Page 19 - Biomimetics : Biologically Inspired Technologies

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Introduction to Biomimetics 5

Figure 1.1 The image of the Egyptian God Khensu with wings (left) illustrates the age-old fantasy of humans of
being able to fly. (Photographed by the author at the Smithsonian Museum, Washington, DC.) This fantasy turned
to reality with the use of aerodynamic principles leading to enormous capabilities such as the supersonic passenger
plane, the Concord on the right. (Photographed by the author at the Boeing Aerospace Museum, Seattle,
Washington.)

use of the terms intelligent or smart suggests the emulation of biological capabilities with a certain
degree of feedback and decision making. Other terms include aging, fatigue, death, digestion, life
cycle, and even ‘‘high on the food chain’’ (referring to a high management level). In the world of
computers and software many biological terms are used to describe aspects of technology including
virus, worm, infection, quarantine, replicate, and hibernate. Other forms of imitating nature
comprise virtual reality, simulations and copying of structures and materials. Shapes are also
used as recognizable terms where the dog-bone provides a clear description of the shape of test
coupons that are used to measure the tensile module and strength of materials. Structures are also
widely copied, for example the honeycomb. Used for its efficient packing structure by bees (which
is different from its use in aerospace — for low weight and high strength), the honeycomb has the
same overall shape in both biological and aerospace structures. It could be reasoned that the
honeycomb structures, which are used in many of the aircraft structures of today’s airplanes,
were not copied from the bees (Gordon, 1976). However, since it is a commonly known structure
invented by nature many years before humans arrived, no patent can be granted in the ‘‘patent
court’’ of nature to the first human who produced this configuration. Generally, biological materials
(Chapter 14), including silk and wool that are widely used in clothing, have capabilities that surpass
those made by humans. This superb capability of biological materials, structures, and processes has
been the subject of imitation in artificial versions of materials.
Plants can also offer a model for imitation (Chapter 19). Besides their familiar characteristics,
some plants exhibit actuation capabilities that are expected of biological creatures. Such plants
include the mimosa and the Sensitive Fern (Onoclea sensibilis) that fold or close their leaves
when touched (Figure 1.2). There are also bug-eating plants with a leaf derived trap ‘‘door’’
that closes and traps unsuspecting bugs that enter to become prey. Examples of such plants include
the Venus Flytrap (Dionaea muscipula) and the Pitcher plant (Sarracenia purpurea) (Figure 1.3).
The sunflower tracks the sun’s direction throughout the day to maximize exposure to its light. Plants
have evolved in various ways, and some have produced uncommon solutions to their special needs.
For example, some desert plants have flowers that produce the malodor of rotten meat, and some
even have a brown color that appears very much like decomposing meat. Such characteristics are
critical for these plants to attract flies, rather than bees, to pollinate their flowers.