Autoliv safety tests
Michigan company at forefront of Earnhardt probe
By Mike Fish, CNNSI.com
AUBURN HILLS, Mich. -- Believe it, seat belts tear and break.
Still, that fact is one of the great mysteries in the crash that killed Dale Earnhardt. The idea of his three-inch wide, heavy-duty lap belt ending up in two pieces is mind-boggling, even if it didn't cost him his life. A nylon belt just doesn't split, right?
It can happen, and to believe maybe you have to witness for yourself.
Autoliv, contracted by NASCAR to investigate Earnhardt's failed left lap belt, recently staged a demonstration at its technical center in a Detroit suburb for CNNSI.com, showing that in isolated, rare circumstances the improbable can take place before your eyes. In this case, the nylon fabric doesn't lay flat, but is instead purposely "bunched up" in the metal adjuster.
To further make its point, Autoliv representatives played a video of a crash test they conducted, where a lap belt failed on a car's impact with the wall. The metal adjuster, resting at an angle and not being perfectly perpendicular to the belt, triggered the failure, ripping the belt in two.
"This isn't the first time it has happened," said Chipp Jackson, Autoliv's marketing manager. "We've duplicated it in static scenarios. It is a possibility. NASCAR has gone through the garage and inspected cars and belt mounting and adjusters, and they have been very proactive to look at it."
What causes a failure?
"Installation could be a factor," said Jackson, who has worked closely with several NASCAR race teams on safety programs. "How it is mounted? Where it is mounted? It is not local to any particular belt manufacturer. Or a stock car versus a passenger car."
The belt manufacturer reference seems to clear Simpson Performance Products of any suggestion that belts provided Earnhardt were of shoddy quality, particularly if it's more an issue of how they were later used.
In the live demonstration, safety engineers subjected an untagged black racing belt to a pendulum test, one of a series of tests Autoliv could be expected to run on belts identical to those worn by Earnhardt.
The test applied 2,484 pounds of pressure to the belts, about equivalent of the load expected in a 35 mile-an-hour crash -- which is the change in velocity you'd see in a car that goes into a wall at 185 miles-an-hour and comes off at 150, similar to Earnhardt.
The result is a torn belt. Not ripped on a straight line, but at a jagged, uneven angle.
"It is edge loading," explained David Funnell, an Autoliv seat belt engineering manager who's worked the Earnhardt investigation. "When you start to load any fabric on the edge, it will start to tear faster than if you just load it down straight. Take a piece of paper. If I pull on it evenly, it is less likely to tear. The same thing happens with any fabric."
The pendulum test is often helpful in measuring the effect, as it mirrors the actual spike that an occupant would experience in a crash.
"One of the things it shows you is a sharp spike," Jackson said. "If you know the vehicle velocity or the speeds or the G's [g-force] that the occupant encountered, you try and go back and simulate that same scenario on a pendulum. It is a hard spike just like a crash is. It is hard, right now. And then you turn around and try to repeat that, and see if there is any repeatability [of a belt breaking]."
Funnell joked that he was "sworn to secrecy" on matters related to Earnhardt, but the fact is Autoliv and the other independent experts participating in the investigation have signed confidentiality agreements with NASCAR. So officials of the Stockholm-headquartered firm spoke only in general terms of how they might investigate the failure of a seat belt.
A 30-degree right front hit into the wall, for instance, sends the driver to his right every time.
A hit into the wall like that is feared because of the resulting bullwhip effect, with the head going to a certain point and then snapping the other way.
And a 185 mile-an-hour hit into the wall isn't really what interests safety experts, but the measured change in velocity.
"You can watch the films of Feb. 18 -- when you go sideways long enough those tires are still gripping the pavement, sucking energy right out," Jackson said. "So, did Dale hit the wall at 185 miles-an-hour? No. Nobody ever really does because of the absorption and the friction."
Autoliv had already been involved with Stacy Compton's No. 92 car as well as testing for NASCAR before the Earnhardt crash in February, but it had made its reputation outside the sport as one of the largest safety-restraint manufacturers, employing 30,000 people in 36 countries. Last year alone, it supplied 50 million sets of seat belts and 40 million air bags.
With NASCAR expected to release its findings later this month, Autoliv is, however, the only company so far to be identified as having a role in what is now an almost six-month investigation.
NASCAR officials are putting a seven-figure price tag on the probe. But Autoliv has just a small, albeit juicy part of the pie -- to run tests aimed at figuring out why the belt broke. Some suggest that might be the only real news in what is nevertheless anticipated to be a beefy report.
It's widely accepted that belt failure was not a factor in Earnhardt's death, thought instead to be the result of a basal skull fracture caused by the whiplash-like motion of his head as his car struck the concrete retaining wall at Daytona International Speedway.
To date, the most authoritative statement has come from Dr. Barry Myers, a court-appointed expert from Duke University, who after viewing autopsy photos said Earnhardt suffered a skull fracture when his head whipped forward.
"All of us that have seen the autopsy [report] and those of us involved with these kind of things, we don't expect anything startling from a medical aspect to come out of it," said Dr. Steve Olvey, CART's medical director and neurosurgeon at the University of Miami's Medical Center. "The big issue everybody is curious about is the seat belt. Most of us are hoping the report sheds some light on exactly what happened with the seat belt."
Clearly, the acceptance of belt failure is a general theme within the racing community.
"Even though NASCAR has already announced it, and we see where Earnhardt Jr. said that the belt broke -- why did the belt break?" said H.A. "Humpy" Wheeler, president of Lowe's Motor Speedway in Charlotte, N.C. "Well, I think it is also pretty well understood by the people within the business that it was not Simpson's fault. Something happened to that belt."
Bill Simpson, founder and former chairman of Simpson Performance Products, said he was unaware of Autoliv's specific role in the investigation. Simpson announced his resignation from the safety products company July 31.
But asked what he hoped was being done with the safety belts, Simpson said: "They would have to do a scientific analysis, probably do some crash tests and sled tests. They'd have to have the seat belt installed exactly the way it was installed in the car we're talking about. They'd have to subject the belts to microscopic examination."
That sounds like what the Autoliv folks have been up to.
Inside a sprawling complex here, which houses almost 500 employees, Autoliv experts have the equipment to run about every known scientific test on belts. The range includes a static test that pulls the belt to the point of destruction, a pendulum test where there's a very sharp impact to the belt, and a sled test that simulates the actual crash with the belt geometry over a crash dummy.
NASCAR requires the date of manufacture to be visible on belts, so it's logical to assume Autoliv got its hands on other Simpson belts produced about the same time as those worn by Earnhardt. If so, they've likely been run through tests -- all of which would attempt to duplicate or mirror the speed and angle of Earnhardt's car into the wall, its deceleration rate, his size, as well as the way his belts were anchored inside the car and worn by the veteran driver. "If you have all the conditions right, there is a chance it will break again when exposed to the same conditions," Funnell said.
Understandably, Autoliv isn't uttering a peep about what it found until NASCAR goes public with its report.