WCX 2023: Biomimicry Inspires Product Development

Nature’s own design nuances may hold the key to novel product features.

April 19, 2023

Kami Buchholz

One of NASA’s bio-inspired broadband acoustic absorber prototypes is shown in the NASA Glenn Research Center’s DGEN Aeropropulsion Research Turbofan (DART) engine inlet. NASA is developing the technology for potential use as acoustic liners inside of aircraft engines. (NASA GRC)

Nature has always served as a giant classroom where problem-solving lessons are taught — a “storehouse of inspiration for new and different ideas,” noted Trisha Brown, co-director of Great Lakes Biomimicry, based in Cleveland, Ohio. Biomimicry is the design and production of materials, structures, and systems that are modeled on biological entities and processes.

The tiny bumps on the pads of polar bear paws may hold the key to greater grip for vehicle tires, shoes or gloves. (University of Akron)

SAE Media spoke with Brown and others involved in the biomimicry field ahead of SAE’s WCX 2023 event, where a wide discussion on the topic took place. The natural library is under study by research teams at NASA as the space agency searches for ways to make air transportation cleaner, safer and quieter. “We are working on futuristic flight vehicles of every size, shape, and speed, and we are turning to nature for inspiration,” noted L. Danielle Koch, aerospace engineer with the NASA Glenn Research Center Acoustics Branch in Cleveland.

Koch recounted that while on vacation in Oregon’s wilderness, she intently listened to the wind rushing over thousands of acres of trees — all without any background noise from transportation vehicles. No blaring horns, revving engines or squealing brakes. That experience intensified a quest to learn more about the acoustic absorption characteristics of natural materials. She collaborated with others on the same topic, all of which eventually led to the realization of NASA’s patented Bio-inspired Broadband Acoustic Absorber.

“This is a new structure that resembles bundles of natural reeds that can absorb unwanted sound between 400 Hertz and 3000 Hertz,” Koch explained. The structure absorbs low-frequency sound below 1000 Hz significantly better than current materials of similar thicknesses and weights, she noted.

Absorbing low-frequency sound is difficult to accomplish via thin and lightweight absorbers. It’s even more troublesome if the acoustic absorber is installed in a harsh environment that involves exposure to high temperatures or sprays of solid or liquid debris. “We believe this is a promising new structure that could have broad commercial use, especially in the age of additive manufacturing,” Koch said. Research at NASA suggests that this technology can be developed into a multi-functional structure that absorbs sound and possibly can transfer heat and/or carry a load, which could help enable more electric transportation.

A magnified view of the bumps on a polar bear’s paw pad. (University of Akron)

Polar bears possess an innate ability to traverse ice without slipping and sliding. Learning more detail about such unique animal capabilities became an investigative mission for a research group spearheaded by Dr. Ali Dhinojwala, professor of polymer sciences at the School of Polymer Science and Polymer Engineering at The University of Akron in Ohio. The bumps on the pads of polar bear paws were of great interest to the team.

“We initially thought that the tiny bumps were responsible for the [bears’] grip. But after doing a comparative study of bears [brown, sun and polar bears], we discovered that the bumps aren’t the distinguishing feature,” said Dhinojwala. Those bottom-of-paw pads that help the polar bears adhere to low-mu surfaces are bigger (approximately 0.039-in/1 mm in diameter and 0.0078-in/0.2 mm in height) than the paw bumps of other bear species. To further study how the bumps help with traction, the team created 3D-printed polymer structures that mimic, rather than fully replicate, the bear’s paw-pad surface.

Taking that knowledge and translating it into a physical structure is the team’s next step. The preferred outcome would lead to a patented production application for vehicle tires, gloves, or shoes. “We are working on several ideas that have the potential to become automotive applications,” Dhinojwala said.

Image shows a synthetic 3D-printed structure that a research team at the University of Akron tested on snow. (University of Akron)

Product developers know that not every idea becomes production reality. But generating ideas is the start point. “Think about nature as an experimental system that has evolved over billions of years,” Dhinojwala noted. “Nature’s optimization is very inspirational.”

Nature’s strength also is its sustainability, an increasingly vital business tenet which biomimicry can help achieve. “There isn’t a waste of materials and energy. Things are done as efficiently as possible in nature,” Brown added. For industry suppliers, being proactive about planning and implementing a sustainability roadmap can be vital to business survival.

“Every company needs a plan. If you want to be around for another 10-15 years, you better have a sustainability strategy,” Brown said.