Introducing the Gizmag Store

New blast-proof curtain gets thicker when stretched

By

June 24, 2010

The auxetic blast-proof curtain being put to the test

The auxetic blast-proof curtain being put to the test

Image Gallery (4 images)

OK, so first of all, how can a fabric possibly get thicker when stretched? Doesn’t that go against the laws of physics? Not, it turns out, when that material is auxetic. Cat skin and shin bones also apparently possess this quality. The University of Exteter, in collaboration with their spin-off company Auxetix Ltd, have developed an auxetic blast-proof curtain. If a bomb were to go off near such a curtain, the pressure wave would stretch the fabric outwards, thus thickening it and making it better able to hold back flying glass and other debris. The curtain is intended to be fitted over windows of buildings that are terrorist targets, or that are subject to events such as hurricanes.

Here’s how it works. Each strand of the curtain’s yarn consists of a central stretchy fiber, with a more rigid fiber wound around the outside of it. When put under strain, the rigid outer fiber straightens, squeezing the stretchy inner fiber and causing it to bulge out sideways – the inner fiber doesn’t actually expand, but it does end up taking up more space. Tiny pores open when the material stretches, which are too small to let debris through, but are sufficient to release some of the force of the blast, and keep the curtain from ripping.

A strand of the auxetic material

Variables such as the two fibers’ relative stiffness and diameter, along with the angle at which the outer fiber is wound, can have a marked effect on the performance of the material. The researchers are currently tweaking these parameters, to develop different curtains for different applications.

There is a range of widely-available types of fibers that are suitable, and conventional processes can be used for producing the yarn and weaving it into a textile. The material is just 1 to 2 millimeters thick, so it still lets in a reasonable amount of light.

The auxetic material in a relaxed (left) and stretched (right) state

The Exeter and Auxetix team see other possible uses for the material, including bandages, dental floss, and soil erosion barriers.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
Tags
1 Comment

Where does one obtain some of this fabric? email emicra8@aol.com

: )

Maureen Cragg
25th June, 2010 @ 03:31 pm PDT
Post a Comment

Login with your gizmag account:

Or Login with Facebook:


Related Articles

Just enter your friends and your email address into the form below

For multiple addresses, separate each with a comma




Privacy is safe with us because we have a strict privacy policy.

Looking for something? Search our 26,496 articles