October 27, 2011
Can A Better Helmet Be Designed From Studying Woodpeckers?
Researchers studying woodpeckers could learn to develop more effective helmets that could protect the human head more effectively.
Able to peck at a tree trunk at 6-7 meters per second results in intense deceleration forces upon impact, but woodpeckers do so every day without sustaining any brain injury. Scans of the birds´ skulls detail micro-structural parameters such as bone volume, thickness, and density of the species.
Investigating the source of this protection, Yubo Fan of Beihang University in Beijing and Ming Zhang of Hong Kong Polytechnic University, recorded the birds pecking for food using two synchronous high-speed video cameras. The heads of the birds, pecking at 6-7 meters per second, were found to decelerate at more than 1,000 times the force of gravity.
Also, their brains are longer top-to-bottom than front-to-back, spreading what movement there is over a larger brain area, reports Jason Palmer of BBC News.
The team first had a look at woodpeckers in a controlled environment with high-speed cameras capturing images of the birds striking a force sensor that measured pecking power. This revealed that the birds slightly turn their heads as they land a blow, influencing how forces are transmitted.
The study published in PloS ONE reveals x-ray and computer simulations of the birds skulls showing three primary factors at work in sparing the birds injury. The birds have a looping structure around the whole skull acting as a “safety belt”, especially after the initial impact.
Secondly, the team found that the upper and lower halves of the beaks were uneven and forces transmitted from the tip of the beak into the bone lowered the load that made it as far as the brain.
Lastly, plate-like bones with a “spongy” structure at different points in the skull helped distribute the incoming force, thereby protecting the brain. The team stresses that it is the combination of the three, rather than any one feature, that keeps woodpeckers pecking without injury.
Combinations of these features may be useful in guiding design for new protective gear for humans.
On the Net: