Blast-proof curtains reduce impact of bomb explosions
27 Jul 2010 by Evoluted New Media
Blast-proof curtains which get thicker rather than thinner when stretched to provide better protection from the effects of bomb explosions is being developed by the University of Exeter and their spin-out company Auxetix.
Blast-proof curtains which get thicker rather than thinner when stretched to provide better protection from the effects of bomb explosions is being developed by the University of Exeter and their spin-out company Auxetix.
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Office buildings such as this could benefit from new blast-proof curtains |
The curtain is designed to remain intact and capture debris such as flying glass – which can cause severe and life-threatening injuries to those working or living in buildings near blast zones.
“In the 1995 Oklahoma City bombing, glass accounted for nearly two-thirds of all eye and head injuries,” said Professor Ken Evans, project leader, “The blast curtain we’re working on, which will be capable of dispersing shock from an explosion extremely effectively, will be backed up by robust scientific understanding vital to ensuring it can really block flying debris and achieve widespread use.”
The curtains are woven from two types of fibre – one stretchy, one stiff. The stretchy fibre forms the core of the yarn, while the stiffer fibre is wound around it. When under strain, the stiffer fibre straightens, which causes the stretchy fibre to bulge outwards, increasing the yarn’s diameter.
The yarn is known as an auxetic material because it gets thicker when stretched. The auxetic effect depends on the angle at which the second fibre is wound around the first and by the relative stiffness and diameter of the two fibres – by altering these, the yarn’s performance can be fine-tuned for different applications.
The curtains will let through some of the explosions shock waves – small pores open up when the material is stretched to reduce the force it is subjected to – but the pores are too small to allow any debris through.
The 1-2mm thick curtain is designed to fix over the inside of windows of buildings that are potential terrorist targets, while still behaving like normal curtains and letting light through. They are currently being tested in situations similar to car bomb explosions.
The project – funded by the Engineering and Physical Sciences Research Council (EPSRC) – could also develop fibres for smart, self-healing auxetic bandages, dental floss that expands when you pull it and in civil engineering to help reinforce soils for storm and floods.
