Protection built to scale -- fish scale, that is

Jul 27, 2008
Polypterus senegalus is a primitive fish whose scaly armor has yielded clues to MIT researchers seeking to better protect soldiers of the future. Photo courtesy / Christine Ortiz

(PhysOrg.com) -- Scientists seeking to protect the soldier of the future can learn a lot from a relic of the past, according to an MIT study of a primitive fish that could point to more effective ways of designing human body armor.

The creature in question is Polypterus senegalus, a fish whose family tree can be traced back 96 million years and who still inhabits muddy, freshwater pools in Africa. Unlike the vast majority of fish today, P. senegalus sports a full-body armored "suit" that most fish would have had millions of years ago--a throwback that helps explain why it is nicknamed the "dinosaur eel."

It was known that the fish's individual armored scales were comprised of multiple material layers--each of them about 100 millionths of a meter thick. But in a U.S. Army-funded study carried out through the MIT Institute for Soldier Nanotechnologies and published in the July 27 online issue of Nature Materials, a team of MIT engineers unraveled exactly how the layers complement one another to protect the soft tissues inside the fish body--particularly from a penetrating biting attack. P. senegalus is known to be territorial and attack members of its own species that are of similar or smaller size.

Specifically, the team used nanotechnological methods to measure the material properties through the thickness of one individual fish scale--about 500 millionths of a meter thick--and its four different layer materials. The different materials, the geometry and thickness of each layer, the sequence of the layers and the junctions between layers all contribute to an efficient design that helps the fish survive a penetrating attack such as a bite.

This research will help to better understand the relationship between a specific threat and the corresponding design of a protective armor, the team said.

"Such fundamental knowledge holds great potential for the development of improved biologically inspired structural materials, for example soldier, first-responder and military vehicle armor applications," said lead author Christine Ortiz, an associate professor in MIT's Department of Materials Science and Engineering.

"Many of the design principles we describe--durable interfaces and energy-dissipating mechanisms, for instance--may be translatable to human armor systems," Ortiz added.

One way in which the researchers tested the fish armor was by experimentally mimicking a biting attack on top of an individual scale that had been surgically removed from a living fish. The team found that the design of the P. senegalus armor kept the crack localized by forcing it to run in a circle around the penetration site, rather than spreading through the entire scale and leading to catastrophic failure, like many ceramic materials.

This study was carried out in collaboration with co-author Professor Mary Boyce, chair of MIT's Department of Mechanical Engineering. The study has two first authors: Benjamin Bruet, a former member of Ortiz's lab who recently received a PhD in materials science and engineering from MIT, and Juha Song, a joint doctoral student between Ortiz and Boyce.

Provided by MIT

Explore further: Thinnest feasible nano-membrane produced

add to favorites email to friend print save as pdf

Related Stories

Unlocking secrets of new solar material

11 hours ago

(Phys.org) —A new solar material that has the same crystal structure as a mineral first found in the Ural Mountains in 1839 is shooting up the efficiency charts faster than almost anything researchers have ...

Recommended for you

Thinnest feasible nano-membrane produced

Apr 17, 2014

A new nano-membrane made out of the 'super material' graphene is extremely light and breathable. Not only can this open the door to a new generation of functional waterproof clothing, but also to ultra-rapid filtration. The ...

Wiring up carbon-based electronics

Apr 17, 2014

Carbon-based nanostructures such as nanotubes, graphene sheets, and nanoribbons are unique building blocks showing versatile nanomechanical and nanoelectronic properties. These materials which are ordered ...

Making 'bucky-balls' in spin-out's sights

Apr 16, 2014

(Phys.org) —A new Oxford spin-out firm is targeting the difficult challenge of manufacturing fullerenes, known as 'bucky-balls' because of their spherical shape, a type of carbon nanomaterial which, like ...

User comments : 10

Adjust slider to filter visible comments by rank

Display comments: newest first

NightfallSentry
3.7 / 5 (3) Jul 27, 2008
Can anyone say Dragonskin!?!
I guess we will just ignore that little issue.
Suzu
5 / 5 (2) Jul 27, 2008
My black dragonscale armor is plus 9!
Arikin
3 / 5 (2) Jul 27, 2008
96 million years for the animal to develop it. Wonder how long the Pentagon will take? :-)
zevkirsh
3 / 5 (2) Jul 28, 2008
eels armour protects against biting not bullets.
z
CreepyD
5 / 5 (1) Jul 28, 2008
Yes but a bite can have a LOT of force behind it.. and a tooth is a similar shape to a bullet.
Obviously it would be adapted.. Hopefuly it will be less elusive to copy that spider silk.
KB6
not rated yet Jul 28, 2008
It would be nice to have flexible body armor able to stop knives and bayonets as well as bullets.
Eco_R1
5 / 5 (2) Jul 28, 2008
but nothing can withstand the power of a chuck norris round house kick, not even with a spider silk bomb jacket and a Polypterus senegalus scale tower shield.
Eco_R1
not rated yet Jul 28, 2008
oh and on a more serious note, if you were to wear a normal "flexible" garment made out of spider silk, it would not stop the bullet, it would just cover it while still entering the body.
earls
not rated yet Jul 28, 2008
At least the bullet will be easy to get out. ;) A boot heel on the other hand...
Mercury_01
5 / 5 (1) Jul 28, 2008
Chuck norris doesnt rebove the bodies whos asses are wrapped around his boot heels. He simply walks them off.

More news stories

'Exotic' material is like a switch when super thin

(Phys.org) —Ever-shrinking electronic devices could get down to atomic dimensions with the help of transition metal oxides, a class of materials that seems to have it all: superconductivity, magnetoresistance ...

Innovative strategy to facilitate organ repair

A significant breakthrough could revolutionize surgical practice and regenerative medicine. A team led by Ludwik Leibler from the Laboratoire Matière Molle et Chimie (CNRS/ESPCI Paris Tech) and Didier Letourneur ...

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...