RMIT University engineers unveil a super-strong material inspired by the Venus’ flower basket sponge. Combining remarkable stiffness and energy-absorbing capabilities, this innovation promises significant advancements in construction and various other fields.
Inspired by the intricate skeleton of the deep-sea sponge known as Venus’ flower basket, engineers at RMIT University have developed a revolutionary material boasting unparalleled compressive strength and stiffness. This new design, a double lattice structure, holds the potential to redefine architectural and product designs globally.
Led by Jiaming Ma, a post-doctoral researcher at the Centre for Innovative Structures and Materials (CISM) at RMIT, the team explored the unique properties of the Venus’ flower basket sponge, which thrives in the depths of the Pacific Ocean.
Their study uncovered the sponge’s skeleton’s remarkable blend of stiffness and strength, paired with an ability to contract under compression — a property known as auxetic behavior. Unlike traditional materials that get thinner when stretched or fatter when compressed, auxetics do the opposite.
“While most materials get thinner when stretched or fatter when squashed, like rubber, auxetics do the opposite,” Ma said in a news release. “Auxetics can absorb and distribute impact energy effectively, making them extremely useful.”
Auxetics are not entirely new; natural examples include tendons and cat skin, while synthetic auxetics have been used in expanding medical stents. However, their application has been limited due to low stiffness and energy absorption capacity — limitations that this new double lattice design effectively overcomes.
“Each lattice on its own has traditional deformation behavior, but if you combine them as nature does in the deep-sea sponge, then it regulates itself and holds its form and outperforms similar materials by quite a significant margin,” Ma added.
The team’s findings, published in Composite Structures, reveal that their lattice design is 13 times stiffer than existing auxetic materials, which are often based on re-entrant honeycomb structures. Remarkably, it also boasts a 60% greater strain range and can absorb 10% more energy.
Caption: The team’s double lattice structure (left) outperforms the standard re-entrant honeycomb design (right).
Credit: RMIT University
Ngoc San Ha, a lecturer in civil and infrastructure engineering at RMIT, emphasized the transformative potential of this bioinspired material.
“This bioinspired auxetic lattice provides the most solid foundation yet for us to develop next generation sustainable building,” he said in the news release. “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.”
One of the most immediate applications could be in the construction industry. The auxetic lattice structure has the potential to function as a steel building frame, reducing the need for excessive steel and concrete without compromising structural integrity. It could also pave the way for innovations in lightweight sports equipment, bulletproof vests and medical implants.
Mike Xie, an honorary professor of RMIT, hailed the project’s inspiration from nature, adding, “Not only does biomimicry create beautiful and elegant designs like this one, but it also creates smart designs that have been optimized through millions of years of evolution that we can learn from.”
Currently, the RMIT team has tested the design using computer simulations and 3D-printed samples made from thermoplastic polyurethane.
The next phase involves producing steel versions to integrate with concrete and rammed earth in construction projects. Ma hinted at the broader implications of their work.
“While this design could have promising applications in sports equipment, PPE and medical applications, our main focus is on the building and construction aspect,” Ma added.
“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,” he continued. “Its auxetic and energy-absorbing features could also help dampen vibrations during earthquakes.”
Additionally, the team plans to combine this innovative design with machine learning algorithms to create programmable materials, potentially ushering in a new era of highly optimized, smart materials.