Mussels offer insight for quake-proofing

00:12, Jul 26 2013

Research that has solved the puzzle of how mussels cling to a surface as they are buffeted by powerful waves could offer insights for building in earthquake-prone areas.

Unlike other species, such as barnacles, mussels dangle at a distance from the rock or surface they are connected to, attached by a collection of fine filaments called byssus threads - the threads are the beard removed before mussels are eaten.

By using the threads, mussels can drift and take in nutrients, although they are at risk from crashing waves.

The Massachusetts Institute of Technology said the secret to the tiny bungee cords had been unravelled by MIT research scientist Zhao Qin and professor of civil and environmental engineering Markus Buehler.

Their findings are published in the journal Nature Communications. They found that about 80 per cent of the length of the byssus threads were made of stiff material attached to the rock or other surface.

The remaining 20 per cent was a softer stretchy material connected to the mussel.


In the dynamic, sloshing environment of waves and currents, mussels could withstand impact forces nine times greater than the forces exerted by stretching in only one direction.

"Such an efficient, yet simple, architecture has clear application in inspiring artificial designs where energy absorption is required, with one possible example being for the design of structures in earthquake-affected zones."

The researchers found the distribution of stiffness along the threads was key. The precise ratio of 80 per cent stiff and 20 per cent softer stretchy material may be critical, enabling mussels to rapidly dissipate impact energy.

Dynamic loading - forces such as waves that move or change when acting on a structure - could be treacherous for engineered and natural systems because the force could easily become extremely large, leading to catastrophic failure.

"For example, forces on a building's pillars during earthquakes or explosions reach several times that of its static weight," the researchers said. Fairfax NZ

The Marlborough Express