Material Selection For Automotive Spaceframes

Material Selection for 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.
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Crossmember Component