Fiberglass, carbon fiber, and aramid fibers are the mainstays of aircraft composite technologies. They have served the aerospace industry well for decades. Yet in the push to reduce dependence on fossil fuels, engineers are now working on bio-based composites. Developing them for aerospace means overcoming some inherent challenges.
Also known as bio-composites, these materials show a lot of promise. But they are not quite ready for prime time in aerospace applications. So what are the big challenges? Let us take a look.
Materials like carbon fiber and fiberglass play such a significant role in aerospace because their performance is superior to aluminum and steel for certain applications. Bio-composites aren’t quite there yet in terms of performance. For example, they are more moisture sensitive. Most bio composites do not offer the level of moisture resistance we need.
Bio-composites do better in terms of thermal and mechanical stability, but they still lag carbon fiber in both thermal resistance and impact tolerance. There is also the question of fiber matrix compatibility. Achieving the strongest possible adhesion between natural fibers has proved difficult.
Manufacturing aircraft composite technologies with traditional fibers is reliable and consistent. Decades of process refining have seen to that. As far as bio-composites are concerned, the industry continues to struggle. Both consistency and scalability will eventually be achieved. The industry just needs time to develop more uniform processes.
Manufacturers have also struggled to develop bio-composites with sufficient strength to be utilized in load bearing components. So for now, any bio-composites that may be used in aerospace are limited to nonstructural components, like cabin panels.
Underpinning all of it are the financial challenges that come with bio-composites. First and foremost, the materials needed to manufacture them are more expensive than their fossil fuel counterparts are . A big part of the expense is the amount of energy consumed by material processing.
Given the prohibitive cost and nature of both materials and processing, going all-in on bio-composites requires significant capital investment. Additional investments are necessary in retooling production lines and obtaining the required certifications.
Recycling is one of the goals of transitioning away from fossil fuel composite in favor of bio-based alternatives. But recycling bio-composites is not as simple as it sounds. The strong bonds between fibers and matrices make recycling difficult and expensive.
The added expenses that come with bio-composites create market challenges for both manufacturers and buyers. Simply put, the market isn’t yet ready for widespread adoption of bio-composites for just about any application – let alone aerospace.
None of this is to say that bio-based composites will never be a normal part of aircraft composite technologies. It’s quite possible that they will all but replace fossil fuel-based composites a couple of decades from now. It is a matter of following the right path forward.
That path involves new processing techniques capable of improving production efficiency. Improve efficiency and you bring the cost down. Alongside more efficient production are more investments in research and development. The faster we develop bio-composites capable of withstanding the stresses of load bearing applications, the more attractive they will be.
An intermediate phase between current technologies and all bio-based composites could be hybrid materials that combine natural fibers with synthetic reinforcements. Hybrids would at least cut down the volume of fossil fuel-based fibers the industry now relies on.
Will bio-based aircraft composite technologies ever be the norm? We are headed in that direction. But for now, aerospace composites are rooted in fossil fuels. Carbon fiber, fiberglass, and aramid fibers are getting the job done.
