There was an interesting editorial in the May 2023 edition of Composites World Magazine. The point of the article is that while composites used to be used as replacements for more traditional materials, now for a number of applications and even entire industries, they are the mainstream material of choice.
This has happened only over the course of the last 5 to 10 years, but it is now a permanent change to the landscape of materials that are available to a part or system designer or applications engineer. And there are several industries and burgeoning applications that demand the use of composites because there is no other solution that will meet all of the requirements for that industry.
The editorial describes four applications that cannot exist without composites:
1. Urban Air Mobility – this space has already gotten a few entrants that are working on getting FAA certification for their vehicles. First of course is the drone delivery service that Amazon and others have been experimenting with. But there is another sector of this space that is evidenced by Joby Aviation – the Urban Air Taxi.
They have a prototype that is nearing FAA certification for use in urban areas that cannot exist without having an all composite airframe and body structure. Composites are the only materials that have the strength, stiffness and light weight (specific strength, specific stiffness to be technical about it) that make an air taxi possible. These are all electric aircraft and need to have quite a bit of range between charges to be feasibly used commercially. Joby’s website says that they will have their FAA certification by 2025, so expect to see some of these in a city near you sometime in the next few years.
2. Hydrogen Storage – Storing enough hydrogen to make a difference requires that the hydrogen be stored as a liquid, which of course means cryogenic temperatures. Most
metals become brittle at these temperatures and really can’t be used for storing liquid hydrogen. Carbon fiber composites do not become brittle and can safely store liquid hydrogen at cryogenic temperatures. And these tanks can be loaded onto rail cars or tanker
trucks for delivery from where the hydrogen is liquified to where it needs to be used. The hydrogen economy is booming right now, and the Department of Energy plus a number of other organizations have been working feverishly to develop carbon fiber pressure vessels with a polymer liner rather than a metallic liner for transportation and storage of liquid hydrogen (pictured above). The development of these cylinders in sizes ranging from what you could reasonably put in the back of a pickup to a tank mounted on a rail car, these all composite cryogenic pressure vessels are already in production and being readied for the coming hydrogen revolution.
3. Wind Turbine Blades – I have of course talked about wind turbines quite a bit in this newsletter, so it was interesting to see in the Composites World editorial them using this as an example of an application that can only be successful if the blade itself is all composite.
And with the advent of the newer and larger wind turbines, these blades are most if not all carbon fiber. Carbon fiber composites are the only material available today that is capable of withstanding the forces required while still being light enough that they work well even in fairly mild winds. And, as I have said many times, wind turbine blades are the single highest tonnage application of carbon fiber composites today. This has of course been enabled by the reductions in cost and the scaling up of the process for producing carbon fiber. We now have several manufacturers of carbon fiber that are capable of production of tons of fiber each month for application to the industries that need them.
4. Aerospace and Space –
With the advent of the Boeing 787 and the Airbus A350, as well as the Stratolaunch, and the Scaled Composites Proteus (pictured above), the aerospace industry has gone from the idea of whether or not to use composites to which fiber and resin system and composites manufacturing process they are going to use to make their aircraft. In addition to the commercial aircraft, even the private and short hop aircraft have adopted composites as mainstream and necessary. No longer a replacement for what would have been a metallic part, most new aircraft being designed today are designed around monocoque composite airframes. The aerospace industry, both in spacecraft and in aircraft, have completely separated from the past and the new designs are clean sheet of paper designs using composites as the main structural materials.
These are the four industries / applications that have gone completely mainstream in their use of composites according to Composites World. I want to add one more that is coming and is not too far away from being realized – the automotive and truck industry. Every major automotive company has adopted the use of composites for non-primary structure, and most of them have at least experimented with use of composites for primary structure as well. And, now with the advent of battery electric cars, there is less of a need for a ladder frame made out of steel which has been the standard of the automotive industry since the days of Henry Ford. Since the batteries are typically in a tray at the bottom of the vehicle since they are heavy and flat, that tray could very easily become the foundation of a monocoque frame entirely made out of composites that would be stronger, stiffer, and much lighter weight than its steel counterpart. All of the automotive manufacturers if they have not already built prototypes of all composite electric vehicle frames have at least started conceptual design work on them. And, with the new California environmental regulations going into force in the next 10 years or so, expect to see the major auto manufacturers begin to introduce models of at least their higher end (high profit margin) vehicles with all composite frames.
So, as you can see, composites have gone mainstream, and several industries would not exist today without having started with a clean sheet of paper design (from the ground up is another way of putting it) using composites rather than just replacing metal components with composites.
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