We conducted a comprehensive study to investigate the aerodynamic characteristics and force generation of the elytra of abeetle,Allomyrina dichotoma.Our analysis included wind tunnel experiments and three-dimensional ...We conducted a comprehensive study to investigate the aerodynamic characteristics and force generation of the elytra of abeetle,Allomyrina dichotoma.Our analysis included wind tunnel experiments and three-dimensional computational fluiddynamics simulations using ANSYS-CFX software.Our first approach was a quasi-static study that considered the effect ofinduced flapping flow due to the flapping motion of the fore-wings (elytra) at a frequency of around 30 Hz to 40 Hz.The dihedralangle was varied to represent flapping motion during the upstroke and downstroke.We found that an elytron producespositive lift at 0° geometric angle of attack,negative lift during the upstroke,and always produces drag during both the upstrokeand downstroke.We also found that the lift coefficient of an elytron does not drop even at a very high geometric angle of attack.For a beetle with a body weight of 5 g,based on the quasi-static method,the fore-wings (elytra) can produce lift of less than 1%of its body weight.展开更多
Ladybirds(Coccinella septempunctata)are adept at living in humid conditions as their elytra can effectively shield their bodies from raindrops.However,due to technical difficulties in examining the delicate structure,...Ladybirds(Coccinella septempunctata)are adept at living in humid conditions as their elytra can effectively shield their bodies from raindrops.However,due to technical difficulties in examining the delicate structure,the understanding of the water-proofing mechanism of the coupling structure and its impact on the dome-like elytra response to the raindrops remain elusive.In this combined experimental and theoretical study,we showed that the coupling structure on the ladybird elytra can ward off the raindrops traveling at a velocity of 6 m/s,which generates an impact force equivalent to 600 times the body weight.The waterproofing mechanism relies on the deformability of the elytra and their microstructures,which collectively impedes the formation of microchannels for liquids.The enhanced water-proofing capabilities enabled by the coupling structures are validated through experimental testing on comparative 3D-printed models,showing the effectiveness of these structures in improving water resistance.Subsequently,we showcased a water-proofing device,which substantially improved the efficiency of solar panels in converting solar energy.This multidisciplinary study not only advances our understanding of the biomechanics of coupling systems in insects but also inspires the design of water-proofing deployable structures.展开更多
Lightweight materials, structures and coupling mechanisms are very important for realizing advanced flight vehicles. Here, we obtained the geometric structures and morphologies of the elytra of beetles and ascertained...Lightweight materials, structures and coupling mechanisms are very important for realizing advanced flight vehicles. Here, we obtained the geometric structures and morphologies of the elytra of beetles and ascertained its coupling zone by using the histological section technique and SEM. We set up a three-dimensional motion observing system to monitor the opening and closing behaviour of elytra in beetles and to determine the motion mechanism. We constructed a force measuring system to measure the coupling forces between elytra. The results show that elytra open and close by rotating about a single axle, where the coupling forces may be as high as 160 times its own bodyweight, the elytra coupling with the tenon and mortise mechanism, surface texture and opening angle between elytra heavily influence the coupling forces. These results may provide insights into the design mechanism and structure for future vehicles of flight.展开更多
To clarify the dynamic construction of Allomyrina dichotoma (Linné) elytra, the distribution of trabeculae and surface structures has been investigated using scanning electron microscopy and transmitted light...To clarify the dynamic construction of Allomyrina dichotoma (Linné) elytra, the distribution of trabeculae and surface structures has been investigated using scanning electron microscopy and transmitted light. There are solid trabeculae in the elytron and under penetrating light these can be seen as black dots. It is clear that trabeculae arrangement is almost entirely irregular throughout the elytron, except for some approximately straight alignment near some trachea. This irregular arrangement is different from the longitudinal rows of striations that are well known in other species, and there are no hollowed striae (punctures) on the elytral surface of A. dichotoma. Throughout the internal architecture of the elytron, there are mesh like (honeycomb) structures. Each honeycomb usually has 1-2 trabeculae mainly distributed at the corners of the honeycomb. The number of trabeculae present on each honeycomb is dependent on the size of the honeycomb.展开更多
The mechanical properties and the topological structure of cross-sections found in Cybister elytra are presented.SEM images show the similar geometric structure in transverse and longitudinal sections.Elytra consist o...The mechanical properties and the topological structure of cross-sections found in Cybister elytra are presented.SEM images show the similar geometric structure in transverse and longitudinal sections.Elytra consist of several layers:a dense,black epicuticle,an exocuticle that is braided by several parallel chitin fiber layers in a helix structure,and many bridge piers formed by the fiber bundles that connect the exocuticle to the endodermis,forming a composite,light-weight biomaterial.The mechanical properties along the edge of elytra are measured using a nano-indenter.The hardness and modulus of fresh cybister elytra is 0.31 GPa and 6.13 GPa,respectively.The ultimate stresses of fresh elytra,measured by using a tensile test machine,are 169.2 MPa and 194.5 MPa in the transverse and longitudinal directions,respectively,which is twice higher than that of the dried one.The difference in the two directions indicates that this bio-material has been topologically optimized during evolution.The results may provide a biological template to inspire lightweight structure design for aerospace engineering.展开更多
On the basis of the microstructure of the cross-section of a beetle's elytra,three bio-inspired lightweight structures were designed and built from acrylonitrile butadiene styrene plastic with a three-dimensional ...On the basis of the microstructure of the cross-section of a beetle's elytra,three bio-inspired lightweight structures were designed and built from acrylonitrile butadiene styrene plastic with a three-dimensional printer.The mechanical properties of three lightweight structures were analyzed and compared employing the finite element method,and quasi-static compression experiments and a three-point bending test on the structure samples were carried out using an electronic universal testing machine to verify the effectiveness of the finite element method.The results show that all three bio-structures were lightweight and had excellent mechanical properties.In particular,the bio-structure with spherical holes and hollow columns perpendicular to the top and bottom surfaces best imitated the microstructure of the cross-section of the Cybister elytra and had the greatest specific strength/stiffness in compression and bending.Finally,a preliminary optimization design was obtained for this bio-structure to further improve its specific strength and specific stiffness to 31.82 kN m/kg and 108.73 kN m 2 /kg respectively.展开更多
基金supported by the Basic Science Research Program of the National Research Foundation of Korea (NRF)funded by the Ministry of Education,Science and Technology of the Korean government (Grant No.2010-0018884)
文摘We conducted a comprehensive study to investigate the aerodynamic characteristics and force generation of the elytra of abeetle,Allomyrina dichotoma.Our analysis included wind tunnel experiments and three-dimensional computational fluiddynamics simulations using ANSYS-CFX software.Our first approach was a quasi-static study that considered the effect ofinduced flapping flow due to the flapping motion of the fore-wings (elytra) at a frequency of around 30 Hz to 40 Hz.The dihedralangle was varied to represent flapping motion during the upstroke and downstroke.We found that an elytron producespositive lift at 0° geometric angle of attack,negative lift during the upstroke,and always produces drag during both the upstrokeand downstroke.We also found that the lift coefficient of an elytron does not drop even at a very high geometric angle of attack.For a beetle with a body weight of 5 g,based on the quasi-static method,the fore-wings (elytra) can produce lift of less than 1%of its body weight.
基金Shenzhen Science and Technology Program,Grant/Award Numbers:GXWD2021B03,20220817165030002National Natural Science Foundation of China,Grant/Award Numbers:T2422031,52275298Postdoctoral Fellowship Program of CPSF,Grant/Award Number:GZC20240192。
文摘Ladybirds(Coccinella septempunctata)are adept at living in humid conditions as their elytra can effectively shield their bodies from raindrops.However,due to technical difficulties in examining the delicate structure,the understanding of the water-proofing mechanism of the coupling structure and its impact on the dome-like elytra response to the raindrops remain elusive.In this combined experimental and theoretical study,we showed that the coupling structure on the ladybird elytra can ward off the raindrops traveling at a velocity of 6 m/s,which generates an impact force equivalent to 600 times the body weight.The waterproofing mechanism relies on the deformability of the elytra and their microstructures,which collectively impedes the formation of microchannels for liquids.The enhanced water-proofing capabilities enabled by the coupling structures are validated through experimental testing on comparative 3D-printed models,showing the effectiveness of these structures in improving water resistance.Subsequently,we showcased a water-proofing device,which substantially improved the efficiency of solar panels in converting solar energy.This multidisciplinary study not only advances our understanding of the biomechanics of coupling systems in insects but also inspires the design of water-proofing deployable structures.
基金State"973"Programs from the Ministry of Science and Technology of China (GrantNo.2007CB607600)National Natural Science Foundation of China (GrantNos.60535020 and 50635030)
文摘Lightweight materials, structures and coupling mechanisms are very important for realizing advanced flight vehicles. Here, we obtained the geometric structures and morphologies of the elytra of beetles and ascertained its coupling zone by using the histological section technique and SEM. We set up a three-dimensional motion observing system to monitor the opening and closing behaviour of elytra in beetles and to determine the motion mechanism. We constructed a force measuring system to measure the coupling forces between elytra. The results show that elytra open and close by rotating about a single axle, where the coupling forces may be as high as 160 times its own bodyweight, the elytra coupling with the tenon and mortise mechanism, surface texture and opening angle between elytra heavily influence the coupling forces. These results may provide insights into the design mechanism and structure for future vehicles of flight.
文摘To clarify the dynamic construction of Allomyrina dichotoma (Linné) elytra, the distribution of trabeculae and surface structures has been investigated using scanning electron microscopy and transmitted light. There are solid trabeculae in the elytron and under penetrating light these can be seen as black dots. It is clear that trabeculae arrangement is almost entirely irregular throughout the elytron, except for some approximately straight alignment near some trachea. This irregular arrangement is different from the longitudinal rows of striations that are well known in other species, and there are no hollowed striae (punctures) on the elytral surface of A. dichotoma. Throughout the internal architecture of the elytron, there are mesh like (honeycomb) structures. Each honeycomb usually has 1-2 trabeculae mainly distributed at the corners of the honeycomb. The number of trabeculae present on each honeycomb is dependent on the size of the honeycomb.
基金supported by the National Natural Science Foundation of China (Grant Nos.key project:50635030 and general project:50675160)Aviation Science Foundation of China (Grant No.2007ZA52008)
文摘The mechanical properties and the topological structure of cross-sections found in Cybister elytra are presented.SEM images show the similar geometric structure in transverse and longitudinal sections.Elytra consist of several layers:a dense,black epicuticle,an exocuticle that is braided by several parallel chitin fiber layers in a helix structure,and many bridge piers formed by the fiber bundles that connect the exocuticle to the endodermis,forming a composite,light-weight biomaterial.The mechanical properties along the edge of elytra are measured using a nano-indenter.The hardness and modulus of fresh cybister elytra is 0.31 GPa and 6.13 GPa,respectively.The ultimate stresses of fresh elytra,measured by using a tensile test machine,are 169.2 MPa and 194.5 MPa in the transverse and longitudinal directions,respectively,which is twice higher than that of the dried one.The difference in the two directions indicates that this bio-material has been topologically optimized during evolution.The results may provide a biological template to inspire lightweight structure design for aerospace engineering.
基金supported by the National Basic Research Program of China (2011CB302106)the National Natural Science Foundation of China (51175249,30770285)+1 种基金the Major Research Plan of the National Natural Science Foundation of China (90916021)the Jiangsu Natural Science Foundation (BK2009376)
文摘On the basis of the microstructure of the cross-section of a beetle's elytra,three bio-inspired lightweight structures were designed and built from acrylonitrile butadiene styrene plastic with a three-dimensional printer.The mechanical properties of three lightweight structures were analyzed and compared employing the finite element method,and quasi-static compression experiments and a three-point bending test on the structure samples were carried out using an electronic universal testing machine to verify the effectiveness of the finite element method.The results show that all three bio-structures were lightweight and had excellent mechanical properties.In particular,the bio-structure with spherical holes and hollow columns perpendicular to the top and bottom surfaces best imitated the microstructure of the cross-section of the Cybister elytra and had the greatest specific strength/stiffness in compression and bending.Finally,a preliminary optimization design was obtained for this bio-structure to further improve its specific strength and specific stiffness to 31.82 kN m/kg and 108.73 kN m 2 /kg respectively.
基金National Science Fund for Distinguished Young Scholars of China (Grant No. 50025516)"985 Project" of Jilin University, Natural Science Foundation of Henan Educational Committee (Grant No. 2009B210006)+1 种基金Science Foundation (2008QN004)Scientific Research Foundation for Ph. Doctor, Henan University of Science and Technology
