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News Clippings
7/1/99 Daily Telegraph
Old Nature can still teach us a trick or two
Long ignored by the technocrats, biology is now
proving to be rich in engineering solutions. Michael
Fitzpatrick reports
IN the quest for design perfection, engineers and
designers are turning to an expert who's been around for
a few billion years - Nature. Mother knows best, after
all, although scientists have been reluctant to admit it
in the past.
" 'Biology has not quite got it right' was the
prevalent thinking," says biologist Dr Julian
Vincent, a co-director for the Centre for Biomimetics at
Reading University, and champion of biomimicry.
"Where nature might put curves, in a bone for
example, an engineer would be happier reaching for his
ruler and straightening it out."
Following centuries of distrusting nature and repeated
attempts to master her, some scientists, technologists
and engineers (with a little hi-tech cajoling) are now
hoping she will reveal the secrets of what are seen as
highly successful, low-energy-dependent designs. The
result is the emerging science of Biomimetics, which, by
using up-to-date analytical techniques, is helping put
some of nature's better ideas to work in industry.
Engineers have been adept at synthesising a range of
extremely useful materials. But they could do better.
Kevlar, for example, is a remarkably strong fibre used in
aeronautics and to make bullet-proof vests. It is made by
applying considerable pressure to petroleum products
heated to 1,400F.
To a spider the process would seem a trifle hyperactive.
Without using anything like that kind of heat, spiders
produce a material that's 10 times stronger than an
equivalent-sized steel wire - and it's biodegradable.
Clearly, a synthetic equivalent of spider thread would be
of enormous benefit. Biomimetics could help scientists
create it, not by copying it exactly but by incorporating
some of nature's design aspects.
Other muses proving particularly inspirational include
subjects as diverse as sea cucumbers, mushrooms, hedgehog
spines and even our own bones.
Working for the first time with biologists such as
Vincent, engineers are finding the answers to technical
and design problems that have eluded their slide rules in
the past. The knowledge biologists have gleaned from
mechanics in the natural world can be particularly
helpful when struggling to find the optimum design, says
Vincent. "We have the tools for analysing biological
systems to a sufficiently deep level. And the tools and
material science for recreating some of those ideas at a
sufficiently deep level so that the transfer of
technology is possible."
These latest methods include microscopy techniques, the
theory of understanding materials, fracture mechanics,
and composite theory.
All these are coming together, says Vincent, to make the
application of biomimetics a practical reality.
Among those seeking enlightenment via the arts of
biomimicry is the British defence industry, which has
been looking for a better aircraft design for years.
Could Vincent find something in nature that might improve
the performance of military jets? Consider the sea
cucumber, suggested the professor.
Studies of this seabed-dwelling creature have revealed a
skin which the animal can stiffen, soften and stiffen
again. The same design would be useful in creating a
reconfigurable airfoil using materials based on those in
the skin of the sea cucumber, says Vincent.
"It's a matter of seeing how a sea cucumber does it
with its organic matrix and adapting that for use by
transferring those ideas to, say, using carbon
fibre."
Engineers also have a lot to learn from wood (energy
efficiency and load-bearing), shells (toughness), and
antler bone (toughness, again - tougher than any man-made
composite).
"What nature can teach us best," says Vincent,
"is that we don't need terribly hi-tech materials
but have to be more careful about the design. Cellular
materials in particular are nature's forte."
Hedgehogs, for one, benefit from some subtle cellular
engineering. The spiny hedgehog has the unique ability to
drop from a relatively high place and bounce away safely
on its quills. Hedgehogs' spines work so well because
even though they show a coarser honeycomb structure than,
say, the foam-like make-up of porcupine quills or plant
stems, they are perfect for absorbing shocks. And,
because of its weight-energy cost efficiency the hedgehog
principle could be exploited for designing lightweight
structures such as space stations, says Vincent.
More down-to-earth matters have engineers seeking a
material that is tough but not brittle. Nature offers
mother of pearl, or nacre, which is 500 to 3,000 times
tougher than the chalk that constitutes 95 per cent of
its bulk.
Bill Clegg, a professor of materials at Cambridge
University, has made a close study of nacre: "I was
looking at cheap ways of making toughened ceramics. The
major problem is that they are difficult to make, and
expensive. I found that the layered nature of nacre had
excellent qualities of toughness and only bent under
extreme pressure."
Using puff pastry technology, Clegg has developed a
ceramic that has superior qualities of heat-resistance,
toughness and, like its sea-shell equivalent, the ability
to deflect cracks. Daimler, and Volvo Aerospace have
helped to build Clegg's samples, which he says will be
perfect for pouring molten steel. The development of
jet-engine components has also benefited from Clegg's
work in biomimetics.
But although the science of mimetics might be new, the
use of nature-inspired designs is not. Earlier successes
include the Crystal Palace and the Eiffel tower.
That Gustave Eiffel's wrought-iron structure resembles a
huge, upturned peg-leg is no fluke. Inspired by the
architecture of the human thighbone, its creator was
originally fired by the work of Hermann von Meyer, a
professor of anatomy at Zurich who unravelled the secrets
of the way the femur efficiently carries off-centre
loads. Mathematician and engineer Karl Cullman translated
Von Meyer's findings into applicable theory and the
mathematical model lead to the design of the Paris tower.
Designed for the Great Exhibition of 1851, Joseph
Paxton's glass roof for his crystal palace was also a
triumph of design by nature's example. A botanist by
profession, Paxton grew the large water lily Victoria
amazonica with leaves more than a metre across. He had
noticed that the plant's intricate rib-like structure
supported the great weight of each leaf. He borrowed the
same principle for his palace.
Another plant, the prickly burdock, is probably one of
the world's most successfully mimicked designs. With it
forever getting caught in his dog's coat, it occurred to
Belgian inventor Georges de Mestral that the same action
would be a good way of joining two fabrics together.
Velcro was the result.
In the coming "Age of Materials", engineers
will be increasingly on the look-out to poach from
biology, says Clegg.
"Some biologists find idea of biomimetics
unacceptable, because in a lot of ways what we do is much
cruder. We are not actually trying to copy faithfully, we
were not trying to produce a shell, for example. What you
see is something that has that property in the natural
structure. Biomimetics is a fund of ideas."
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