Coconuts could show the way to make buildings quake-proof

In what has the potential to be a major breakthrough for scientists working to protect buildings from earthquakes and other natural disasters, researchers are using compression machines and an impact pendulum to investigate how coconuts disperse energy in their shells.

The word coconut is derived from the Spanish word 'coco' which means "head" or "skull" which is hard in nature, and the technology involved could help in the construction of earthquake resistant buildings, researchers say.

Researchers of Plant Biomechanics Group of the University of Freiburg are working with civil engineers and material scientists to investigate how the specialised structure of coconuts could help in making a building's walls as part of the larger project on 'Biological Design and Integrative Structures'.

In the latest study, researchers used compression machines and an impact pendulum to study how coconuts disperse energy.

''By analysing the fracture behaviour of the samples and combining this with knowledge about the shell's anatomy gained from microscopy and computed tomography, we aimed to identify mechanically relevant structures for energy absorption,'' said researcher Stefanie Schmier.

In their investigation they endocarp the layer which consists mainly of highly lignified stone cells and a ladder-like design which is thought to help withstand bending forces.

''The endocarp seems to dissipate energy via crack deflection,'' noted Schmier. ''This means that any newly developed cracks created by the impact don't run directly through the hard shell.''

According to the study the angle of vascular bundles helps to divert the route of cracks and thus makes the cracks stop before reaching the other side.

''The combination of lightweight structuring with high energy dissipation capacity is of increasing interest to protect buildings against earthquakes, rock fall and other natural or manmade hazards,'' concluded Stefanie.