Page 34 - Biomimetics: Technology Imitates Nature

Biomimetics: Technology Imitates Nature

The Second World War's
Mosquito aircraft, which so far have
shown the greatest tolerance to dam-
age, were made by gluing dense ply-
wood layers between lighter strips of
balsa wood. The hardness of wood
makes it a most reliable material.
When it does break, the cracking takes
place so slowly that one can watch it
happen with the naked eye, thus giv-
ing time to take precautions. 30
Wood consists of parallel
columns of long, hollow cells placed
These materials, modeled on the struc- end to end, and surrounded by spirals
ture of wood, are believed to be suffi- of cellulose fibers. Moreover, these
ciently strong to be used in bullet-proof
cells are enclosed in a complex poly-
vests. (Julian Vincent, “Tricks of
Nature,” New Scientist, 40.) mer structure made of resin. Wound
in a spiral, these layers form 80% of
the total thickness of the cell wall and, together, bear the main weight.
When a wood cell collapses in on itself, it absorbs the energy of impact by
breaking away from the surrounding cells. Even if the crack runs between
the fibers, still the wood is not deformed. Broken wood is nevertheless
strong enough to support a significant load.
Material made by imitating wood’s design is 50 times more durable
than other synthetic materials in use today. 31 Wood is currently imitated
in materials being developed for protection against high-velocity parti-
cles, such as shrapnel from bombs or bullets.
As these few examples show, natural substances possess a most in-
telligent design. The structures and resistance of mother-of-pearl and
wood are no coincidence. There is evident, conscious design in these ma-

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