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
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
The aerodynamic role of the elytra during a beetle＇s flapping motion is not well-elucidated, although it is well-recognized that the evolution of elytra has been a key in the success of coleopteran insects due to the...The aerodynamic role of the elytra during a beetle＇s flapping motion is not well-elucidated, although it is well-recognized that the evolution of elytra has been a key in the success of coleopteran insects due to their protective function. An experimental study on wing kinematics reveals that for almost concurrent flapping with the hind wings, the flapping angle of the elytra is 5 times smaller than that of the hind wings. Then, we explore the aerodynamic forces on elytra in free forward flight with and without an effect of elytron-hind wing interaction by three-dimensional numerical simulation. The numerical results show that vertical force generated by the elytra without interaction is not sufficient to support even its own weight. However, the elytron-hind wing interaction improves the vertical force on the elytra up to 80%; thus, the total vertical force could fully support its own weight. The interaction slightly increases the vertical force on the hind wind by 6% as well.展开更多
The mechanical and frictional properties of different parts of the elytra of five species of beetle were measured using a nano-indenter and a micro-tribometer. The surface microstructures of the elytra were observed b...The mechanical and frictional properties of different parts of the elytra of five species of beetle were measured using a nano-indenter and a micro-tribometer. The surface microstructures of the elytra were observed by optical microscopy and scanning white light interferometry. The surface microstructures of the elytra of all five species are characterized as non-smooth concavo-convex although specific morphological differences demonstrate the diversity of beetle elytra. Young＇s modulus and the hardness of the elytral materials vary with the species of beetle and the sampling locations, ranging from 1.80 GPa to 12.44 GPa, and from 0.24 GPa to 0.75 GPa, respectively. In general, both the Young＇s modulus and the hardness are lower in samples taken from the center of the elytra than those taken from other regions, which reflects the functional heterogeneity of biological material in the process of biological evolution. The elytra have very low friction coefficient, ranging from 0.037 to 0.079, which is related to their composition and morphology. Our measurements indicate that the surface texture and its mi- crostructural size of beetle elytra contribute to anti-friction effects.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
Beetles in the family Coccinellidae, commonly known as ladybugs, lady beetles, or ladybirds, are easily identifiable and popular beneficial insects. Current research aims to support conservation efforts of beneficial ...Beetles in the family Coccinellidae, commonly known as ladybugs, lady beetles, or ladybirds, are easily identifiable and popular beneficial insects. Current research aims to support conservation efforts of beneficial insects in agroecosystems by exploring genetic processes related to nutrition. As a part of this research, colonies of Coleomegilla maculata have been maintained in culture and inbred over many generations since 2009. One result of this inbreeding has been the discovery of novel morphological phenotypes unique to laboratory strains or present in wild populations at such low levels that they have not yet been described. One such phenotype is described here. The strain described here, ye (yellow elytra and eyes) was characterized with classical Mendelian breeding and digital image analysis. This phenotype differs from wild populations by possessing yellow pigment in the elytra and pale grey to white eyes. In contrast, wild populations of C. maculata possess pink or red pigmented elytra with black spots, and black eyes. C. maculata is not known to exhibit polymorphism in the field. Inheritance is autosomal and recessive. This species was not previously known to exhibit the dramatic variation of color described here. The strain is stable in the homozygous recessive form, and retains laboratory rearing characteristics similar to the wild type laboratory strain.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The aerodynamic role of the elytra during a beetle＇s flapping motion is not well-elucidated, although it is well-recognized that the evolution of elytra has been a key in the success of coleopteran insects due to their protective function. An experimental study on wing kinematics reveals that for almost concurrent flapping with the hind wings, the flapping angle of the elytra is 5 times smaller than that of the hind wings. Then, we explore the aerodynamic forces on elytra in free forward flight with and without an effect of elytron-hind wing interaction by three-dimensional numerical simulation. The numerical results show that vertical force generated by the elytra without interaction is not sufficient to support even its own weight. However, the elytron-hind wing interaction improves the vertical force on the elytra up to 80%; thus, the total vertical force could fully support its own weight. The interaction slightly increases the vertical force on the hind wind by 6% as well.
基金The authors acknowledge financial support from the National Nature Science Foundation of China
文摘The mechanical and frictional properties of different parts of the elytra of five species of beetle were measured using a nano-indenter and a micro-tribometer. The surface microstructures of the elytra were observed by optical microscopy and scanning white light interferometry. The surface microstructures of the elytra of all five species are characterized as non-smooth concavo-convex although specific morphological differences demonstrate the diversity of beetle elytra. Young＇s modulus and the hardness of the elytral materials vary with the species of beetle and the sampling locations, ranging from 1.80 GPa to 12.44 GPa, and from 0.24 GPa to 0.75 GPa, respectively. In general, both the Young＇s modulus and the hardness are lower in samples taken from the center of the elytra than those taken from other regions, which reflects the functional heterogeneity of biological material in the process of biological evolution. The elytra have very low friction coefficient, ranging from 0.037 to 0.079, which is related to their composition and morphology. Our measurements indicate that the surface texture and its mi- crostructural size of beetle elytra contribute to anti-friction effects.
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
文摘Beetles in the family Coccinellidae, commonly known as ladybugs, lady beetles, or ladybirds, are easily identifiable and popular beneficial insects. Current research aims to support conservation efforts of beneficial insects in agroecosystems by exploring genetic processes related to nutrition. As a part of this research, colonies of Coleomegilla maculata have been maintained in culture and inbred over many generations since 2009. One result of this inbreeding has been the discovery of novel morphological phenotypes unique to laboratory strains or present in wild populations at such low levels that they have not yet been described. One such phenotype is described here. The strain described here, ye (yellow elytra and eyes) was characterized with classical Mendelian breeding and digital image analysis. This phenotype differs from wild populations by possessing yellow pigment in the elytra and pale grey to white eyes. In contrast, wild populations of C. maculata possess pink or red pigmented elytra with black spots, and black eyes. C. maculata is not known to exhibit polymorphism in the field. Inheritance is autosomal and recessive. This species was not previously known to exhibit the dramatic variation of color described here. The strain is stable in the homozygous recessive form, and retains laboratory rearing characteristics similar to the wild type laboratory strain.
