As defined by Merriam Webster 'biomimicry' is the imitation of biological designs or processes in engineering or invention. Meaning people take what they see in nature and apply it to daily life. A brilliant example of this possibility is a unique research study covering the fields of biology, physics, and engineering simultaneously. The research was funded eight million dollars by the U.S Air force, and the study aimed to apply the beetles' adaptation into real life.
What is it?
Phloeodes Diabolicus or the Diabolical Ironclad Beetle is native to the South Western United States and can be found in woodland habitats. The beetle is about one inch in measurement. They are generally quite harmless and typically live under bark and rocks. Unlike most beetles, they don't have the ability to fly, and what also makes them unique is that their shell is callous. Ironclad beetles are so difficult to crush that entomologists know that steel pins are not enough to mount them and need to drill holes to put them on display.
Image is courtesy of CBC
Their exoskeleton is so tough because their elytra or the casings that cover their wings are fused. Researchers believe that it's a fact their shell's overall geometric design increases the strength of the beetles' armour. The patterning is reminiscent of jigsaw puzzle pieces. Compression tests were put on the beetles' elytra to see how much pressure can be put on before it got damaged. After the tests, the beetle was shown to withstand forces up to 39,000 times its own body weight. According to the study, Toughening mechanisms of the elytra of the diabolical ironclad beetle are more than twice the amount of force other species of the beetle can resist.
People involved
The main [researchers] involved in this study are David Kisailus and Pablo Zavattieri at the University of California, Irvine and Purdue University. Kisailus explains that you might expect it to break at the neck when you break a puzzle piece, which is the thinnest part. However, this does not happen to the beetle, and instead, it separates into layers rather than shattering. However, this terrestrial beetle's armour might not be lightweight but could be more like a tank. He says, "That's it's adaptation… it let's its specially designed armour take the abuse until the predator gives up". Kisailus hopes that this beetle will inspire innovation in aircraft, cars or other vehicles.
How does the jigsaw pattern work to protect the beetle?
This configuration allows weight to be more evenly distributed, thus protecting its organs. Its exoskeleton showed lateral support structures that make parts of the elytra stiffer than others because it's made from chitin, a fibrous material. Since it doesn't fly, the exoskeleton has ten percent more protein than an aerial beetle. There is further reinforcement from the seam where the elytra are fused along the insect's abdomen's length. Researchers 3-D printed samples and found sutures with fives blades where the stiffest coils take on heavier loads. Interlocking cultures allow it to resist up to 150 newtons of force. Layered microstructures that direct stress away from more vulnerable areas of the beetle, and because of this, pieces are more locked securely. Researchers believe that because of this, in the future, we may be able to have more impact-resistant structures. To further demonstrate its strength, researchers ran this beetle over with a Toyota Camry twice, only for it to survive.
Image is courtesy CBC
Future applications
An assistant professor from the University of Texas, David Restrepo, says that one engineering challenge seems to be joining different materials together without sabotaging its potential to carry loads. Right now, engineers rely on pins, bolts and adhesives to hold things together, and most techniques are prone to degrading. While using the biomimetic technique discussed for engineering, things would break more predictably instead of shattering. One application being gas turbines. Gas turbines in an aircraft are joined together with a mechanical fastener, which adds weight and could lead to more fractures in the future. These fasteners also need to be replaced often. Based on this research, UCI students built carbon fire fasteners. Purdue University found that this method made the fastener stronger than an aerospace fastener.
References
Biomimicry. (n.d.). Retrieved October 31, 2020, from https://www.merriam-
Diabolical ironclad beetle adds inspiration to structural strength. (2020, October
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Article Author: Idil Gure
Article Editors: Stephanie Sahadeo, Edie Whittington