AREA NEWS
Story last updated at 1:00 p.m. on Friday, November 27, 1998

photo: news

  Thomas Zacharia, left, and Srdan Simunovic examine the Audi A8 frame recently sent them by the company. The aluminum frame will be crash-tested to help the Oak Ridge National Laboratory researchers create a computer model for the car.
Photo by Barbara Younkin

Computer model will save cash for auto research

by Larisa Brass
Oak Ridger staff

   As Thomas Zacharia and his colleagues drive their shiny black Audi A8 from building to building at Oak Ridge National Laboratory, they're counting down the days until the top-of-the-line vehicle is reduced to a crumpled pile of metal -- thousand dollar tires, Bose speakers, six-changer CD player and all.
   "When you are crashing a $70,000 car, you don't worry about it," says Zacharia, director of the Computer Science and Mathematics Division.
   And for those of us who cringe at the thought of recklessly smashing into the side of a wall a car we can never hope to own, this crash-test candidate will save others like it from such a demise.
   Zacharia and other researchers at the lab are creating a computer model of the sedan -- a model that will allow them and their partners to simulate all varieties of crashes and test for other things as well.
   "So what we want to do is develop these models, gather data and test it and have a model we are confident in so that we can play what-if games," he says.
   The Audi is one of a series of vehicles ORNL is modeling for the Department of Transportation, the Department of Energy and the Big Three automakers in Detroit, Mich.
   The Audi was chosen because of work the lab is doing on cars of the future -- vehicles that will weigh less and be more efficient.
   "Primarily why we chose (Audi) is the next generation vehicles . . . are going to be aluminum-intensive vehicles," Zacharia says. "So this is our attempt to try to see how an all-aluminum vehicle will behave."
   Right now, that data collection is in various stages and sites throughout the lab. Zacharia takes us on a tour of what he and others have dubbed an "Audi body experience."
   Stop #1 -- The skeleton
   Sitting under a shelter on a gravel lot, it's just been delivered by FedEx. Pieces of crate are still stacked around it.
   It's the all-aluminum frame of the Audi, and Zacharia and Srdan Simunovic, a lab researcher and computer programmer for the Audi model, examine it for the first time.
   The frame will be taken to a crash-test facility, where it will be placed on a moving slide and propelled into a barrier.
   ". . . The reason for this is that we test this vehicle without the engine, just to get a sense of . . . without the engine and without the transmission, how the body itself behaves in a crash test," says Zacharia.
   Stop #2 -- the body shop
   Zacharia and Simunovic next drop by the mechanic's shop, where lab vehicles are repaired . . . and where a dismembered green Audi sits in the corner.
   Covered with a grid of tape, this is where the car is scanned and the computerized model is created.
   The scanning process not only creates the shape of the car, but also takes into account the weight of the part, the material it's made of and how it relates to the parts around it.
   "It's a scanning device that looks like an arm and when you touch a point with that arm, then the coordinates of that point are fed into the computer," Simunovic explains.
   That's his job, creating a computer model of the Audi that will behave just like the real thing.
   When they began doing modeling, back in 1993, says Zacharia, the results were fairly rough and approximate, because it took about six weeks to create a model with only 28,000 elements.
   With today's parallel supercomputers, it only takes hours to run through a scenario that includes millions of elements.
   "So now we can get the results in very high fidelity and look at things in much detail," he says.
   The computer image will even show the emblem on the hood.
   Enough information is put into the computer to create about as many "what-if" scenarios as Zacharia and Simunovic can imagine.
   After the data has been entered and a model established, the Audi A8 itself will be crash-tested to confirm the computer info and adjustments will be made.
   Once the model is fine-tuned, lab researchers and their partners can try out any type of collision on the car. They can also try out new ideas.
   "Once we have a validated model, it allows us to play what-if games," says Zacharia. "What if we replaced this aluminum sheet with an aluminum foam material? What if we changed this design this way or that way? Is it beneficial?"
   


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