Researchers at Indiana’s Purdue University are studying how the unusual honeycomb structures of Australian stingless bees could prove inspirational for additive manufacturing design. With their spiraled disk structure, these honeycombs demonstrate natural building concepts that could be replicated in manufacturing to create strong and efficient parts.
Of course, this wouldn’t be the first time that 3D printing had taken its cue from the work of these winged insects. In extrusion 3D printing, “honeycomb” is a preferred infill pattern for many users who value its balance of strength and aesthetic appeal. However, it’s unlikely that the behavior of real bees was studied closely to produce that common hexagonal pattern.
At Purdue University, on the other hand, the unique honeycomb building techniques of the Australian stingless bee have required close examination as researchers look to discover its secrets. The foundation of the honeycomb is a sequence of wax discs that spiral upwards like a ramp. Most interesting, however, is the use of tiny support structures between each disc layer that maintain the structural integrity of the comb.
“What is amazing about this is they actually make vertical pillars creating structural support between the discs, believe it or not,” explains Nikhilesh Chawla, Purdue’s Ransburg Professor in Materials Engineering. “The bees recycle the comb materials and use a spiral construction to efficiently build and maintain temperature stability in the comb. We can learn so much from their intelligent and multifunctional approaches to manufacturing.”
Biomimicry in AM
Chawla, an expert in four-dimensional materials science, believes the design philosophy behind these honeycomb structures could be adopted by those in the fields of structural materials and AM. Although the support structures are not completely solid, he notes, they are precisely located so the bees can maneuver in between them.
Another curious feature of the honeycomb structures of the Australian stingless bees is that they are constantly changing. When an egg hatches near the bottom of the spiral, the “cell” containing it is torn down, and building continues further up the spiral. “There is potential to learn from these reconfigurable structures they build and even the spiral, ramp-like structures,” Chawla says.
If AM engineers were to take inspiration from the behavior of these bees, it wouldn’t be the first case of “biomimicry” being used to improve 3D printed objects. A few years back, NASA awarded a $127,000 grant to advance research in bio-inspired 3D printed structures that the agency could implement in parts like heat exchangers, lightweight structures, and highly resistant skins. More recently, biomimicry has been an inspiration for some printed consumer products like light fixtures. Furthermore, although not inspired by any specific animal or plant, complex generative designs are often noted for their organic-looking forms that replicate the strength and efficiency found in nature.
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