Automotive Spaceframes
Aluminum usage in automobiles and light trucks
has been climbing steadily. Even
more important, auto manufacturers are
beginning to see aluminum the way
aircraft manufacturers do - as the basic
structural material for their vehicles.
Increasingly, in the case of
carmakers, that thinking begins with an aluminum
body structure such as the
spaceframe. It's a new and potentially powerful
trend. As recently as 1990,
there were no aluminum-structured passenger cars in
production anywhere in
the world. The closest thing was the HMMV (Hummer), at
that time strictly a
military vehicle. As of 1997, there were seven
aluminum-structured passenger
cars in production. For three of them - Audi A8,
Plymouth Prowler, and GM
EV-1 - Alcoa has been the principal partner in
designing, engineering and
manufacturing aluminum components, subassemblies, and
- in the case of the
Prowler - the frame itself. And that's just the beginning.
A concept car
with a modular spaceframe in technology reviews held for Ford
and
Chrysler, Alcoa unveiled a vehicle concept embodying ideas for future
cars and
light trucks. The design is based on a spaceframe structure
comparable to those
Alcoa has helped to develop for the Audi A8 and
Plymouth Prowler. But in the
concept vehicle, the spaceframe is modular, a
step toward using such structures
in a broad range of future vehicles. By
changing modules, a carmaker could
produce a sedan, a sport utility vehicle,
and a pickup truck, all from a single
production platform. New programs with
Daimler-Benz and Chrysler Alcoa is
producing the front energy management
structure for the new Mercedes-Benz
A-class car (above) now selling in
Europe. This 11-piece structure was designed
by Alcoa and is robotically
assembled at Alcoa's plant in Soest, Germany.
Production volume is
expected to reach 1,000 units per day. For Chrysler, an
aluminum rear
crossmember designed and manufactured by Alcoa improves the
handling and
noise-vibration-harshness performance of the all-new 1998 Dodge
Intrepid
and Chrysler Concorde as well as the 1999 Chrysler LHS and 300M
models.
AAS will manufacture 270,000 units per year at its Northwood,
Ohio plant.
Something new around the windshield. A key advance
incorporated in the 1997
Corvette is a first-of-its-kind windshield
surround developed in a design and
engineering collaboration of General
Motors and Alcoa. An effective combination
of aluminum cast and extruded
products makes this an extremely stiff structure,
helping the new Corvette to
earn excellent reviews for its stiffness and
superior handling. Northwood
will produce 25,000 windshield surrounds annually.
.Design tools to aid in
product development New guidelines for use in designing
automotive components
have been installed at AAS operations in Esslingen,
Germany; Southfield,
Mich; and Alcoa Technical Center (ATC) near Pittsburgh.
Developed by AAS
and ATC, the guidelines will assist automotive engineers in
evaluating
product design and fabrication options. Objectives: Improve design
quality
and cut development time by 30%. Audi A8 is picked as a technological
winner
In December, the Audi A8 was named one of the top 25 Winning Technologies
by
Industry Week (IW) magazine in the U.S. The editors report: "The
1997
Audi A8 with its aluminum spaceframe body technology indicates what
is possible
when the status quo in materials is challenged in automotive
design. The luxury
sedan delivers a new standard in weight savings,
structural integrity, safety,
performance and comfort." IW traces the origins
of the Audi spaceframe to
"an early 1980s R&D initiative that became a
joint-venture with Alcoa.
The spaceframe took 10 years to develop," the
editors note, "and is
the result of 40 new patents, seven new aircraft-grade
aluminum alloys, and
extensive design analysis via supercomputers." Alloy A
substance with
metallic properties, composed of two or more chemical elements
of which at least
one is a metal. More specifically, aluminum plus one or
more other elements,
produced to have certain specific, desirable
characteristics. Alumina Aluminum
oxide produced from bauxite by an intricate
chemical process. It is a white
powdery material that looks like granulated
sugar. Alumina is an intermediate
step in the production of aluminum from
bauxite and is also a valuable chemical
on its own. Aluminum Spaceframe An
integrated structure of aluminum castings and
extruded parts that forms the
primary body frame of a new generation of
automobiles. Bauxite An ore from
which alumina is extracted and from which
aluminum is eventually smelted.
Bauxite usually contains at least 45% alumina.
About four pounds of
bauxite are required to produce one pound of aluminum.
Brazing Joining
metals by flowing a thin layer of molten, nonferrous filler
metal into the
space between them. . Crossmember Component of a vehicle
structure that spans
the structure, joining two sides together. Engineered
product A basic
aluminum fabricated product that has been mechanically altered
to create
special properties for specific purposes; forgings and extrusions
are
examples of engineered products. Extrusion The process of shaping
material by
forcing it to flow through a shaped opening in a die. Fabricate
To work a
material into a finished state by machining, forming or joining. It
all starts
with dirt. This kind of dirt is called bauxite ore. If you looked
at a four-ton
truckload of it and someone asked, "What can you make out of
that?" -
you would think, "Not much. Maybe the base for a driveway." But
from
four tons of bauxite, it's possible to refine about two tons of alumina
- a
powdery oxide of aluminum. It's not easy. The technology is complex and
the
equipment is massive. But Alcoa has refined the refining process to an
art..
And from those two tons of alumina, we can smelt a ton of aluminum.
Smelting
aluminum. Smelting aluminum was the invention that launched Alcoa
launched Alcoa
111 years ago. A ton of aluminum is enough to make the
cans for over 60,000
Cokes, Pepsi's or Buds. Enough to make the
spaceframes for seven Audi A8 luxury
cars. Enough to make40,000 computer
memory disks, capable of storing all the
books ever published. . Aluminum is
the most abundant metallic element in the
earth's crust and one of the more
difficult to extract. It is always found
locked in combination with other
elements such as oxygen or sulfur, as part of
various aluminum-bearing
minerals notably bauxite. Once converted into its
metallic state, aluminum is
like no other material on earth. Its future is
bright because its combination
of useful properties is extraordinary. Aluminum
is eminently recyclable.
Aluminum pays its own way through the recycling loop.
Making aluminum
from recycled scrap takes only 5% of the energy it would take to
make new
metal from ore. Aluminum is... Light in weight - about a third as heavy
as
copper or steel. Highly resistant to corrosion. Strong, and can be made
still
stronger by adding small amounts of other metals in alloys. An
excellent
conductor of heat and electricity. An excellent reflector of heat
and light.
Nonmagnetic, a valuable property around compasses or sensitive
electronics.
Nontoxic, thus often chosen to package foods, beverages, and
medicines.
Outstanding in cryogenic properties - strong, not brittle in
intense cold.
Highly workable, capable of forming by all known
metalworking processes.