Bigger, Taller Stronger: Realising the Potential of Carbon Fibre – Why Carbon Fibre?

Carbon fibre-reinforced polymers (CFRPs, or simply ‘carbon fibre’) have become the material of choice where high strength-to-weight ratios and rigidity are demanded. Here are the reasons why carbon fibre-reinforced polymers (CFRPs, or simply ‘carbon fibre’) have become the material of choice.

Carbon fibres are like chicken mesh

The structure of carbon in fibre depends on the manufacturing process, but the common theme is the hexagonal mesh of carbon atoms. At an atomic level, it looks like chicken mesh. Because the binding strength between carbon atoms is exceptionally high, carbon lattices are an order of magnitude stronger than metals or glasses. However, they’re generally produced in small lengths (1/100 of a mm, though half a metre has been achieved), so they’re woven together in a similar way that cotton fibres get spun into cotton thread, with each strand providing support to its neighbours. In that way, long, strong fibres are made, which can then be woven into tough sheets.

Directional strength

The sheets and weaves possible with carbon fibre also mean that it can be engineered to have a directional strength that’s otherwise not possible with isotropic (i.e. the same in every direction) materials like traditional concrete or solid metal beams. It’s the difference between designing in a solid metal bar and an I-beam: an I-beam has a superior bend and shear performance than a solid. Likewise, a 2014 study in Procedia Materials Science showed that carbon fibre has better tensile and flexural strength than fibreglass, making it a superior material for pull and twisting stresses.

In high-demand situations where you need a stiffer, lighter product, carbon fibre delivers better lifetime performance than fibreglass thanks to its structure.

Excellent strength and stiffness-to- weight ratios

Composites like carbon fibre are relatively light for their strength. The relative lightness means carbon fibre composites can be crafted into shapes that are inherently stiffer and stronger than steel or aluminium, while weighing a fraction of its metal counterparts. This is one reason why carbon fibres are used in conjunction with metals in high- performance aerospace and vehicle design.

Carbon fibre’s strength as a material comes down to the nature of the composite. The ability to tailor the direction of the carbon fibres means it can yield stiffness 20 times, and strength four times, greater than a metal baseline. That means carbon fibre structures can span further distances and support greater weights while also weighing less – opening doors for greater designs.

Complex shapes and part consolidation

Composites like carbon fibre can be made into highly complex shapes, making it possible to use a single piece made from composite to replace an entire assembly of metal parts. This is because composites are formed when the matrix (the resin) solidifies. Carbon fibre can be shaped into plane wings or watch parts before it cures, with no major milling or shaping after the fact, reducing manufacture time and creating a lighter product.

Rather than manufacture and fix together smaller parts, CFRPs make it possible to have a single continuous complex part manufactured from one composite material. While it’s also possible to cast metals into complex shapes, carbon fibre can be shaped significantly below the melting points of steel or aluminium,
and with less material. Now, a huge range of designs, textures and finishes are possible with CFRPs for any purpose.

Lighter, more durable, longer lasting and with a higher stiffness-to-weight ratio, it’s easy to see why carbon fibre is making its way into the construction industry, where taller, bigger projects put higher demands on traditional building materials like steel, concrete and timber. Download our full ebook to learn more about the benefits of carbon fibre-reinforced polymers.

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