Exoskeleton find leads to super cement

| April 17, 2022

Australian researchers have extracted a new design motif from the rigid external coverings of invertebrates that could help create more damage-tolerant construction materials.

Monash University structural engineer Wenhui Duan says the pattern, an addition to eight established biological designs, delivers greater strength to commonly used materials like composites and cement.

He also believes it might help reduce carbon emissions.

With the cement industry creating up to eight per cent of man-made CO2 emissions worldwide, it’s hoped the discovery will mean a cutback in its use by improving damage tolerance.

Professor Duan and his team replicated and applied their design by adopting a 3D printing technique combined with nanotechnology and artificial intelligence.

The result was superior load-bearing capacity and a unique progressive failure pattern.

“We demonstrated the application of this design motif in producing a high strength, damage tolerant lightweight cement material,” he said.

With collaboration from the University of Queensland and University of Manchester, he was also able to show the same outcome can be achieved with ceramic, glass, polymeric and metallic materials.

Since the 1972 discovery of the helical structure, one of the most common in biology, there has been a drive to extract designs from more than seven million living species to aid the fabrication of materials.

Remarkable repetitions have been confirmed in most classes of species but only eight categories of design have been extracted and adopted, until now.

Among others, the new structure has been identified in the exoskeletons of arthropods, the legs of mammals, amphibians and reptiles.

“Compared to the current design motif, our segmental design motif dissipates the energy by segment rotation,” Prof Duan explained.

“The beauty of our discovered motif is that the material can exhibit a unique periodic progressive failure behaviour.

“It means we can contain the damage within a particular region of material, while the rest of the structure can still maintain the integrity and most of load-bearing capacity.”