Soft-Wall Barrier to Make Racetracks Safer
After more than three years research and painstaking documentation of 20 crashes, researchers at the Midwest Roadside Safety Facility at the University of Nebraska-Lincoln are at Indianapolis Speedway this week to see the first installation of an energy-absorbing wall.
The barrier technology, to be constructed on the speedway turns for the Indianapolis 500, is a breakthrough for the motorsports world and a huge feat for the engineers at Nebraska.
The technology is a wall safety enhancement that could make this dangerous sport safer, the UNL researchers said.
"We're trying to make impacts less strenuous on the drivers in the racecars and reduce the potential for serious injuries," said Ron Faller, research assistant professor at the Midwest Roadside Safety Facility. Faller, facility director Dean Sicking and associate professor of civil engineering John Rohde are in Indianapolis this week to unveil the barrier in a much-anticipated announcement just weeks before the Indianapolis 500 race.
The barrier system works as an energy absorber, dissipating the impact energy and distributing it over a longer distance of the wall without propelling it back into the high-speed traffic. Configured with an outer steel skin formed with structural steel tubes and welded together on top of one another to form an impact plate, underneath is as much as 14 inches of energy absorbing plastic foam, in polystyrene blocks, spaced behind the steel skin to absorb the impact.
"The overall wall system is designed to attenuate some of the kinetic energy coming in from the impacting vehicle and mitigate the severity of the crash had it contacted a concrete wall," Faller said. "The impact should be less severe when it contacts our energy absorbing wall."
The project began in January 1999 when Indy Racing League officials asked the roadside safety group to assess the high-density polyethylene barrier in use then at Indianapolis. From there, UNL engineers created an alternative design using the steel-on-foam technology and IRL officials asked them to continue with the prototype and research the design. In the midst of the design and testing phase, NASCAR driver Dale Earnhardt was killed in a wall-impact crash, increasing public interest in the technology. NASCAR officials had joined in the development and research earlier.
Faller said 20 vehicles have been crash-tested at the MwRSF test site at the Lincoln Municipal Airport, including 12 race cars, including Winston Cup cars, and open-wheeled Indy-style race cars. At speeds of as much as 150 mph and at varying impact velocities and impact angles, using regular concrete barriers as control measures and the new energy-absorbing barrier, the data from the tests has been analyzed and documented and provided to IRL and NASCAR officials.
Jim Holloway, a research associate engineer of civil engineering and the crash site director, oversaw all 20 crashes and the data collection and management on each.
"We're studying the forces out there, the dummy data and then all the photography during the wall impact," said Holloway. "Whenever you're developing a product to make it safer, you have to have data. And of course in real races they don't equip these vehicles with high-speed cameras nor the number of accelerometers used in our crash testing program.
"That's exactly what these tests are for, to prove the benefits of our system."
Holloway and the safety facility's team of more than 30 engineers and staff used as many as 18 high-speed cameras operating as high as 500 frames per second to capture every split-second of the crash impacts.
"These impact conditions are very critical because in order to do a comparison you must have similar impact conditions, with the angle, the speed and the weight of the vehicle, to compare," Holloway said.
Actual cars costing as much as $200,000 were used in the final phases of the research.
"This from the Penske team, it's the number 2 car with driver Rusty Wallace," Holloway explained at a test in April. "It's a real car, and was racing this year. We need to know structurally the strength of the car, is it one that they're using now, has it had safety improvements' that all becomes a factor in this testing."
The energy-absorbing barrier design can be modified between races to accommodate different race car styles, open-wheeled and stock, which is important because some racetracks run different styles of cars on the track on different weekends. The design allows track operators to add or subtract layers of foam depending on the car style.
The research is important not only because of the high-visibility nature of racing sports, but because the knowledge gained benefits the roadside safety researchers.
"Right now we only have the design developed for racetrack applications, but we are considering what avenues exist for taking this technology into the roadside community and applying it along our highways," Faller said. "We haven't done any development work for highway applications at this time. It could be fairly expensive and it might have limited applications."
"That's what our mission here. To save lives on the roadside."
Contact: Kelly Bartling, University Communications, 402-472-2059Digital video, digital photos available.
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