New discovery in animal exoskeletons leads to advances in designing construction materials

In a paper published in Nature Communications, Professor Wenhui Duan from the Department of Civil Engineering at Monash University says the new pattern, adding to the eight known and common biological structural design patterns, 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% of worldwide human-made emissions of this gas; this discovery will assist in reducing the use of cement by improving the material's damage tolerance.

The research team replicated the design motif in cement material, one of the most consumed construction materials in the world. They adopted a 3D printing technique combined with nanotechnology and artificial intelligence to fabricate a lightweight cement composite which adopted this segmental design motif, demonstrating 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 University of Queensland and University of Manchester," says Professor Duan.

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 from more than 7 million living species in the world to aid the fabrication of structured/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%) of load-bearing capacity."