Canadian device precisely dampens load from collision impact

Ever since Mercedes-Benz patented the idea of crumple zones in the early 1950s, these energy absorbing systems have become a standard safety design feature. But while they have saved countless car occupants from suffering the full force of impact energy over the past 60 years, they do have limitations.

According to Dr. Bill Altenhof, associate professor in the University of Windsor’s Mechanical, Automotive and Materials Engineering Department, crumple zones don’t always deform in predictable ways, which leaves some uncertainty in pre-determining how effective the measures will be.

“The current systems typically depend on a collapsing, accordion-type deformation, which depends a lot on some very small imperfections or geometric incontinuities,” he says. “But if a small variation is introduced, because of the manufacturing or welding, they can lead to some pretty big differences.”

To remove chaos from these measures, Altenhof says he and his colleagues at the University of Windsor have created a simple device that provides a more predictable way to absorb impact energy. Shaped like a steel wheel with four spoke-like blades, the device could be built in to the end of a tubular aluminum frame. Upon impact, it cuts down into the frame tube, like a kitchen tool, causing the metal to spread rather than crumple unevenly.

“One of the first technicians that saw it said it was the world’s most expensive banana peeler,” he says. “While it does slice through materials, there is a lot of engineering behind it. When someone says that they need the load to be a specific value, we can engineer it so that the load is very close to that value. We can also ‘program’ into the device how its load deflection behaves.”

While vehicular applications for the device are evident, Altenhof says the device could be used in any situation where energy needs to be absorbed evenly and predictably, such as in buildings designed to withstand earthquakes.

“Give me any application where you need a way to optimize energy dissipation and load transfer resulting from impact or other traumatic events, and we can probably find a way to make this work,” he says.
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