Woodpeckers hammer their beaks against tree trunks 22 times per second--without injury. It's no wonder scientists have based the design of a new impact-absorbing device on the structural and material properties of the bird's head.
Sungmin Park and Sang-Hee Yoon. mechanical engineers at the University of California, Berkeley, studied the golden-fronted woodpecker to learn how the birds bore holes through wood to find insects without hurting themselves. The scientists identified several "systems" in the bird's skull that protect its brain. They re-created them in their shock absorber (see diagram, below).
"Improved shock-absorbing designs can help protect things subject to sudden, rapid stops, such as Formula 1 race cars and sports helmets," says Yoon.
The parts of a woodpecker's skull (inset, top) are color-coded to match their corresponding parts in a new shock absorber (inset, bottom).
BRAIN/ELECTRONICS: A woodpecker's skull protects its fragile brain from impacts. Similarly, the shock-absorbing device was designed to protect things like sensitive electronics.
BEAK/OUTER CASE: Just as the woodpecker's beak is rigid and strong, so is the shock absorber's steel casing.
SPRINGY BONE/ELASTIC LAYER: The woodpecker has a springy hyoid bone that supports its tongue and evenly distributes loads (forces on a structure). A rubber layer in the device works the same way.
SKULL/ALUMINUM LAYER: Cerebrospinal fluid cushions the bird's brain inside its skull. An extra layer of metal in the new shock absorber likewise cushions delicate internal parts.
SPONGY BONE/GLASS BEADS: A woodpecker has porous bone between its skull and beak, which absorbs low-frequency vibrations. Glass beads in the device serve a similar function.
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|Title Annotation:||BIOLOGY: BIOMIMICRY; shock absorbers design|
|Article Type:||Brief article|
|Date:||May 9, 2011|
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