strength, it’s fire resistant, low coefficient of thermal expansion (this one is important in our DIY section), and is inert. But it’s real claim to fame is that it’s lightweight, strong, and stiff!
What does that mean? Well if you want to dive deep down into the physical definitions of it, we urge you to check out this great article by Christine DeMarchant, who talks about all its properties. In a nutshell, carbon fibre is lightweight when compared to other materials such as aluminium or steel, which also have similar strengths. This, in addition to the fact that carbon fibre does not like to bend along its fibres (its stiffness), lends to what is called its specific strength. It has a high one at that, clocking in at 2457 kN.m/kg vs 254 kN.m/kg for steel.
If you’ve never seen how they test for this, it’s pretty cool; they place a sample on an Instron machine (which is kind of like the Hydraulic Press, but way more scientific) and it presses down on the sample until it yields.
The point of all this? It all boils down to the application it’s being used for. Generally speakings, we see carbon parts used as the chassis (think of the Formula 1 monocoque chassis, or the McLaren chassis for their road cars) where stiffness matters. Other uses, such as aerodynamic elements, are good places, because they too see lots of vibrational force and high pulling forces which carbon excels at handling.
We are also starting to see carbon fibre used on wheels, which is really quite a feat of engineering. Lowering the unsprung weight and rotational mass is truly a big step forward for cars in general.
Where is it not useful? Well, as I mentioned in the beginning of the article, you’re starting to see carbon fibre everywhere: trim pieces, as roof panels, hoods, and other body panels. These parts might be suited better with a lightweight s-glass (different from your typical e-glass fibres), especially since they typically have low forces exerted on them. In addition, these fibreglass parts would be cheaper to replace.
We will dive more into different fabrics, and the types of carbon fibre that you can purchase in Part 2.