As composite usage in the aerospace industry increases, it becomes more important to understand the benefits of using them. Let’s discuss what composites are and why they are needed for the future of aerospace.
Over the last few decades, the United States Air Force (USAF) and Navy (USN) have remained undoubtedly the most dominant aerial combat force in the world. One such example is that in 1980s, the US created multiple “4th generation fighters”, advanced fighters for the time that switched from analog to digital processing and were more maneuverable for dogfighting than their predecessors (F-14 to F-18). Unfortunately, the gap is closing. Ten other countries in the world can create aircraft of similar functionality, which forced the United States to create “5th generation fighters” (F-22 and F-35) to remain ahead of competitors. The current generation puts an emphasis on stealth, advanced avionics (millions of lines of code), and higher performance aero structures. Many of these requirements are addressed through the greater incorporation of composite materials.
Composites are conceptually similar to the mixtures addressed in high school chemistry. Like a mixture, a composite contains multiple distinct material “phases”, as in the materials are not compounds. They are not chemically bonded to each other at the atomic level. For composites, the relationship consists of primary matrices (usually polymers/plastics) that contain embedded phases (usually carbon fiber) that serve to reinforce the composite. However, the phases can consist of metal, ceramic, or boron as well depending on the intended use of the part.
The ability to combine materials allows for a myriad of property combinations that would not exist if a singular material type was used. This could be very beneficial due to the number of criteria a part must fulfill to be incorporated into a design (strength, stiffness, ductility, thermal behavior, electrical conductivity, etc.). In the current aerospace market, the composites being used are noticeably effective in the following areas:
- High strength and stiffness relative to weight, which leads to high weight savings. Depending on the component, replacing metal with composites reduces weight from 10-40%.
- Fatigue and corrosion less significant than with traditional metal components.
Due to these benefits, the USAF and USN have gradually increased usage of composites. The F18E/F consisted of about 19% of its weight being carbon fiber composite, which rose to 25% for the F22, and now is estimated to be about 35% for the F35. The greater composite use in the military has inspired higher usage in commercial aerospace as well. The Boeing 787 Dreamliner is around 50% carbon fiber composite with the Airbus A350 XWB being very similar in composition. This manufacturing trend is expected to carry over to another project we are working on: Electric vertical take-off and landing (eVTOL) and urban air mobility (UAM).
PRICE® is dedicated to learning and enhancing our knowledge about composite manufacturing, as both customers and players in the industry are leaning more heavily on this manufacturing technique for future projects. In our follow up blogs we will discuss more research, findings and significant data related to composites.