IRL: Indianapolis SAFER barrier press conference, part II

Indianapolis Motor Speedway 'SAFER' Barrier Press conference transcript Wednesday, May 1, 2002 Part 2 of 3 - The technical side Nation: Thank you, Brian. Our next speaker, Dr. Dean Sicking from University of Nebraska. He has with him two ...

Indianapolis Motor Speedway
'SAFER' Barrier Press conference transcript
Wednesday, May 1, 2002

Part 2 of 3 - The technical side

Nation: Thank you, Brian. Our next speaker, Dr. Dean Sicking from University of Nebraska. He has with him two gentlemen who are seated over here, Ron Fowler, principal investigator for Midwest Roadside Safety Facility, and John Rohde, co-principal investigator and associate professor of civil engineering. They'll be available for questions also afterwards. Dr. Dean Sicking, Director of Midwest Roadside Safety Facility, and he is now going to tell you about this particular wall and how it works.

Dr. Dean Sicking: I want to start out by talking about the process. Any time you go to develop a barrier and do a design of this magnitude, it winds up being a very large team. Of course, the leader of the team being Tony any George and his crew, Phil Casey, Brian Barnhart. I really enjoyed working with them. And NASCAR really supported us a great deal with Steve Peterson, Gary Nelson. A couple other people with the University of Nebraska, which is our design team, I would like to give recognition to Ron Faller and John Rohde and Dr. John Reed and Jim Holloway, who have been instrumental in the development of this new design. What I want to do right now with the videotape, and hopefully it has audio dubbed onto it, summarize the development process. I think we have a six-minute video. Can we run the video? I want to summarize the development of the energy absorbing system by IRL. First generation of this system is called the PEDS Barrier, polyethylene energy dissipating system. And the design was developed by IRL engineers and installed on the inside of Turn 4 at the Indianapolis 500. And the first impact was by Arie Luyendyk. This vehicle impacted the barrier about 133 miles an hour, 37 degrees. As you can see, it's a very severe impact. Although the energy absorbing system functioned and dissipated the energy of the impact, it did cause the vehicle to careen across the track at a high angle and distributed much of the barrier out into the track, which created significant problems for bystanders as the debris is knocked into the stands, and also for other drivers on the track. Although the barrier did help save Arie's life, it created some other problems. After that impact, Tony George decided that it was time to find a consultant research group that could offer advice and guidance in the design of an energy absorbing system. And the PEDS-2 Barrier was developed. The PEDS-2 Barrier functions on the same basic principal as the PEDS 1 Barrier, but significantly strengthened to try to increase its energy dissipation characteristic and control the debris field that was generated by the first impact, as you can see by the impact by Hideshi Matsuda during Indianapolis 500. The debris field was eliminated significantly, improved energy dissipation. The barrier worked much better. We then moved back onto our test track to begin to test this system and others to try to develop a design that could effectively dissipate the energies from high-speed impact. One of the things we looked at was high-density polyethylene skin system, as you see here. It uses high-density polyethylene sheets as the energy dissipation mechanism, and then a high-density skin on the surface. Notice the significant pocketing around these sheet energy absorbers. The pocketing causing significant longitudinal and lateral decelerations. It literally slows the front of the car down, pulls it into the barrier, thereby increasing the risk to injury of the driver. Notice how this vehicle instead of being straightened, the front of the vehicle is actually stopped it causes the vehicle to spin out, increasing the risk of injury to the occupants. This was a behavior our analysis showed that occurred any time we had a high-density polyethylene skin associated with discrete energy absorber, either polyethylene tube or polyethylene sheet. Any of those discrete energy absorbers would allow this significant pocket. Based on that result, included that if we wanted to use the high-density polyethylene skin, we had to move to a distributed foam energy absorbing system that would eliminate that high degree of pocketing. We then began to test with passenger cars. This is a conventional passenger car impacting at 100 miles per pour, 20 degrees. As you can see, the barrier doesn't deform very much. It doesn't provide a great deal of energy dissipation. But we still see some degree of pocketing around the vehicle as it impacts that polyethylene skin. Notice the pocketing right at the front of the load. There's significant angle of the polyethylene sheet relative to the front of the car, and that's slowing the impact side of the car down and pulling the car into the barrier. We then tested the same system with an open-wheel race car. And, again, we didn't see a great deal of energy dissipation in this impact, but the pocketing was somewhat less with this vehicle than it was with the passenger car. And notice the very flat trajectory. So there were some advantages of this system. It did help limit some of the lateral acceleration and the vehicle trajectory was very good. But we were very concerned about pocketing we observed in both of the first two tests. We then went to a steel skin system. The principal here is to provide a tubular steel wall with tremendous bending strength. The bending strength of the wall element will prevent it from wrapping around the front of the car and virtually eliminate the pocketing. As you see here, there's no pocketing of this vehicle inside this barrier. We also coated the surface of this barrier with zinc rich paint. The zinc provides a lubricant, which further reduces the friction between the vehicle from the barrier. By reducing the friction, we reduced the longitudinal deceleration, which, again, as I mentioned previously, longitudinal deceleration pulls the car into the barrier, increasing the acceleration of the driver. The performance of this barrier was greatly improved, and we saw a dramatic reduction for this crash in the lateral accelerations and longitudinal accelerations when compared to a similar crash with a concrete barrier. As you can see, this barrier incorporates foam energy absorber, spaced foam energy absorbers basically tuned for the lightweight open-wheel cars in IRL racing. We then needed to adjust this barrier, the same barrier system, so that it would work with the heavier Winston Cup stock car vehicles, so almost twice as much. So our first attempt involved using virtually a solid foam system and the same steel skin. And as you can see here, although there was some modest deprivation of the wall, there was very little energy management in this system. It was -- it had significantly more energy absorbing foam than was necessary for this vehicle. But, again, there was no pocketing and the vehicle longitudinal accelerations were very low, and the lateral accelerations were reduced somewhat. Continuing on in this research, we then used computer modeling and component testing to refine the barrier design and reduce the amount of energy absorbers used in the wall. What you see here is another test of this barrier. Notice how much more lateral movement we get in the wall and significantly improved energy management in this system. Also, notice that there is virtually no pocketing in this barrier system in this crash test. Again, the vehicle exit angle is dramatically reduced compared to the Luyendyk crash to the barrier, which has created significantly improved performance. We then continued with our development in testing and tested the barrier with a higher-speed impact using an open-wheel car. What we're highlighting here is the joint design. Notice this is up, the joint, attempting to provide maximum loaded on the joint with the concern that it may open up and allow some snagging of vehicle components in the joint. The joint is designed to close up during an impact as the barrier moves back. The gap between the adjacent segments is eliminated as the barrier moves backward, thereby precluding the opportunity for any snagging at the joint. Another concern we had with the barrier was potential for significantly delaying the race if it was damaged during a severe impact, such as the one shown here. We tested this design several different times under extremely high-energy impacts and found that the functionality of the barrier was maintained, and there would be never any reason to stop or delay the race to repair the barrier. We believe the barrier that was developed under Tony George and Indy Racing League leadership in cooperation with NASCAR will provide significant improvement in safety for both open-wheel and stock car racing venues. We look forward to this barrier being implemented on a number of tracks so that we can get some real-world crash experience.

Nation: Thank you, Dean Sicking. Our final speaker is Kevin Forbes. Kevin is the director of engineering and construction for the Indianapolis Motor Speedway. He has supervised the installation of this new energy-absorbent wall system, the SAFER system.

Kevin Forbes: Thank you, Fred. Good afternoon. Well, I think that the real test of any brand-new device that has been developed and tested is its applicability to real-life situations. As we have been proceeding with the fabrication, construction and installation of Dr. Sicking's invention, we found it to be exactly that. Very, very applicable in all ways in its installation. Obviously, one of the big concerns in any racetrack is how long it might have to be down during the installation of this device, and it was designed to be installed quickly, and we found out that exactly, that it can be installed very quickly. There's preparation work that had to be done ahead of time, but that all can be scheduled very nicely with other racetrack activities. So what we found is that our racetrack actually had zero downtime for the installation of this barrier. I think that's very important for other racetracks that may want to consider something like this or this device in the future. The other thing that we found out, and I think that is very important for this application, is that if in fact there is a catastrophic damage done to one of the sections, it was also designed to actually replace individual modules or sections of this wall. And, again, we found out that that's very much the case. That's very important during racing time, where if we do have a section of this damaged and it's felt appropriate to change out the section, it can be done so virtually in the same amount of time that the incident itself has been cleaned up. Third thing that we have discovered with this is that it is very applicable to other racetracks. That the selection of materials are such that they are readily available in any other part of the country. Although I think we had probably, in my mind, one of the premier structural steel fabricators and erectors to help us in to fabricate and install this. I think that any company of their caliber across the United States can do the very same thing at any other racetrack. I think that it would be very easy to kind of take these details that we have used here and to refine them so that they would fit other racetrack geometries, racetrack bankings. One of the things that we have found out is that we had to make some very minor adjustments to ensure that we did not negate any sight lines. I think that's something we have been learning here over the year, we are becoming very sensitive to spectator sight lines. This is very adaptable to any racetrack with sight lines. I think -- in summary, I think this, as far as the installation of this barrier, as far as the expected outcome, I think it's everything that we felt and hoped it would be.

The questions

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About this article
Series Automotive , IndyCar , NASCAR Cup
Drivers Arie Luyendyk , Tony George , Brian Barnhart , Matsuda Hideshi