New Soft Helmet Turns Hard in Crash

Bill Christensen

Date: 04 December 2005 Time: 05:02 AM ET

Researchers at the University of Hertfordshire have discovered a complex elastomeric compound they call d3o that is both soft and hard.

The Ribcap is seen above. Below, the d3o 'ribs' in the cap.

A shear thickening material, it is flexible when moved slowly, but when it is compresssed by an impact, its molecules lock together. The material stiffens, spreading the impact over a greater area. The Swiss company Ribcap is bringing out a new line of headgear for snowsports based on this material. The Ribcap is a combination soft, flexible beanie and tough helmet.

After five years of development, the Ribcap team settled on d3o as the material of choice. Ruth Gough, d3o's brand manager describes her own experience using the Ribcap while out on the piste:

... she [Gough] had a rather dramatic fall that terminated on her head. "I was a bit dazed, and I almost wasn't sure whether I had actually hit my head, although the concern I got from those who saw it assured me that I really had, and quite hard!"
This is a common reaction to real world d3o impact trials. d3o is so comfortable it feels like an extension of you. It's very easy to forget it's there, and you'd be forgiven for thinking, in that split second before you hit the ground "this is never going to work..."
(From d3o technology and Ribcap [pdf])

In their 1971 novel The Flying Sorcerers, David Gerrold and Larry Niven write about an impact suit with similar properties:

"It was my impact suit," Purple said. He took a step forward and thumped himself hard in the belly with this fist. His belly was big and soft, so the blow should have made him wince. It did not. I thought for a moment that Purple had become rigid as stone.
"My impact suit," he repeated. "Normally it flows like cloth, but under a sharp blow it becomes a single rigid unit.
(Read more about Gerrold and Niven's impact suit)

Read more about these kinds of materials in Liquid Armor In Two Flavors: Shear Thickening and Magnetorheological or read about other uses for d3o. Thanks to Winchell Chung for contributing the tip for this article.

(This Science Fiction in the News story used with permission from Technovelgy.com - where science meets fiction.)

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