EDITORS: The complete report is available to reporters at no charge from the Office for the Study of Automotive Transportation, (734) 764-5592.

ANN ARBOR—Despite the trend of using more lightweight, but expensive, aluminum, plastics and structural composites, reducing costs will continue to be the main challenge for North American automakers in choosing vehicle materials in the next decade, according to University of Michigan study.

“It is very clear that the cost of materials and processing is the most important material-selection decision criterion,” says Brett C. Smith, who conducted the study for the U-M Office for the Study of Automotive Transportation. “Given several years of severe price competition, it is not surprising that cost reduction has been placed at the forefront of vehicle manufacturer purchasing strategy.”

In their report on automotive materials—based on responses of more than 200 auto industry experts in the 10th biennial U-M Delphi Forecast and Analysis of the North American Automotive Industry—Smith, an analyst with the Center for Automotive Research, and retired General Motors executive Michael DiBernardo found that weight, formability, design and styling requirements, safety considerations, warranty costs and field experience also will be important factors in material selection in the coming decade.

According to the study, total vehicle weight is forecast to decrease 10 percent for both passenger cars and light trucks by 2009, thanks in part to expected increases in Corporate Average Fuel Economy (CAFE) requirements. The weight reduction will be achieved through greater use of aluminum and plastics and less use of low-carbon steel and cast iron.

However, this material substitution will come at a high price, especially for aluminum, the researchers say.

“Raw material cost is the most critical barrier to increased aluminum application,” DiBernardo says. “Interestingly, the metal’s price volatility may be almost as disconcerting to automotive engineers as its relatively high price. In many instances, a vehicle manufacturer can justify the higher cost of aluminum given its many positive attributes, yet the fear of unstable prices may still make it difficult for an engineer making the material selection to specify aluminum.”

In addition, formability issues, the challenge of joining and bonding aluminum, and its compatibility with current assembly facilities are other barriers that will prevent greater use of the metal.

The Delphi survey respondents indicate that steel will continue to be the dominant material in frame construction, body panels and chassis components in the next decade, although aluminum is expected to be used more often as frame material (15 percent) and space frame material (20 percent) by 2009.

In fact, aluminum is forecast to see increased application for car hoods (22.5 percent) and decklids (17.5 percent), and for truck hoods (30 percent) and rear hatches (17.5 percent). Further, plastics are expected to see greater use in car fenders (15 percent) and doors (10 percent), and in truckbed applications (20 percent).

While the auto industry still relies heavily on steel for body and chassis applications, it will continue to substitute lightweight materials for cast iron and steel in many engine applications, such as cylinder heads and engine blocks, according to Smith and DiBernardo.

Finally, the recyclability of automotive materials and related environmental concerns will continue to pose significant challenges to the entire industry, the researchers say. While currently about 75 percent (by weigh) of each vehicle is recycled through the removal of resaleable parts, fluids and metals, the remaining 25 percent—comprised mostly of plastics—ends up in landfills.

“At a time in which the automotive industry has become increasingly aware of the environmental impact associated with the final disposition of their product, plastics use in automobiles has greatly increased,” Smith says. “Industry must proactively work to reduce the percent of the vehicle that goes to landfills, and a key element of that strategy is the increased recyclability of plastics.”

For more information about the Delphi automotive materials report, contact OSAT at (734) 764-5592. OSAT, a division of the U-M Transportation Research Institute, provides research and analysis on a wide range of automotive issues, primarily focusing on strategic issues, competitive developments, and challenges forcing major changes in the industry’s structure and functioning.