AATCC News

 
Back to Contents March 17, 2015
 

Engineering Parameters for Aerospace Textiles

 

By Nicola Davies

 

The wings and fuselage of the plane with which the Wright brothers achieved the first powered flight used plain woven cotton (muslin), stretched over a wooden frame. Textiles have continued to play a vital—and continually evolving—role in aeronautics since those pioneering efforts over a hundred years ago. In fact, textiles are key engineering components of today's fighter jets, commercial airliners, private planes, rockets, space-shuttles, and helicopters.

There are obvious applications, such as seat covers, parachutes, safety belts, floor coverings, evacuation slides, and space suits. However, bulkheads and other interior structural elements are also often provided by textile reinforced composites. Furthermore, textiles continue to play a key role in core aerospace applications, including: helicopter rotor blades; brake linings; composite fire barriers; engine cowls; gaskets and seals; filament-wound pressurized oxygen tanks; rocket nozzles; and, landing gear doors.

 

Dimensional Stability—Stiffness to Weight Ratio

 

Professor Aravin Periyasamy, textile technologies researcher and scholar, believes the greatest area of need for advancements in aerospace textiles and fabrics is simply the "production of lightweight space vehicles." This is one of the primary objectives of structural textiles—not just for space travel, but for commercial airliners, helicopters and all other aerospace applications—a favorable ratio of stiffness to weight. "Stiffness" must be distinguished from "strength." For example, steel's strength to weight ratio is higher than that of aluminum, but its stiffness to weight ratio is lower. Steel is more elastic.

While using thin steel for a stronger and lighter aileron than one made of aluminum would indeed result in an aileron that wouldn't be likely to tear or break, it also has its drawbacks. For one, it would bend under stress more easily than an aluminum aileron of equal weight, defeating some or all of the intended aerodynamic effect, and resulting in poor control of the aircraft.

Composites such as carbon-fiber, glass-fiber, alumina-fiber, boron-fiber, silicon-carbide-fiber, graphite-fiber and aramid-fiber reinforced polymers have higher ratios of stiffness to density than metals and other materials.

 

Stability Under Temperature Extremes

 

Fire protection is important for some aerospace textile functions, but dimensional stability in the face of extreme temperatures is particularly crucial. A moving part that changes size or shape with temperature won’t continue to function adequately. Textiles are also used for gaskets and other applications where dimensional stability is essential to maintaining a seal.

Textiles used on the exterior of space-faring craft need to accommodate very low temperatures (approaching zero degrees when the craft is in open space), as well as potential extremes of high temperature. Certain parts of airplanes are also subject to wide temperature variations. Resistance to temperature extremes is especially important if the space craft are designed to re-enter the earth's or another planet's atmosphere at a high velocity. Indeed, a textile-based composite, Nomex, is used to protect the entire space craft and occupants from this heat extreme.

Polybenzimidazole and alumina-boria-silica textile composites are among other fiber-reinforced polymers with excellent temperature-related parameters. 3M Nextel Aerospace fabrics, for example, maintain integrity at temperatures up to 2000°F.  

Other valuable qualities for aerospace textiles include low electrical conductivity, sound insulation, thermal insulation, and corrosion resistance.

The engineering parameters for aerospace textiles comprises a vital consideration of dimensional stability, with a specific focus on stiffness to weight ratio and stability under temperature extremes. However, the role of textiles within aeronautics continues to evolve and it will be interesting to see how new innovations will contribute to aerospace engineering.