New insights洞察力,眼力 about a tiny snail蜗牛 that lives on the ocean floor could help scientists design better armor for soldiers and vehicles, according to MIT麻省理工学院 researchers. A team of materials scientists, led by MIT Associate Professor Christine Ortiz, report that the shell of the so-called "scaly有鳞的,积垢的-foot" snail1 is unlike any other naturally occurring or manmade armor. The study suggests that its unique three-layer structure dissipates浪费,驱散 energy that would cause weaker shells to fracture破裂,断裂.
Copying various aspects of the structure could help scientists design better armor for military use, says Ortiz, who is a member of MIT's Institute for Soldier Nanotechnologies. The new study was partly funded by the Army and the Department of Defense3 and will appear in the Proceedings4 of the National Academy of Sciences the week of Jan. 18.
Ortiz' attention was drawn5 to this interesting gastropod腹足类动物 in 2003, when its discovery was first reported. The snail lives in a relatively6 harsh粗糙的,严厉的 environment on the floor of the Indian Ocean, near hydrothermal热水的 vents8 that spew喷涌,呕吐 hot water. Therefore it is exposed to fluctuations10变动,波动 in temperature as well as high acidity酸度,酸性, and also faces attack from predators食肉动物,捕食者 such as crabs13 and other snail species.
When a crab14 attacks a snail, it grasps the snail's shell with its claws and squeezes it until it breaks — for days if necessary. The claws generate mechanical energy that eventually fractures the shell, unless it is strong enough to resist.
In the new paper, Ortiz and her colleagues, including MIT Dean of Engineering Subra Suresh, report that the shell of the hot vent9 gasotropod has several features that help dissipate mechanical energy from a potential penetrating15 predatory食肉的,掠夺的 attack. Of particular importance is its tri-layered shell structure, which consists of an outer layer embedded植入的,内含的 with iron sulfide硫化铁 granules颗粒, a thick organic middle layer, and a calcified17钙化的 inner layer.
Most other snail shells have a calcified layer with a thin organic coating on the outside.. In the scaly2 foot gastropod, simulations suggest that the relatively thick organic middle layer can absorb much energy during a penetrating attack. It may also help to dissipate heat and thermal7 fluctuations exhibited near hydrothermal vents.
How they did it: Ortiz and her colleagues measured the mechanical properties of the snail shell using a machine called an indenter硬度计压头, which has a diamond tip. By measuring the force applied18 to the shell, and the shell's resulting displacement19, they can calculate its mechanical properties.
Next steps: Ortiz is looking at host of natural exoskeletons外骨骼 in order to extract protective design principles, including chitons石鳖, urchins海胆, beetles21甲壳虫, and armored fish.