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Tuo Z, Shi Y, Sun X, Cui J, Yang K, Liang Y, Liu C, Lin Z, Han Z, Ren L. Study of the influence of macro-structure and micro-structure on the mechanical properties of stag beetle upper jaw. Acta Biomater 2024:S1742-7061(24)00420-3. [PMID: 39097125 DOI: 10.1016/j.actbio.2024.07.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 07/12/2024] [Accepted: 07/24/2024] [Indexed: 08/05/2024]
Abstract
Macrostructural control of stress distribution and microstructural influence on crack propagation is one of the strategies for obtaining high mechanical properties in stag beetle upper jaws. The maximum bending fracture force of the stag beetle upper jaw is approximately 154, 000 times the weight of the upper jaw. Here, we explore the macro and micro-structural characteristics of two stag beetle upper jaws and reveal the resulting differences in mechanical properties and enhancement mechanisms. At the macroscopic level, the elliptic and triangular cross-sections of the upper jaw of the two species of stag beetles have significant effects on the formation of cracks. The crack generated by the upper jaws with a triangular section grows slowly and deflects easily. At the microscopic level, the upper jaw of the two species is a chitin cross-layered structure, but the difference between the two adjacent fiber layers at 45° and 50° leads to different deflection paths of the cracks on the exoskeleton. The mechanical properties of the upper jaw of the two species of stag beetle were significantly different due to the interaction of macro-structure and micro-structure. In addition, a series of bionic samples with different cross-section geometries and different fiber cross angles were designed, and mechanical tests were carried out according to the macro-structure and micro-structure characteristics of the stag beetle upper jaw. The effects of cross-section geometry and fiber cross angle on the mechanical properties of bionic samples are compared and analyzed. This study provides new ideas for designing and optimizing highly loaded components in engineering. STATEMENT OF SIGNIFICANCE: The upper jaw of the stag beetle is composed of a complex arrangement of chitin and protein fibers, providing both rigidity and flexibility. This structure is designed to withstand various mechanical stresses, including impacts and bending forces, encountered during its burrowing activities and interactions with its environment. The study of the upper jaw of the stag beetle can provide an efficient structural design for engineering components that are subjected to high loads. Understanding the relationship between structure and mechanical properties in the stag beetle upper jaw holds significant implications for biomimetic design and engineering.
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Affiliation(s)
- Zhiwei Tuo
- The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun 130025, China
| | - Yu Shi
- School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China
| | - Xianyan Sun
- Department of General Practice, The First Hospital of Jilin University, Changchun 130021, China
| | - Jiandong Cui
- The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun 130025, China
| | - Kaisheng Yang
- School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China
| | - Yunhong Liang
- The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun 130025, China; National Key Laboratory of Automotive Chassis Integration and Bionics, Jilin University, Changchun 130025, China; Institute of Structured and Architected Materials, Liaoning Academy of Materials, Shenyang 110167, China.
| | - Changyi Liu
- The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun 130025, China.
| | - Zhaohua Lin
- School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China
| | - Zhiwu Han
- The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun 130025, China; Institute of Structured and Architected Materials, Liaoning Academy of Materials, Shenyang 110167, China
| | - Luquan Ren
- The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun 130025, China; Institute of Structured and Architected Materials, Liaoning Academy of Materials, Shenyang 110167, China
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Kuwada R, Ishii D. Functionally graded structures in the involucre of Job's tears. BIOINSPIRATION & BIOMIMETICS 2024; 19:036016. [PMID: 38579734 DOI: 10.1088/1748-3190/ad3b56] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 04/05/2024] [Indexed: 04/07/2024]
Abstract
Nature is filled with materials that are both strong and light, such as bones, teeth, bamboo, seashells, arthropod exoskeletons, and nut shells. The insights gained from analyzing the changing chemical compositions and structural characteristics, as well as the mechanical properties of these materials, have been applied in developing innovative, durable, and lightweight materials like those used for impact absorption. This research concentrates on the involucres of Job's tears (Coix lacryma-jobivar.lacryma-jobi), which are rich in silica, hard, and serve to encase the seeds. The chemical composition and structural characteristics of involucres were observed using scanning electron microscopy and energy-dispersive x-ray spectroscopy and optical microscopy with safranin staining. The hardness of the outer and inner surfaces of the involucre was measured using the micro-Vickers hardness test, and the Young's modulus of the involucre's cross-section was measured using nanoindentation. Additionally, the breaking behavior of involucres was measured through compression test and three-point bending tests. The results revealed a smooth transition in chemical composition, as well as in the orientation and dimensions of the tissues from the outer to the inner layers of involucres. Furthermore, it was estimated that the spatial gradient of the Young's modulus is due to the gradient of silica deposition. By distributing the hard, brittle silica in the outer layer and elastoplastic organic components in the middle and inner layers, the involucres effectively respond to compressive and tensile stresses that occur when loads are applied to the outside of the involucre. Furthermore, the involucres are reinforced in both meridional and equatorial directions by robust fibrovascular bundles, fibrous bundles, and the inner layer's sclerenchyma fibers. From these factors, it was found that involucres exhibit high toughness against loads from outside, making it less prone to cracking.
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Affiliation(s)
- Rikima Kuwada
- Department of Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Daisuke Ishii
- Department of Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
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Matsumura Y, Gorb EV, Gorb SN. The tight attachment achieved by the male discoidal setae is possibly a counter-adaptation to the grease layer on female integument surfaces in green dock beetles. J R Soc Interface 2023; 20:20230324. [PMID: 37582406 PMCID: PMC10427193 DOI: 10.1098/rsif.2023.0324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023] Open
Abstract
Green dock beetles Gastrophysa viridula exhibit sexual dimorphism in tarsal attachment setae: females have only pointed, lanceolate and spatula-like setae, while males additionally possess discoidal ones. The sexual dimorphism is probably attributed to the necessity of male discoidal setae to adhere to the smooth back of the female during copulation. We aimed to understand its possible mechanism of attachment with G. viridula. Pull-off forces of both females and males were measured on (i) alive females, (ii) dead and dried females, and (iii) resin replicas of fresh females. The attachment ability tended to increase on dead and replicated female surfaces in both sexes, which indicates that the epicuticular grease layer on the integument of alive intact beetles decreases the attachment. This tendency was prominent in females. The present study clearly showed that in G. viridula discoidal setae enable the males to adhere stronger to female surfaces. The divergent performance found between the sexes differing in their setal composition is probably caused by the stiffness difference between the setae types and by the specific shape of the setal tips. A peculiar reproductive biology in G. viridula is probably attributed to this remarkable divergence of labour in their attachment pads between the sexes.
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Affiliation(s)
- Yoko Matsumura
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
- Department of Systematic Entomology, Graduate School of Agriculture, Hokkaido University, 060-8589 Sapporo, Japan
| | - Elena V. Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
| | - Stanislav N. Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
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Zhou J, Ng BF, Han N, Chen L, Wang Z, Li X, Zou M. Structure and mechanical properties of ladybird elytra as biological sandwich panels. J Mech Behav Biomed Mater 2023; 143:105917. [PMID: 37216753 DOI: 10.1016/j.jmbbm.2023.105917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/13/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023]
Abstract
The armour of the ladybird, elytra, protect the body from injury and are well-adapted to flight. However, experimental methods to decipher their mechanical performances had been challenging due to the small size, making it unclear how the elytra balance mass and strength. Here, we provide insights to the relationship between the microstructure and multifunctional properties of the elytra by means of structural characterization, mechanical analysis and finite element simulations. Micromorphology analysis on the elytron revealed the thickness ratio of the upper lamination, middle layer and lower lamination is approximately 51:139:7. The upper lamination had multiple cross fibre layers and the thickness of each fibre layer is not the same. In addition, the tensile strength, elastic modulus, fracture strain, bending stiffness and hardness of elytra were obtained through in-situ tensile and nanoindentation-bending under the influence of multiple loading conditions, which also serve as references for finite element models. The finite element model revealed that structural factors such as thickness of each layer, angle of fibre layer and trabeculae are key to affecting the mechanical properties, but the effect is different. When the thickness of upper, middle and lower layers is the same, the tensile strength provided by unit mass of the model is 52.78% lower than that provided by elytra. These findings broaden the relationship between the structural and mechanical properties of the ladybird elytra, and are expected to inspire the development of sandwich structures in biomedical engineering.
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Affiliation(s)
- Jianfei Zhou
- Key Lab of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130022, China; School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
| | - Bing Feng Ng
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
| | - Na Han
- Key Lab of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130022, China
| | - Lining Chen
- Key Lab of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130022, China
| | - Zhaoyang Wang
- Key Lab of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130022, China
| | - Xiujuan Li
- Key Lab of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130022, China
| | - Meng Zou
- Key Lab of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130022, China.
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Wang Z, Zhan Y, Yang Y, Wu J. Hollow mandibles: Structural adaptation to high-speed and powerful strike in the trap-jaw ant Odontomachus monticola. JOURNAL OF INSECT PHYSIOLOGY 2022; 141:104426. [PMID: 35907587 DOI: 10.1016/j.jinsphys.2022.104426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 07/18/2022] [Accepted: 07/24/2022] [Indexed: 06/15/2023]
Abstract
The trap-jaw ant Odontomachus monticola manipulates its hollow mandibles to generate extremely high speed to impact various objects through a catapult mechanism, making the violent collision occur between the mandible and the impacted objects, which increases the risk of structural failure. However, how the ant balances the trade-off between the powerful clamping and impact resistance by using this hollow structure remains elusive. In this combined experimental and theoretical investigation, we revealed that the hollowness ratio of the mandible plays an essential role in counterbalancing the trade-off. Micro-CT and high-speed images suggested that the hollow mandibles facilitate a high angular acceleration to 108 rad/s2 for an enormous clamping force. However, this hollowness might challenge the structural strength while collision occurs. We found that under the same actuating energy, the von Mises stress of the object collided by the natural mandible striking can reach up to 2.9 times that generated by the entirely solid mandible. We defined the efficiency ratio of the von Mises stress on the impacted object to that on the mandible and found the hollow mandible achieves a more robust balance between powerful clamping and impact resistance compared to the solid mandible.
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Affiliation(s)
- Zixin Wang
- School of Engineering and Technology, China University of Geosciences (Beijing), Beijing 100083, PR China
| | - Yuping Zhan
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Shenzhen 518107, PR China
| | - Yunqiang Yang
- School of Engineering and Technology, China University of Geosciences (Beijing), Beijing 100083, PR China.
| | - Jianing Wu
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Shenzhen 518107, PR China.
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Artificial and natural silk materials have high mechanical property variability regardless of sample size. Sci Rep 2022; 12:3507. [PMID: 35241705 PMCID: PMC8894418 DOI: 10.1038/s41598-022-07212-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/15/2022] [Indexed: 11/29/2022] Open
Abstract
Silk fibres attract great interest in materials science for their biological and mechanical properties. Hitherto, the mechanical properties of the silk fibres have been explored mainly by tensile tests, which provide information on their strength, Young’s modulus, strain at break and toughness modulus. Several hypotheses have been based on these data, but the intrinsic and often overlooked variability of natural and artificial silk fibres makes it challenging to identify trends and correlations. In this work, we determined the mechanical properties of Bombyx mori cocoon and degummed silk, native spider silk, and artificial spider silk, and compared them with classical commercial carbon fibres using large sample sizes (from 10 to 100 fibres, in total 200 specimens per fibre type). The results confirm a substantial variability of the mechanical properties of silk fibres compared to commercial carbon fibres, as the relative standard deviation for strength and strain at break is 10–50%. Moreover, the variability does not decrease significantly when the number of tested fibres is increased, which was surprising considering the low variability frequently reported for silk fibres in the literature. Based on this, we prove that tensile testing of 10 fibres per type is representative of a silk fibre population. Finally, we show that the ideal shape of the stress–strain curve for spider silk, characterized by a pronounced exponential stiffening regime, occurs in only 25% of all tested spider silk fibres.
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Zhang J, Yuan Q, Jiang Y, Pang H, Rajabi H, Wu Z, Wu J. Elytra coupling of the ladybird Coccinella septempunctatafunctions as an energy absorber in intentional falls. BIOINSPIRATION & BIOMIMETICS 2021; 16:056018. [PMID: 34384068 DOI: 10.1088/1748-3190/ac1cef] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 08/12/2021] [Indexed: 06/13/2023]
Abstract
Some insects, such as bees, wasps, and bugs, have specialized coupling structures to synchronize the wing motions in flight. Some others, such as ladybirds, are equipped with coupling structures that work only at rest. By locking elytra into each other, such structures provide hindwings with a protective cover to prevent contamination. Here, we show that the coupling may play another significant role: contributing to energy absorption in falls, thereby protecting the abdomen against mechanical damage. In this combined experimental, numerical and theoretical study, we investigated free falls of ladybirds (Coccinella septempunctata), and discovered that upon collision to the ground, the coupling may fail and the elytra may unlock. This unlocking of the coupling increased the energy absorption by 33%, in comparison to when the elytra remain coupled. Using micro-computed tomography scanning, we developed comparative models that enabled us to simulate impact scenarios numerically. Our results showed that unlocking of the coupling, here called elytra splitting, reduces both the peak impact force and rebound velocity. We fabricated the insect-inspired coupling mechanism using 3D printing and demonstrated its application as a damage preventing on system for quadcopters in accidental collisions.
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Affiliation(s)
- Jie Zhang
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou, 510006, People's Republic of China
| | - Qiufeng Yuan
- School of Engineering and Technology, China University of Geosciences, Beijing, 100191, People's Republic of China
| | - Yiling Jiang
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou, 510006, People's Republic of China
| | - Hong Pang
- School of Ecology, Sun Yat-Sen University, Guangzhou, 510006, People's Republic of China
| | - Hamed Rajabi
- Division of Mechanical Engineering and Design, School of Engineering, London South Bank University, London, United Kingdom
| | - Zhigang Wu
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou, 510006, People's Republic of China
| | - Jianing Wu
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou, 510006, People's Republic of China
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Ingrole A, Aguirre TG, Fuller L, Donahue SW. Bioinspired energy absorbing material designs using additive manufacturing. J Mech Behav Biomed Mater 2021; 119:104518. [PMID: 33882409 DOI: 10.1016/j.jmbbm.2021.104518] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/28/2021] [Accepted: 04/07/2021] [Indexed: 10/21/2022]
Abstract
Nature provides many biological materials and structures with exceptional energy absorption capabilities. Few, relatively simple molecular building blocks (e.g., calcium carbonate), which have unremarkable intrinsic mechanical properties individually, are used to produce biopolymer-bioceramic composites with unique hierarchical architectures, thus producing biomaterial-architectures with extraordinary mechanical properties. Several biomaterials have inspired the design and manufacture of novel material architectures to address various engineering problems requiring high energy absorption capabilities. For example, the microarchitecture of seashell nacre has inspired multi-material 3D printed architectures that outperform the energy absorption capabilities of monolithic materials. Using the hierarchical architectural features of biological materials, iterative design approaches using simulation and experimentation are advancing the field of bioinspired material design. However, bioinspired architectures are still challenging to manufacture because of the size scale and architectural hierarchical complexity. Notwithstanding, additive manufacturing technologies are advancing rapidly, continually providing researchers improved abilities to fabricate sophisticated bioinspired, hierarchical designs using multiple materials. This review describes the use of additive manufacturing for producing innovative synthetic materials specifically for energy absorption applications inspired by nacre, conch shell, shrimp shell, horns, hooves, and beetle wings. Potential applications include athletic prosthetics, protective head gear, and automobile crush zones.
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Affiliation(s)
- Aniket Ingrole
- Department of Biomedical Engineering, University of Massachusetts, Amherst, MA 01003, USA.
| | - Trevor G Aguirre
- Manufacturing Science Division, Energy Science and Technology Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Luca Fuller
- Department of Biomedical Engineering, University of Massachusetts, Amherst, MA 01003, USA
| | - Seth W Donahue
- Department of Biomedical Engineering, University of Massachusetts, Amherst, MA 01003, USA
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Lee N, Berthelson PR, Nguyen V, Garrett M, Brinda AK, Moser RD, Horstemeyer MF, Rhee H, Prabhu RK. Microstructure and nanomechanical properties of the exoskeleton of an ironclad beetle ( Zopherus haldemani). BIOINSPIRATION & BIOMIMETICS 2021; 16:036005. [PMID: 33530070 DOI: 10.1088/1748-3190/abe27b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
This study examined natural composite structures within the remarkably strong exoskeleton of the southwestern ironclad beetle (Z. haldemani). Structural and nanomechanical analyses revealed that the exoskeleton's extraordinary resistance to external forces is provided by its exceptional thickness and multi-layered structure, in which each layer performed a distinct function. In detail, the epicuticle, the outmost layer, comprised 3%-5% of the overall thickness with reduced Young's moduli of 2.2-3.2 GPa, in which polygonal-shaped walls (2-3μm in diameter) were observed on the surface. The next layer, the exocuticle, consisted of 17%-20% of the total thickness and exhibited the greatest Young's moduli (∼15 GPa) and hardness (∼800 MPa) values. As such, this layer provided the bulk of the mechanical strength for the exoskeleton. While the endocuticle spanned 70%-75% of the total thickness, it contained lower moduli (∼8-10 GPa) and hardness (∼400 MPa) values than the exocuticle. Instead, this layer may provide flexibility through its specifically organized chitin fiber layers, known as Bouligand structures. Nanoindentation testing further reiterated that the various fibrous layer orientations resulted in different elastic moduli throughout the endocuticle's cross-section. Additionally, this exoskeleton prevented delamination within the composite materials by overlapping approximately 5%-19% of each fibrous stack with neighboring layers. Finally, the innermost layer, the epidermis contributing 5%-7 % of the total thickness, contains attachment sites for muscle and soft tissue that connect the exoskeleton to the beetle. As such, it is the softest region with reduced Young's modulus of ∼2-3 GPa and hardness values of ∼290 MPa. These findings can be applied to the development of innovative, fiber-reinforced composite materials.
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Affiliation(s)
- Nayeon Lee
- Center for Advanced Vehicular Systems, Mississippi State University, Starkville, MS 39759, United States of America
| | - Parker R Berthelson
- Center for Advanced Vehicular Systems, Mississippi State University, Starkville, MS 39759, United States of America
- Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762, United States of America
| | - Vina Nguyen
- Center for Advanced Vehicular Systems, Mississippi State University, Starkville, MS 39759, United States of America
- Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762, United States of America
| | - Me'Lanae Garrett
- Center for Advanced Vehicular Systems, Mississippi State University, Starkville, MS 39759, United States of America
- Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762, United States of America
| | - AnneMarie K Brinda
- Center for Advanced Vehicular Systems, Mississippi State University, Starkville, MS 39759, United States of America
- Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762, United States of America
| | - Robert D Moser
- US Army Engineer Research and Development Center, Vicksburg, MS 39180, United States of America
| | - M F Horstemeyer
- School of Engineering, Liberty University, Lynchburg, VA 24515, United States of America
| | - Hongjoo Rhee
- Center for Advanced Vehicular Systems, Mississippi State University, Starkville, MS 39759, United States of America
- Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, United States of America
| | - R K Prabhu
- Center for Advanced Vehicular Systems, Mississippi State University, Starkville, MS 39759, United States of America
- Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762, United States of America
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Asgari M, Alderete NA, Lin Z, Benavides R, Espinosa HD. A matter of size? Material, structural and mechanical strategies for size adaptation in the elytra of Cetoniinae beetles. Acta Biomater 2021; 122:236-248. [PMID: 33359296 DOI: 10.1016/j.actbio.2020.12.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 10/22/2022]
Abstract
Nature's masterfully synthesized biological materials take on greater relevance when viewed through the perspective of evolutionary abundance. The fact that beetles (order Coleoptera) account for a quarter of all extant lifeforms on Earth, makes them prime exponents of evolutionary success. In fact, their forewings are acknowledged as key traits to their radiative-adaptive success, which makes the beetle elytra a model structure for next-generation bioinspired synthetic materials. In this work, the multiscale morphological and mechanical characteristics of a variety of beetle species from the Cetoniinae subfamily are investigated with the aim of unraveling the underlying principles behind Nature's adaptation of the elytral bauplan to differences in body weight spanning three orders of magnitude. Commensurate with the integral implications of size variation in organisms, a combined material, morphological, and mechanical characterization framework, across spatial scales, was pursued. The investigation revealed the simultaneous presence of size-invariant strategies (chemical compositions, layered-fibrous architectures, graded motifs) as well as size-dependent features (scaling of elytral layers and characteristic dimensions of building blocks), synergistically combined to achieve similar levels of biomechanical functionality (stiffness, energy absorption, strength, deformation and toughening mechanisms) in response to developmental and selection constraints. The integral approach here presented seeks to shed light on Nature's solution to the problem of size variation, which underpins the diversity of beetles and the living world.
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11
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Kundanati L, Guarino R, Pugno NM. Stag Beetle Elytra: Localized Shape Retention and Puncture/Wear Resistance. INSECTS 2019; 10:E438. [PMID: 31817427 PMCID: PMC6955947 DOI: 10.3390/insects10120438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/18/2019] [Accepted: 11/21/2019] [Indexed: 11/16/2022]
Abstract
Beetles are by far one of the most successful groups of insects, with large diversity in terms of number of species. A part of this success is attributed to their elytra, which provide various functions such as protection to their bodies from mechanical forces. In this study, stag beetle (Lucanus cervus) elytra were first examined for their overall flexural properties and were observed to have a localized shape-retaining snap-through mechanism, which may play a possible role in partly absorbing impact energy, e.g., during battles and falls from heights. The snap-through mechanism was validated using theoretical calculations and also finite element simulations. Elytra were also characterized to examine their puncture and wear resistance. Our results show that elytra have a puncture resistance that is much higher than that of mandible bites. The measured values of modulus and hardness of elytra exocuticle were 10.3 ± 0.8 GPa and 0.7 ± 0.1 GPa, respectively. Using the hardness-to-modulus ratio as an indicator of wear resistance, the estimated value was observed to be in the range of wear-resistant biological material such as blood worms (Glyrcera dibranchiata). Thus, our study demonstrates different mechanical properties of the stag beetle elytra, which can be explored to design shape-retaining bio-inspired composites with enhanced puncture and wear resistance.
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Affiliation(s)
- Lakshminath Kundanati
- Laboratory of Bio- Inspired & Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano, 77, 38123 Trento, Italy; (L.K.); (R.G.)
| | - Roberto Guarino
- Laboratory of Bio- Inspired & Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano, 77, 38123 Trento, Italy; (L.K.); (R.G.)
| | - Nicola M. Pugno
- Laboratory of Bio- Inspired & Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano, 77, 38123 Trento, Italy; (L.K.); (R.G.)
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK
- Ket Lab, Edoardo Amaldi Foundation, Via del Politecnico snc, 00133 Rome, Italy
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12
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Sykes D, Hartwell R, Bradley RS, Burnett TL, Hornberger B, Garwood RJ, Withers PJ. Time-lapse three-dimensional imaging of crack propagation in beetle cuticle. Acta Biomater 2019; 86:109-116. [PMID: 30660007 DOI: 10.1016/j.actbio.2019.01.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/09/2019] [Accepted: 01/14/2019] [Indexed: 11/17/2022]
Abstract
Arthropod cuticle has extraordinary properties. It is very stiff and tough whilst being lightweight, yet it is made of rather ordinary constituents. This desirable combination of properties results from a hierarchical structure, but we currently have a poor understanding of how this impedes damage propagation. Here we use non-destructive, time-lapse in situ tensile testing within an X-ray nanotomography (nCT) system to visualise crack progression through dry beetle elytron (wing case) cuticle in 3D. We find that its hierarchical pseudo-orthogonal laminated microstructure exploits many extrinsic toughening mechanisms, including crack deflection, fibre and laminate pull-out and crack bridging. We highlight lessons to be learned in the design of engineering structures from the toughening methods employed. STATEMENT OF SIGNIFICANCE: We present the first comprehensive study of the damage and toughening mechanisms within arthropod cuticle in a 3D time-lapse manner, using X-ray nanotomography during crack growth. This technique allows lamina to be isolated despite being convex, which limits 2D analysis of microstructure. We report toughening mechanisms previously unobserved in unmineralised cuticle such as crack deflection, fibre and laminate pull-out and crack bridging; and provide insights into the effects of hierarchical microstructure on crack propagation. Ultimately the benefits of the hierarchical microstructure found here can not only be used to improve biomimetic design, but also helps us to understand the remarkable success of arthropods on Earth.
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Affiliation(s)
- Dan Sykes
- Henry Moseley X-ray Imaging Facility, The Royce Institute, School of Materials, The University of Manchester, Manchester M13 9PL, UK.
| | - Rebecca Hartwell
- Henry Moseley X-ray Imaging Facility, The Royce Institute, School of Materials, The University of Manchester, Manchester M13 9PL, UK
| | - Rob S Bradley
- Henry Moseley X-ray Imaging Facility, The Royce Institute, School of Materials, The University of Manchester, Manchester M13 9PL, UK
| | - Timothy L Burnett
- Henry Moseley X-ray Imaging Facility, The Royce Institute, School of Materials, The University of Manchester, Manchester M13 9PL, UK
| | | | - Russell J Garwood
- School of Earth and Environmental Science, The University of Manchester, Manchester M13 9PL, UK; Earth Sciences Department, Natural History Museum, London SW7 5BD, UK
| | - Philip J Withers
- Henry Moseley X-ray Imaging Facility, The Royce Institute, School of Materials, The University of Manchester, Manchester M13 9PL, UK
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