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A bomb-proof bag for safer skies

University of Sheffield

A flexible bag that stiffens under impact is being developed for use in luggage compartments of planes.

A soft, flexible bag that hardens when confronted with a sudden force could make air travel safer on all types of aircraft, according to researchers working on the novel bag for bags in the cargo bin.

The bag is being pitched as a less expensive, more flexible and lighter-weight alternative to hardened luggage containers deployed on some wide-body jets that protect passengers from explosives snuck onto planes.


Fundamental to the bag, named the Fly Bag, are a techy-sounding internal elastomeric coating and a fabric impregnated with a shear-thickening fluid, notes University of Sheffield in the UK, where the bag was developed in partnership with Blastech Ltd., a spinoff company owned by the university's lab.

Elastomers are low-stiffness, high-strain materials used in products such as adhesives and sealants. The bag has an elastomer developed to provide a heat- and flame-resistant gas seal in the bag at high strain rates and deformation.

Shear-thickening fluids increase in viscosity in response to impact. Simple STFs can be made by mixing together the right amount of corn flour and water. If rolled into a ball, this would bounce on hard surfaces but return to a fluid once left alone.

"Under normal circumstances, the particles in STFs repel each other slightly, however following sudden impact, the extra energy in the system proves stronger than the repulsive forces, causing the particles to clump together in structures called hydroclusters, which bump into each other, consequently thickening the fluid," a news release from the University of Sheffield explains.

For the Fly Bag, the research team coated the yarn of the fabric with STF. As the fabric comes under strain, shearing forces between the yarns cause the STF to thicken, temporarily increasing the stiffness of the fabric.

The same idea could be applied to body armor designed to protect people from knives and bullets, the team said, though their focus at the moment is air travel. The team hopes to have the first bags on the market within two years.

More on armor tech and travel safety:


John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).