1. This report includes the research on the materials used in the manufacturing of Boeing 787
Dreamliner. It also includes the pros of using composites in the structural parts of the aircraft.
BOEING 787 - REPORT
MATERIALS USED IN 787 AIRCRAFT
2. 1
BOEING 787 -
REPORT
MATERIALS USED IN 787
AIRCRAFT
The newest Dreamliner Boeing 787 makes greater use of composite materials
in its airframe and primary structure than any previous Boeing commercial
airplane. The airframe comprising nearly half carbon fiber reinforced plastic
and other composites. This approach offers weight savings on average 20 %
compared to more conventional Al designs.
Every aircraft designed today and tomorrow will be a mixture of both metals
and composites. It’s all about putting the right material in the right place. For
example: Al is sensitive to tension loads but handles compression very well.
On the other hand, composites are not as effective in dealing with
compression loads but are excellent at handling tensions. The expanded use
of composites, especially in the highly tension-loaded environment of the
fuselage, greatly reduces maintenance due to fatigue when compared with an
Al structure.
This type of analysis has resulted in the increased use of titanium as well.
Where loading indicates metal is a preferred material system but
environmental considerations indicate Al is a poor choice, Ti is an excellent
low-maintenance design solution. Ti can withstand comparable loads better
than Al, has minimal fatigue concerns, and is highly corrosion resistant. Ti use
has been expanded on the 787 to roughly 14 % of the total airframe.
The experience with the Boeing 777 proves that composite structures require
less scheduled maintenance than non-composite structures. For example, the
777 composite tail is 25 percent larger than the 767’s aluminum tail, yet
requires 35 percent fewer scheduled maintenance labor hours. This labor hour
reduction is due to the result of a reduced risk of corrosion and fatigue of
composites compared with metal.
Corrosion and fatigue in a structure add significantly to the non-routine
maintenance burden on an operator. Non-routine maintenance frequently
doubles or even triples the total labor hours expended during a maintenance
check. With the expanded use of composites and titanium combined with
greater discipline in usage of aluminum, Boeing expects the 787 to have much
lower non-routine labor costs than a more conventional metallic airframe.
“There has to
be a very
strong value
case for going
forward with
some
advanced
materials.”
Robert Schafrik,
GE Aviation
3. 2
Jet engines are at the vanguard of commercial aviation's push for new
materials because the heat, stresses and performance demands on them
exceed what nature can offer. General Electric Co. the biggest jet-engine
maker and a world leader in advanced materials, is building new factories to
create composite engine parts. The engines on the Boeing’s Dreamliner are
the first to use a light but strong alloy of titanium and aluminum that engineers
have been developing for more than 20 years.
People often travel by air. But they have no idea that the metals that make up
the Boeing’s engine are working above their own melting point? But if that is
the case why don't they melt?
There are many things that prevent this from happening; first the casting
(forming) process of the part that put little tubes and holes through the piece
which allow air to pass through the part to allow cooling from the inside. This
air comes from the air that is pushing the plane in the air. So a reduction in the
air needed to cool would mean more air pushing the plane. Coatings can be
sprayed onto the parts to improve the melting point of the piece.
Another major trend in the materials used in Boeing’s aircraft is towards nano
coatings to enhance the durability of metals. Nano coatings are now being
used on turbine blades and other mechanical components which have to
withstand high temperatures and friction wear. Tribological coatings can
drastically lower the friction coefficient and improve resistance to wear - this
greatly improves the efficiency of the engines. Materials used for these novel
anti-corrosion nano coatings include silicon and boron oxides, and cobalt-
phosphorous nano crystals. Many nanostructured and nano scale coating
materials have also been suggested as possible friction modifying agents,
such as carbides, nitrides, metals, and various ceramics.
Fortunately, materials development has always been the poster child for
Boeing Co. Today, confidence has increased in composites as a primary
structure, based on 777 successes. Encouraging progress has been made in
aluminum, steel and titanium technologies. Finally, understanding the need for
environmentally responsible processes has also grown. Many technologies
are now maturing in this area and offer an opportunity to design and produce
an airplane that is not only cost and performance preferred, but more
environmentally friendly than airplanes of the past.
The development
of the Boeing 777
was made
possible by the
development of
breakthrough
materials that
allowed
reductions in
structural weight
while maintaining
affordability.
Brian Smith Boeing
Aircraft Co. Seattle,
Washington
