Animal exoskeletons could lead to stronger construction materials

Researchers from Monash University have found a new pattern derived from animal exoskeletons that could create more durable materials for building and construction.

In a paper published in Nature Communications, Professor Wenhui Duan from the Department of Civil Engineering at Monash University said the new pattern can add a high strength motif to commonly used building materials such as composites and cement, and may help reduce carbon emissions.

The cement industry is one of the largest producers of carbon dioxide, creating up to 8 per cent of worldwide man-made emissions of this gas.

This discovery could help reduce the use of cement by improving the material’s damage tolerance.

The research team replicated the design motif using cement material. In combination with a 3D printing technique, nanotechnology and artificial intelligence, the team was able to fabricate a lightweight cement composite which demonstrated a 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. In addition, this design motif can also be applied to various materials such as ceramic, glass, polymeric and metallic materials for advanced materials design, energy storage/conversion and architectural structures, in collaboration with the teams from the University of Queensland and the University of Manchester,” Duan said.

Since the 1972 discovery of the helical structure, one of the most common structural patterns in biology, there has been a drive to extract design motifs to aid the fabrication of structural materials.

After almost 50 years of research, remarkable repetitions have been confirmed in most classes of species but only eight categories of design motifs have ever been extracted and adopted in materials design, until now.

The new design structure has been identified in various species such as the exoskeletons of arthropods, the legs of mammals, amphibians and reptiles.

These design motifs are valuable sources of inspiration for modern materials design and aid the fabrication of structural material.

“Compared to the current design motif, our segmental design motif dissipates the energy by segment rotation. The beauty of our discovered design 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 (around 80 per cent) of load-bearing capacity,” Duan said.

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