There are many factors/tradeoffs that affect the decision to use
composite material. Advanced composite material is indeed used in
critical load bearing structures but for items such as Landing gear,
you have to the environment and maintainability. Aircraft Landing
Gear are subject to very harsh environments (debris from tires,
runways, harsh fluids, and so on).
Carbon fiber is a very good substitute for traditional metal
structures, but that does not mean it's right for every job. The
strength of a fiber reinforced product is based on the continuity and
orientation of the fiber whereas metal has more uniform strength
characteristics. The bearing loads on landing gear coming in high
impact waves from many directions and the fiber must be capable of
distributing those loads without failure. Theoretically it can
probably be done, but it is not practical.
If you look at the modern commercial aircraft today, everything minus
the fuselage pressure vessal is composite material (fairings, Flaps,
Doors, Elevators, Rudders, Radomes, etc). In addition, there are
other private and military aircraft that use composite material as
primary structures (i.e. wings). Some aircraft are made entirely from
composite material - except the engines and landing gear.
Of course, when you say composite, that leaves your question open to
the whole field of material used in "composite" products (theromsets,
thermoplastics, metal matrix, glass reinfonced, carbon fiber, kevlar,
core material, resin systems, and so on). |
