Amazingly stable, durable, and shatter-resistant: Researchers report that what lies behind the astonishing features of insect wings can be transferred to the technology. It demonstrates how the combination of flexible joints, mechanical seals and “twisting zones” make insect wings effective and shock resistant. By recreating these elements that they transferred to 3D printed aircraft models, they were able to illustrate the efficiency of the concept. The researchers say that the system consisting of three components could open new possibilities in the development of technical systems.
Dragonflies, bees, and the like take to the air with an amazingly powerful “lightweight building technique”: their wings usually only make up 2% of the total mass of insects, yet rock structures are difficult to withstand: in addition to the large size air loads, they can also withstand heavy loads and bump stops . It escapes frequent collisions with obstacles such as flowers, leaves, or twigs without major damage. Until now, human technology has not been able to guarantee these performance combinations with regard to high endurance. But how can they get an insect’s wings out? The working group “Functional morphology and biomechanics” at Christian-Albrechts-Universität zu Kiel deals with this question. The focus is on the relatively large wings of a dragonfly.
As the scientists explain, technical constructions can usually effectively guarantee only one property: either they can withstand large loads, such as stable structural components in buildings, or their flexibility makes them particularly shatterproof in the event of collisions. If both features can be better combined, more efficient technical structures can be developed that can adapt their adaptability to related requirements. However, the methods prior to this are often complex and expensive, and thus are hardly suitable for widespread use, say the scientists.
“What is still a concern of engineering research is something that insects have mastered long ago,” says co-author Stanislav Gurp. In the current study, he and colleagues demonstrated the peculiarities in the structure of insects’ wings upon which the set of interesting characteristics is based. They also report that three elements in the wing structure and structure form the basis for this: flexible joints, mechanical seals and “torsion zones”. “Thanks to this special structure, insect wings can adopt different degrees of flexibility, depending on what the specific condition requires,” says Sock.
As the researchers explain, insect wings consist of veins with a membrane stretched between them. Micro connections connect individual wires and enable wings to bend under reduced load. These elements also ensure that the structure can withstand long-term loads, the researchers explain. However, with increased pressure, movement is stopped by microscopic ripples located on the delicate joints. The researchers explained that these “plugs” support the wings against heavy loads. The number three of the structural elements then form special zones in the wing used in collisions
Play with Obstacles: Due to their high deformability, they allow non-destructive and reversible twisting, preventing structures from breaking. “Thanks to these three elements, insects are able to adapt the properties of their wings and thus perform multiple functions at the same time,” explains first author Ali Khashishi.
Concept transfer to model aircraft
As part of their study, the researchers artificially simulated these biomechanical elements and were able to demonstrate their technical efficiency and potential. They moved the items to about eight centimeters in size and 3.8 grams in weight aircraft models, which they produced using 3D printing. This process allowed the wings to be fitted with functional replicas of the delicate joints, stoppers, and sprained areas of insects’ wings (see illustration). The researchers then subjected these models and controls without the elements to different stress experiments. They also allowed the models to hit obstacles and on the ground.
Wings with bio-inspired elements have been shown to survive collisions, while conventional aircraft models have been shattered. In addition, the scientists tested several modified constructions in which they omitted one of the three building blocks. “These experiences confirm that all three elements are necessary together to ensure a combination of features,” says Khashishi.
As the scientists point out, the convertibility of a biological concept into a technical one now demonstrates the potential for developing applications. A particularly interesting aspect of the biologically inspired system is that the strategy is based on structural elements in the wings that operate independently – without additional energy required. “Such findings from biology could help us build technical systems that adapt independently to extreme or unexpected situations – for example in environments where humans cannot actively intervene, such as spaceflight,” co-author Hamid Rajabi says in closing.
Source: Christian-Albrechts-Universität zu Kiel, specialist article: Case. Science, doi: 10.1002 / advs.202004338