By Nancy Garcia
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BREAKTHROUGH -- Three members of the team that won an R and D 100 award for technological innovation at Sandia this year (from left), Doug Bammann, Mark Horstemeyer, and Mike Chiesa, display a control arm from a Cadillac steering system, a part designed with their winning mechanical-property code. This potentially revolutionary code allowed the part to be designed with a nearly 30 percent weight savings and accurately predicted where the part would break during mechanical testing. (Photo illustration by Lynda Hadley)
"This year's R&D 100 awards recognize the Department of Energy's continued contribution to our nation's economic prosperity and well-being," says Secretary of Energy Bill Richardson. "Energy Department laboratories are a wellspring of innovation, and I congratulate the researchers on their success."
The material-modeling software takes into account a wide range of metals: tantalum, steel, aluminum, copper, and more, Doug says. It can be run on any computer platform.
Cadillac has already used it
"A guy on the shop floor could run the program and see how to adjust for distortion," he says. "It allows you to track, physically, what's happening with the material and predict the material response." Already, it's been used to decrease by nearly 30 percent the material needed to create a Cadillac control arm (part of the car's steering system). Optimizing automotive parts allows cars to be lighter, and thus more fuel-efficient, which helps lower emissions. This optimization also decreases material costs and permits better quality parts.
Team member Mark Horstemeyer (8726) says he was able to predict where, during testing, the control arm would ultimately break in mechanical tests. When his prediction was eventually borne out, he says, he received a standing ovation from representatives of 40 companies involved in the cooperative research. The work is known as the "USCAR-USAMP-AMD Project: Design and Optimization for Cast Light Metals." This five-year cooperative research and development agreement (CRADA), which ended last year, involved the US Council for Automotive Research's US Automotive Materials Partnership.
"Various casting programs have been trying to accomplish prediction models for years, but it finally took a very accurate material model that captures true physics of deformation and damage to show where failure would occur," says Don Penrod, the American Foundrymen's Society executive administrator for the project.
In a letter supporting the award nomination, General Motors Corp. staff development engineer Richard Osborne heralded this "unique, yet practical, capability that could revolutionize the process for designing automotive components." Said Osborne, "Other material models do not have the accuracy of this model because they do not include microstructure and discontinuity information."
Those qualities, Mark says, influence how a part will fail mechanically. These pertinent cause-and-effect relationships were included in the model, which requires a small set of data and can be run relatively rapidly for very complicated situations.
Working with colleague Vince Prantil (who has since left Sandia for Milwaukee School of Engineering), Mark made significant modifications to a modeling program Doug and Mike Chiesa (8727) had created earlier to aid in forging designs of gas transfer systems. (Mike is a member of the winning team.) This adaptation realistically takes into account the effects of a variety of conditions (such as strain rate, temperature, and microstructure) on material response.
Crashworthiness analysis too
Related work was carried out under a six-year CRADA with the National Center for Manufacturing Sciences, the largest cross-industry consortium in the US, with more than 200 member companies. In this work, the microstructure-property model was applied to simulate heat treatment and quenching applications for a variety of steels, and incorporated in a software package, scheduled to be released soon, named DANTETM. Besides improving automotive parts, the team believes this modeling approach can also be applied to crashworthiness analysis for all types of vehicles, including trains and aircraft. Mark is working with geophysicist John Baumgardner of Los Alamos National Laboratory to use the model to understand how upper mantle convection applies to earthquakes and volcanoes, and Doug is extending the model to small parts used in microelectromechanical systems. The suite of uses ranges over a wide range of applications.
Other contributors include Sandians Esteban Marin (8726), Richard Reguerio (8726), and Paul Taylor (9232). Outside collaborators sharing in the award are consultants Mel Callabresi and Jim Lathrop (former Sandians); professor George C. Johnson of the University of California at Berkeley; professor Mark Lusk of the Colorado School of Mines; and professor David McDowell of the Georgia Institute of Technology.
Last modified: September 12, 2000
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