Carbon Fiber, Fiberglass, and Kevlar for Different Applications
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Carbon fiber, fiberglass, and Kevlar (aramid fibers) are all utilized as industrial composites. Each category has its own properties that can be advantageous to certain types of industrial applications. Therefore, there is no one-size-fits-all composite that meets every need.
For the industrial user, it is a matter of analyzing the various properties before determining the most appropriate material. Though this post will provide a basic overview, any thorough comparison involves a lot more information than we can offer in a single blog post. Needless to say, comparing the three types of composites requires knowledge and time.
A Basic Description
The three categories of composites we started this post with all combine fibers with some sort of resin or ceramic matrix. The fibers give the finished material its strength. Here is a basic definition for each one:
CarbonFiber – Fibers made from joining chains of carbon molecules are combined with a resin matrix to create what is known as a carbon fiber reinforced plastic (CFRP). These plastics are lightweight, stiff, and strong. However, they are also brittle and expensive.
Fiberglass – The material we know as fiberglass combines small glass fibers with a resin matrix to create a cost-efficient, chemical-resistant, and easy-to-process material. It is the least expensive of the three.
Kevlar – Kevlar is a proprietary composite combining aramid fibers with a resin or ceramic matrix. It is exceptionally resistant to impact. It also offers toughness and thermal stability. Of the three, Kevlar is considered the most ‘high-end’, if you will.
Most consumers have at least some experience with carbon fiber and fiberglass. The two materials are common enough to be found in just about every home. Kevlar is another matter. It is usually the domain of law enforcement, the military, pro sports, and other high-impact environments.
Stressing the Most Important Properties
Working with industrial composites gives engineers and manufacturers lots of options. Within the three categories, composite materials can be custom designed to stress the most important properties for a given application. But before a composite can be modified, the right material needs to be chosen.
Here are just some of the things engineers need to consider:
Strength and Weight – A material’s strength-to-weight ratio can make a difference from a design standpoint. Carbon fiber excels in this particular area, making it ideal for aircraft fuselages and panels. Kevlar also offers a high strength-to-weight ratio.
Stiffness – Carbon fiber also wins the day when it comes to material stiffness. It is up to two times stiffer than Kevlar and five times more stiff than fiberglass.
Density – When an industrial application requires a dense material, fiberglass is superior. It is more dense and heavier than both of the other two materials. Kevlar is the lightest. Carbon fiber is also lightweight, and its density is comparatively low.
ThermalResistance – Many industrial applications require a certain amount of thermal resistance. Kevlar offers the most of all three, followed by carbon fiber and fiberglass.
ImpactResistance – Kevlar is also the best of the three in terms of impact resistance. That’s why it is so popular in military and law enforcement applications. Fiberglass offers good impact resistance and flexibility, while carbon fiber is more brittle and subject to impact failure.
Other things engineers need to look at include chemical resistance, UV resistance, electrical conductivity, ease of processing, and even fatigue resistance. There is a lot that goes into determining the right composite for an industrial application.
