Third generation steels will marry high-strength steels with greater formability to produce optimized lightweight structures for future vehicles.
"If the steel industry hadn't done the ULSAB projects, we would not have had good, clear examples of how it could improve itself in light of all the pressures to reduce weight out there," says Ron Krupitzer, v.p., Automotive Applications Market Development, American Iron and Steel Institute (AISI). The original ULSAB-Ultra Light Steel Auto Body-program was a material replacement project, while its Advanced Vehicle Concept follow-up was the steel industry's reply to the fact that it wasn't invited to the government/industry Partnership for a New Generation Vehicle program. "Ironically," says Charles Potter, senior consultant, Automotive Applications Market Development, AISI, "A lot of the things that came out of that program-taking a holistic approach to the structure, new high-strength steels, etc.-are evident in the new vehicles on the road today." But what about tomorrow and its requirement for a 35-mpg fleet average?
That's where the next project, "Future Steel Vehicle 2020," comes in. It is an answer to those who contend that steel is-once again-out of the picture. "One thing that our work with Porsche Engineering on the ULSAB-AVC program taught us was that you have to bring the materials and architecture together so that they can be optimized together," says Potter. On the materials side, the work includes creating more formable versions of high-strength and ultra-high-strength steels in concert with the National Science Foundation (NSF). "We done studies based on our recent work with the Dept. of Energy," says Krupitzer, "and-even though we saved a lot of weight by working on things like the future-generation passenger compartment-our computer analyses show that we could save a lot more weight if we could make additional parts of these higher-strength steels." The NSF is working with three universities to create third-generation steel that is very formable, but at a reasonable cost. It will be combined with topology optimization that places the right steel in the right place throughout the structure, as well as parametric analysis that looks at all of the possible combinations of mass-savings ideas throughout the vehicle in order to pick the ones that can save the most at the least cost.
"The one major difference," says Krupitzer, "is that the vehicles themselves are changing. The increase in hybrids, dual-power drive systems, and fuel cells will affect not only mass distribution, but how you package the drivetrain and its accessories." Creating a strong, lightweight, affordable structure for these components may alter the overall vehicle structure significantly. "Steel has the opportunity to change and be reinvented such that it meets these needs while keeping costs down," he says. It is an approach that will start with EDAG Engineering + Design (Fulda, Germany; www.edag.com), an engineering firm retained by the 16 steel companies involved in the project. They are interviewing researchers at each major car maker in order to get an idea of what powertrains will be in use in the post-2020 timeframe, their expected size and weight, and how they will be packaged. "Where you place the batteries and fuel storage medium, as well as the power distribution system," says Potter, "will determine where the mass is within the vehicle. That may require a new steel structure to optimize the mass per axle."
The first phase will be completed this year, and provide inputs for creation of the design concepts and the eventual build of demonstration hardware. As Potter sums up: "In these times and in this market, if you don't stay right up front and push the boundaries, you get left behind." The steel industry isn't about to let that happen again.