The original inspiration for this research was actually from a peculiar insect, phylloeodes diabolicus.
In order to test the potential of this geometry as a rigid mechanical fastener to connect different materials (such as plastics and metals), a series of joints were fabricated using metal composite materials simulating the special structure of the beetles Coleoptera. Compared with the common engineering joints, the joints designed based on this special structure have greater strength and better toughness.
This research result may have great application potential and value in the fields of architecture and engineering such as aerospace.
It cant fly, so it just stays there and takes damage with specially designed armor until the predator gives up. David kisailus, one of the authors of the paper, said.
In collaboration with a team from Tokyo University of agriculture and technology, the researchers examined the chemical composition of the exoskeleton of a flying beetle and compared it with the iron beetle. The results showed that the Coleoptera was composed of chitin (chitin), fiber and protein matrix, without inorganic minerals, and its exoskeleton was much thicker than other insects. Compared with the flying beetle, the protein content of exoskeleton was significantly higher (more than 10% of body weight), and the increase of protein content was helpful to enhance the toughness of Coleoptera.
At the same time, the team also dissected the geometry that connects the two parts of the beetle, the medial suture, which looks very much like the interlocking part of a jigsaw puzzle. Rivera installed a device in an electron microscope to observe the actual performance of the connection under compression. During the compression process, the inner slit of Coleoptera was gradually stratified, but there was no fracture or breakage in the parts similar to the Puzzle.
For a long time, kisailuss laboratory has been making advanced fiber-reinforced composites based on biological characteristics. He believes that human beings are expected to find new materials for the benefit of human beings in the exoskeleton or other biological systems of the iron beetle.
This research really connects the fields of biology, physics, mechanics and materials science with engineering applications, which is not common in previous studies. Fortunately, with the support of the US air force, we have successfully established such a multidisciplinary team. Kisailus said.
To further confirm their experimental observations, the researchers used 3D printing technology to design the same structure as the iron Ding beetle. Experimental results show that the interleaved structure can provide maximum strength and durability. The outer surface of this part has a row of rods called microtricia, which act as friction pads to provide resistance against sliding.
Three different types of lateral supports enable the beetle to resist compression and deform. The intertwined structure provides maximum strength and durability for the beetles exoskeleton, while the locked and independent structures allow the beetle to deform its exoskeleton. Because of this, the beetle can squeeze into a gap in the rock or bark, just like a cockroach, which stimulates a kind of compressible robot (which can squeeze into and move in a narrow space, For searching for survivors in collapsed buildings after a disaster) or armored vehicles.
This discovery provides a new way to make solid and reliable engineering joints and they combine advanced characterization methods with mechanical testing, simulation and 3D printing to provide a template for the study of other natural materials with complex structures, said Po Yu Chen, a researcher at the University of science and technology.
However, he also believes that the research work of kisailus, Rivera and others needs to be further evaluated, such as the characteristics of the structure under compression, bending and torsion, and the change of the materials fatigue resistance over time. Moreover, their work mainly focuses on the mechanical properties of submillimeter and macro scale, but at the lower level (smaller scale) of Coleoptera The influence of structural features needs to be explored through multi-scale modeling and experiments. The use of new methods of artificial intelligence and machine learning may speed up the search of hierarchical structure materials based on the Coleoptera of iron Ding beetle.
Human beings originate from nature. Facing the uncanny craftsmanship of nature and the law of biological evolution, human beings need to maintain awe and humility. In the future, with the continuous development of science and technology and the deepening of our understanding of the world beyond human beings, we will learn from natural organisms to achieve better natural ecology.
Source: Academic headlines editor in charge: Mao Xinsi_ NBJS11624