Honeycombs are a hallmark of nature-inspired design, showcasing an effective construction method crafted by nature’s sweet (and buzzing) six-legged engineers.
Overlaying the honeycomb structure onto any design instantly enhances its strength, sustainability, and visual appeal.
In this article, we explore two key topics: why the hexagon is such a brilliant structural shape and a new discovery that makes it even more compelling and practical.
Why Hexagons Are Brilliant:
Hexagons excel in construction for two main reasons:
- Maximized Volume with Minimal Material: They create a larger internal space using less material.
- High Resistance to Buckling: They perform exceptionally well under compressive forces. This combination of efficiency makes them favorites among aerospace engineers and packaging designers.
The Surprising Wonders of Hexagons:
After over 2,000 years of study, there’s still more to uncover about honeycombs.
What Can We Still Learn from Honeycombs?
Honeycombs have inspired numerous innovations, ranging from cooling materials to impact-resistant aircraft designs and architectural stability solutions.
A research team funded by NASA made a remarkable discovery about honeycomb structures: while industrially designed honeycombs feature sharp corners, studies of social insect nests (particularly bees and wasps) revealed that natural structures rarely have such angles—they tend to be more rounded. Some might even describe these shapes as “organic.”
Notice the sharp angles in industrial honeycomb structures versus the softer, more organic corners of those made by bees. This observation raises an intriguing question: what structural advantages might these rounded corners provide? What is the optimal corner radius for human-designed honeycombs, and in what contexts should it be applied?
Three Key Insights on Rounded Corners:
- Enhanced Structural Efficiency: Rounded corners improve geometric stiffness, meaning that if maximizing stiffness were the sole design goal, the ideal shape would be circular.
- Optimal Corner Radius: Each honeycomb cell has an ideal corner radius, which increases with wall thickness.
- Reduced Risk of Cracking: The presence of a corner radius diminishes stress concentrations at junctions, making this design attractive for energy absorption applications, such as in aerospace and automotive contexts.
Bees have evolved a more rounded internal cell shape, optimizing strength while sacrificing lightness. Why? Hives must be robust enough to support significant weights of honey and larvae over time without deforming. In contrast, paper wasps and hornets use nearly perfect hexagonal cells, creating lightweight yet more fragile nests suitable for their short-lived uses.
The Discovery Journey
To understand this finding, we must take a step back in history.
In 36 BCE, Roman beekeeper and scholar Marcus Terentius Varro hypothesized that honeycombs used hexagonal cells to conserve wax while storing more honey. Bees work smart, not just hard—a concept known as the “Honeycomb Hypothesis.”
Mathematician Thomas Hales later clarified this hypothesis, providing a mathematical proof in 1999 that validated Varro’s theory.
Why Is the Honeycomb Structure Ideal for Aviation?
The honeycomb structure boasts a high strength-to-weight ratio—making it both strong and lightweight, capable of withstanding significant forces while using minimal material.
The aerospace and space industries particularly value this nature-inspired design. Honeycomb core sandwich panels are featured in various airplane components, from fuselages and wings to ailerons and flaps. Remarkably, honeycombs are even used in the design of onboard toilets!
A New Discovery
Despite two millennia of study, researchers continue to find new insights into honeycombs.
Dr. Clint Penick, an assistant professor at Kennesaw State University and an entomologist passionate about social insects, teamed up with Dhruv Bhate, an engineer specializing in 3D printing and industrial honeycomb structures. Their collaboration at the Biomimicry Center at Arizona State University led to an unexpected finding: industrial honeycombs are made of ideal hexagons with sharp corners, while those created by bees tend to have rounded corners.
With NASA’s support, they researched functional applications of this discovery, focusing on the best honeycomb shapes for design purposes. They tested over 70 species of bees and wasps, examining cell size, wall thickness, and corner roundness.
They found that larger corner radii enhance stiffness and reduce material use, but also recognized that hives must withstand mechanical stress. Their significant finding: rounded corners in thicker walls reduce stress and strengthen the honeycomb, while in thinner walls, they create additional stress and weaken the structure. Thus, the ideal corner roundness can be determined by the cell size-to-wall thickness ratio.
This serendipitous collaboration between a biologist and an engineer underscores the value of interdisciplinary work.
The Need for More Than Just Biologists in Biomimicry
Biologists are rarely invited to the design table, which is a mistake. They can interpret nature like a text and apply that knowledge to create sustainable designs.
Biomimicry has become synonymous with nature-inspired innovation, which thrives on the fusion of diverse perspectives. It requires collaboration among engineers, computer scientists, mathematicians, physicists, biologists, beekeepers, and even textile designers and artists.
When we blend these viewpoints, fresh insights emerge—sparking new discoveries. This case exemplifies how the meeting of a biologist and an engineer led to groundbreaking research.
Summary
- Why Hexagons Are Great: They provide more volume with less material and exhibit high resistance to buckling.
- What Makes Hexagons Even More Amazing: The internal arrangement of material can be adjusted to optimize strength or lightness; a more rounded internal shape results in a stronger (albeit heavier) structure.
There remains much innovation to discover in plain sight.
Nature-inspired innovation is about achieving “more with less”—more food from less land and water, more miles per gallon of fuel, more communication with less energy consumption, and sturdy buildings made with less steel.
The beauty of the honeycomb structure is woven into our design world—a subtle yet powerful reminder that nature knows best.
Let’s not forget this!
References:
- Learning from Nature: The Biomimicry Podcast with Lily Urmann
- How Does Nature Optimize Space and Manage Compression? With Dr. Clint Penick
- Parametric Optimization of Corner Radius in Hexagonal Honeycombs under In-plane Compression
