A team of researchers in Europe has shown that the density
of large structures can be dramatically reduced, if they are designed using a
fractal pattern. The researchers have worked out a way to calculate an optimal
“hierarchal structure” built from a certain material so that it can withstand a
given load. They claim that using such techniques could help in building highly
efficient load-bearing structures that could be used in solar sails, cranes or
other lightweight-yet-strong constructs.
A fractal is an object or a structure that is self-similar
on all length scales. Fractal patterns are seen in nature at all scales –
everything from a single fern leaf that resembles the entire plant, to clouds,
snowflakes, blood vessels and cauliflowers shows a fractal pattern. A
particular example that inspired this latest work is trabecular bone – the
“spongy” bone that is found near joints in the human body. This bone has a
sponge-like network of fibres that have a pseudo-fractal pattern, whereby the
pattern is almost self-similar across a few scales. This makes the bone strong
but light and capable of providing the necessary strength and stiffness.