Absorbing matter

A deceptively simple device could form the basis for a new generation of shock-absorbing safety systems for vehicles, sporting equipment — and even buildings.

Developed by Fayek Osman at the University of Bath, the device could be used as part of train buffers, aircraft undercarriages, car bumpers and other assemblies built to absorb sudden large impacts — and unlike the current technologies, it’s re-usable.

The device consists of a metal bar running through a curved channel. The bar is positioned so that its end faces the direction of impact. When the force arrives, it pushes the metal along the channel, forcing it to follow the curve. This pushes the other end of the bar out of the other side of the channel, so to re-use the device, it just has to be turned round.

‘It all depends on understanding how materials behave when they’re forced round corners,’ said Osman. ‘If you pump a fluid through a bent channel with a constant cross-section, it will just flow straight through. But metals are much cleverer than that — push them through a bend, and they don’t flow like liquids, but like solids. You have to overcome the binding energy between the atoms to deform the material, and to do that, you need to put in energy.’