A design found in insect exoskeletons has led researchers from Monash University towards finding a more durable, safe, and environmentally friendly cement construction alternative.
The team of Monash University researchers was led by ATSE Fellow and structural engineer Professor Wenhui Duan FTSE.
Many insect exoskeletons are both strong and capable of absorbing a lot of energy, making them damage resistant. Inspiration from this damage-resistant combination has allowed Professor Duan to develop a new material design concept.
These structures, called design motifs, are valuable sources of inspiration for modern materials design and aid the fabrication of fit-for-purpose materials. Until now, only eight categories of design motifs have ever been extracted and adopted in materials design.
The new design motif, discovered by Professor Duan’s team, adds to the eight known and common biological structural design patterns. This particular design has the potential to add a high strength motif to commonly used building materials such as composites and cement.
This damage-resistant structure has been identified in the exoskeletons of anthropods and the legs of mammals, amphibians and reptiles.
Brittle materials, including concrete, are often strong and durable but can be easily broken when put under the pressure of weight and can weaken as a result of corrosion and degradation. If only a small area of concrete becomes cracked, the whole structure can quickly fail as it doesn’t change shape when loaded with weight.
The mechanism found by Professor Duan in insect exoskeletons can be used to develop a strong but energy absorbing material.
"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 its load-bearing capacity."
This allows for controllable damage and ensures that if damage does occur, around 80% of the structure can still maintain its integrity.
Solidifying environmental impact
The discovery of this new material will assist in reducing the use of cement through improving damage tolerance.
The cement industry is one of the largest producers of carbon dioxide, creating up to 8% of worldwide human-made emissions of the gas. This is due to engineers often using up to 30% more material than technically required to ensure maximum safety within a structure.
As this new material design provides a stronger and safer alternative to traditional materials, the volume of cement, and consequentially carbon dioxide emissions, can be reduced.
Professor Duan hopes this research breakthrough will inspire more interest in civil engineering, which is typically seen as low-tech and perhaps less exciting than other engineering disciplines.
Read the Monash University media release for more information.