Milwaukee VA Medical Center
Crash tests yield valuable safety data
They take hours to set up and are over in a split second. But the information they yield is immeasurable.
Staff in the Medical College of Wisconsin’s Vehicle Crashworthiness Lab on the Milwaukee VA Medical Center grounds have been conducting crash tests recently, working to learn more about the effects of vehicular collisions on people – specifically as it relates to passengers who may be in reclined seats.
The thinking is that with the coming of automated -- or self-driving -- cars, more riders will be in a reclined position, and that could affect what happens during a crash and how safety precautions – particularly seat belts – can be improved to provide better protection.
“As we get more automated vehicles, we’re going to have different postures, and one of the things we’re worried about is the relaxed posture of reclining your seat,” said Dr. Frank Pintar, director of the crash lab and a professor of neurosurgery with the Medical College of Wisconsin. “Are we looking at different types of injuries?”
The results of the testing will be sent to the National Highway Traffic Safety Administration
“They don’t have very much crash test data on (automated cars),” said research technologist Austin Amato. “By doing this, we can get an idea of how people will react and how their bodies will move in those situations … which helps in the creation of safety guidelines for newer cars.”
On this day, the crew is working with a prototype dummy meant to simulate a 10-year-old child. It has sensors inside and outside. It is in a standard car seat, as well as a booster seat, and is strapped in with a seat belt.
A dozen high-speed cameras ring the simulated car interior, which sits on an accelerator sled. Each camera has been precisely aimed and calibrated; if anyone bumps the tripod holding one of the cameras, it’s back to square one.
“We have to make sure everything goes off at the same time,” said fellow research technologist Katie Konkel.
Instead of ramming the sled into a wall, the sled is pushed backward with the identical force of a 35 mph crash, using compressed air.
“It basically is a crash in reverse, of a car hitting a wall,” said Hans Hauschild, senior research engineer. “It’s the same response.”
High-intensity lights flood the chamber as the countdown begins. When the moment arrives, the thruster punches the sled down the track.
And it’s over.
“That whole thing takes 0.1 of a second,” Amato said.
The result: The dummy, which had been facing forward, is now facing sideways, its arms and legs akimbo.
All those sensors and all the video footage feed into computers, which produce data sets, charts and graphs. The video, shot at 1,000 frames a second, shows the impact in super slow motion, from numerous angles.
“We spend days or weeks setting up all these tests, and the data itself is a fraction of a second. And analysis of that data will take days or weeks,” Amato said.
Seat belt’s effect
The researchers are particularly interested in how the body interacts with the seat belt upon impact.
What they are seeing is the waist belt thrusting up into the abdomen – specifically the anterior superior iliac spine, or ASIS – near the pelvis, which could lead to significant damage to internal organs.
“When we start to recline seats, that’s when we see that belt ride up, and that’s not a good thing,” Pintar said, though he noted during this particular test, with the dummy in a more upright position, “it looks like the belt really did its job pretty well.”
They’re also interested in the effect of booster seats, noting that parents start to consider eliminating the booster when a child gets to be about 10 years old.
“One of the advances in this particular dummy is that it has extra sensors, not only in the pelvis, but also the abdomen,” Pintar said.
And while these tests use a dummy simulating a 10-year-old child, Pintar said the results can be applied to adults as well.
“It’s the same problem: It’s belt fit; it’s reclined posture. It’s all of that,” he said.
Testing the dummy
While the tests are gauging the effects of the crash on a 10-year-old child, they are also testing the dummy itself, which is known as an LOCD – large omnidirectional child dummy.
“This is all cutting edge. It’s the first time this (dummy) has been used in this application,” Hauschild said.
“By using this newer dummy, we can get better data,” Amato said, noting that the dummy also uses technology similar to what is used in motion-capture videography.
“They can see how everything moves in 3-D space. It’s pretty cool,” he said.
“That’s really part of the story here – trying to figure out in these reclining positions whether this dummy can sense it appropriately,” Pintar said, noting the dummy better mimics compression of the chest and the effects of crashes on clavicles.
After the test, the techs examine the dummy, the sled and everything else and start readying for the second test, which will be without the booster seat.
It will take hours to set up the next test; on a good day, three tests can be run, the techs said, though two is typical. That speaks to the painstaking attention to detail to make sure everything is perfect before a test takes place.
“It’s very tedious, but it’s very important to pay attention to detail,” Hauschild said.