- Written by Benjamin Wright -
Nature doesn’t waste energy, and nature finds ways to adapt to a changing world. Understanding those two principles led David Frost to his interest in bio-inspired design. Frost, the Elizabeth and Bill Higginbotham Professor in Georgia Tech’s School of Civil and Environmental Engineering, has spent the last dozen years searching for ways to use nature’s efficiency and ingenuity to improve the civil engineering field. His efforts are paying off. In the last year alone, research from his lab has resulted in multiple patent filings, licensing agreements, and product launches — all of which take their inspiration from the biological world.
Many of those research projects have been the subjects of doctoral research by Frost’s students, with support and advisement from Michael Helms, co-director of Georgia Tech’s Center for Biologically Inspired Design (CBID) and the Brook Byers Institute for Sustainable Systems lead for biologically inspired design. The CBID mandate is to encourage researchers to find inspiration in the biological world, where design solutions have been in development for three-and-a-half billion years as life has on Earth has evolved. Building on the concept that nature isn’t wasteful, one of the goals of bio-inspired design is to develop products that are both energy and materially efficient, and therefore more sustainable.
As the subsurface exploration and excavation thrust leader for the National Science Foundation (NSF) Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), Frost focuses on what’s going on below the planet’s surface. His inspiration comes from things like tree roots, earthworms, spider webs, and ant colonies. In fact, ants are what first got him interested in bio-inspired design.
“There are many organism systems that have not been thought of as necessarily the most intelligent systems. But in fact, they are following a set of rules, approaches, or guidelines and are producing things that, in the end, are both energy- and resource-efficient and adaptive,” said Frost. “One of these is ant colonies. We see the hills above ground, but what’s going on below the ground, with the tunnels and chambers, is fascinating.”
Early in his time with CBBG, Frost came across a Florida artist who made metal castings of ant colony structures. Frost acquired some, made more castings of his own, and then built digital models of ant colonies to understand how the structures maintain their strength. He also studied exactly how ants build such complex structures so efficiently.
“They take advantage of capillarity, arching effects, and the strength of spirals,” explained Frost.
Ants dig by carefully and quickly probing each grain of sand or dirt, in the same way a human might test a Jenga piece, before deciding whether it can be safely removed without damaging the tunnel. As a result, ants are extremely energy efficient as they dig, continually removing the least encumbered pieces of material. Based on this information, Frost and his team are exploring ways to improve the effectiveness and energy usage of tunnel-boring machines.
Other bio-inspired projects from Frost’s research that are further along in the development process include building anchors inspired by tree roots, a ground heat-exchange system based on spirals and plant xylem, a geogrid (or stabilization mesh) design based on spiderwebs, a worm-inspired soil probe, and another probe design influenced by a vortex and centipedes that would displace a minimum amount of soil.
“I'm convinced that just about any system in nature we look at will help us think about analogs for things that, as human engineers, we’d like to do — and do better,” said Frost. “The opportunities for inspiration and improvement are endless.”
Take the Root-Inspired Ground Anchor (RIGA), for example. Anchors are an essential element in construction, stabilizing retaining walls and other foundation structures. Traditionally, anchors are straight poles inserted into the ground. Looking at tree roots, Frost wondered if there was a better way. That thought led him to inventing an anchor that can be driven into the ground and then expanded under the surface, similar to the structure of tree roots. The expandable anchor improves load capacity by up to 75% and is about two-thirds as long as a conventional anchor. After years of refinement, the device has been patented, licensed, and is the basis of a startup founded by Ph.D. student John Huntoon.
Frost takes the most pride in the real-world impact of his bio-inspired designs. Since 2023, Georgia Tech has filed, or is in the process of filing, utility patents for five of them. Like the RIGA system, those patents will be available for licensing for commercial use. Companies have already contacted Frost about his heat-exchange and geogrid concepts.
“Civil engineering doesn’t traditionally have a culture of patent-producing research,” noted Frost. “It’s exciting to see these filings and how they can generate energy and enthusiasm for studying natural systems and using what we learn to improve the world. Practical application has always been very important to me.”
Frost is finding that practical application also appeals to the next generation of civil engineers — specifically K-12 students interested in the profession who tour the CBID affiliated labs on campus. The students study nature’s designs and figure out how to apply them, rather than learn traditional construction methods.
“Ants, spiders, and worms are immediately relatable for middle- and high-school students,” Frost said. “They think engineering is all math and science, and that doesn’t sound fun to them. Instead, we show them they can be inspired by anything and then use that to make it about conservation and adaptation and energy minimization. Those are things they are interested in.”
Frost is hopeful that the students of today and tomorrow will continue to take inspiration from nature, enabling humans to adapt to a changing world as effectively as nature has.
