Associate professor of mechanical and aerospace engineering Ashutosh Agrawal, Ph.D., is putting a newly-awarded $334,569 grant from the National Science Foundation toward the study of "Mechanics of Optimal Biomimetic Torene Plates and Shells with Ultra-High Genus".
Torenes are unique structures that resemble the nuclear envelope of a eukaryotic cell and have the potential to scale up into "lightweight shell structures for extreme mechanical environments."
Ordinary shell structures – rounded structural components with few to no joins – are an elegant solution to support large loads with relatively thin, lightweight construction in almost any size. Common man-made examples include bicycle helmets, airplane fuselages, and the Sydney Opera House.
Agrawal, however, believes that the torene shell structure may be an innovative solution for redesigning or reinforcing the shell structures we currently know and rely on.
So dubbed by Agrawal because they comprise "concentric shell layers fused via torus-shaped holes", torenes are a "novel geometric strategy" that exhibit one to two orders of magnitude greater flexural stiffness than corresponding solid cylinders and solid domes. These torene shell structures "could provide novel ways to design lightweight structures across length scales for countering extreme mechanical loads."
"Our findings are length-scale and material-properties independent, and therefore suggest that the torene architecture could be used to design lightweight shell structures for extreme environments in diverse set-ups," Agrawal explained.
"In civil and mechanical engineering, structures called I-beams are routinely used in high-rise structures and bridges as they offer high flexural rigidity. We realized that Nature is using a 2D analog of this concept in the architecture of the nucleus to safeguard the genome. Subsequently, we thought of using this geometry in man-made plate and shell materials."
"The applicability is very diverse because it's a general principle. It's not tied to any one material or particular type of structure. That means that this idea can be incorporated into a huge range of structures: aerospace structures, transport structures, defense structures, sports engineering, biomedical engineering…"
One area Agrawal is particularly interested in is the exploration of prosthetic and orthotic design.
"Those are shell structures as well," he said. "So we can now come up with lighter and stronger designs that will mitigate wear and tear experienced by the users."
The project is a collaboration with Princeton University, who will assist in the topological optimization – a mathematical method of optimizing material distribution for a given application – of the design.
"This is a whole new class of structures which has the potential to turn into its own subfield," Agrawal said. We are hoping that people will see the benefit and use it for a wide range of diverse applications."
Funding for the project runs through 2026.