Imma Perfetto
Cosmos science journalist
A sea sponge skeleton made of glass has engineers wondering how it might improve building materials.
The sponge in question lives at the bottom of the Pacific Ocean, and is known as Venus’ flower basket (Euplectella aspergillum). It builds its intricate basket-like skeleton out of silica – the main material in sand and glass.
The skeleton’s lattice pattern has inspired Australian engineers to develop a new material with incredible compressive strength and stiffness.
It’s known as an “auxetic” material, meaning it contracts when compressed.
“While most materials get thinner when stretched or fatter when squashed, like rubber, auxetics do the opposite,” says Dr Jiaming Ma of RMIT University, lead author of a study describing the new material in the journal Composite Structures.
“Auxetics can absorb and distribute impact energy effectively, making them extremely useful.”
Ma and the team from RMIT’s Centre for Innovative Structures and Materials modelled their double lattice design on the sea sponge. It forms a uniform square grid further reinforced by 2 sets of diagonal struts.
They tested the design using computer simulations and a 3D printed sample made from thermoplastic polyurethane and found the lattice is 13 times stiffer than existing auxetic materials.
It can also absorb 10% more energy while maintaining its auxetic behaviour, compared to existing designs.
The material’s remarkable properties could be used to improve architecture and the manufacture of certain products.
“Our auxetic metamaterial with high stiffness and energy absorption could offer significant benefits across multiple sectors, from construction materials to protective equipment and sports gear or medical applications,” says Dr Ngoc San Ha of RMIT, corresponding author of the study.
They now plan to produce steel versions of the design to test with concrete and rammed earth structures – a construction technique using compacted natural raw materials.
“We’re developing a more sustainable building material by using our design’s unique combination of outstanding auxeticity, stiffness, and energy absorption to reduce steel and cement usage in construction,” says Ma.
“It’s auxetic and energy-absorbing features could also help dampen vibrations during earthquakes.”
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The Ultramarine project – focussing on research and innovation in our marine environments – is supported by Minderoo Foundation.