Beetle Forewing Research Articles

Designing Lightweight 3D-Printable Bioinspired Structures for Enhanced Compression and Energy Absorption Properties.

Recent progress in additive manufacturing, also known as 3D printing, has offered several benefits, including high geometrical freedom and the ability to create bioinspired structures with intricate details. Mantis shrimp can scrape the shells of prey molluscs with its hammer-shaped stick, while beetles have highly adapted forewings that are lightweight, tough, and strong. This paper introduces a design approach for bioinspired lattice structures by mimicking the internal microstructures of a beetle's forewing, a mantis shrimp's shell, and a mantis shrimp's dactyl club, with improved mechanical properties. Finite element analysis (FEA) and experimental characterisation of 3D printed polylactic acid (PLA) samples with bioinspired structures were performed to determine their compression and impact properties. The results showed that designing a bioinspired lattice with unit cells parallel to the load direction improved quasi-static compressive performance, among other lattice structures. The gyroid honeycomb lattice design of the insect forewings and mantis shrimp dactyl clubs outperformed the gyroid honeycomb design of the mantis shrimp shell, with improvements in ultimate mechanical strength, Young's modulus, and drop weight impact. On the other hand, hybrid designs created by merging two different designs reduced bending deformation to control collapse during drop weight impact. This work holds promise for the development of bioinspired lattices employing designs with improved properties, which can have potential implications for lightweight high-performance applications.

Low-velocity impact performance of integrally-3D printed continuous carbon fibre composite sandwich panels

Sandwich panels are heavily used in industrial sectors where specific mechanical properties are of utmost importance due to their high weight-stiffness ratio and energy absorption capacity. Lightweight sandwich cores with bio-inspired topologies have been used as an advanced alternative to conventional bulk cores to improve performance. Nowadays, sandwich structures comprised of core and skins are typically manufactured with two different processes and are afterwards adhesively joined together. Here, with a less time-consuming and more efficient assembly procedure in mind, an integrally 3D-printing strategy is proposed. This investigation analyses the low-velocity impact and quasi-static perforation performance of sandwich core designs inspired by the beetle's forewing trabecular structure. It was found that the core material was responsible of the rate dependence observed in the force–displacement curves. More complex finite element models than those employed here are necessary to capture all the fracture modes observed experimentally.

Energy-absorbing characteristics of hollow-cylindrical hierarchical honeycomb composite tubes under conditions of dynamic crushing

This paper presents an experimental and numerical study on the energy-absorbing characteristics of Biomimetic Multi-Cell Tubes (BMCTs), these being hollow-cylindrical-joint hierarchical honeycomb composite tubes inspired by the microstructural features of a beetle's forewing and geometrical features found in a spider's web. The BMCTs were fabricated using carbon fiber composites in optimized multi-tiered configurations. Low velocity crushing tests were conducted to characterize the load-displacement response, crashworthiness mechanisms, and energy absorption capacity of the BMCTs based on specific layer stacking sequences (LS). Additionally, the dynamic response of the BMCTs was modeled using the finite element analysis techniques.The predicted load-displacement relationships and failure modes show good agreement with the experimental results. Dynamic effects in the energy absorption characteristics of the tubes were evaluated. It is shown that the dynamic energy-absorbing capability of the BMCT-LS2 structure (Wall [±45/±30/±15]s Cylinder [±45/±30/±15/06]) is 6.5% higher than its quasi-static counterpart. In contrast, the SEA of BMCT-LS1 (Wall [+453/-453]s Cylinder [+453/-453/06]) is almost the same under both loading regimes. Finally, the quasi-static SEA of the plain circular tube is 13.8% lower than its dynamic counterpart. However, the SEA values of both BMCT-LS1 and BMCT-LS2 structures are 65% and 173% higher than the plain circular tubes, respectively.

Bio‐Inspired Homologous Magnesium‐Based Reflective Filters with Angular Heterochromatic Structural Colors

AbstractThe existing color filter implementation schemes are prone to introduce prestress during the preparation process due to the large difference in thermal expansion coefficients of different layers of materials, resulting in poor mechanical stability. Inspired by beetle forewings’ structure, it is proposed to construct asymmetric Fabry–Perot (F‐P) angular heterochromatic structural colors utilizing homologous materials through a continuous deposition method of magnetron sputtering technology. The fabricated large‐area F‐P‐type reflective filters not only exhibit high color saturation but also achieve good bonding ability between the layers with a steady‐state friction coefficient of ≈0.1. The large‐area reflective filter can achieve different colors such as blue, yellow, violet, and green, which is in agreement with the simulation results. This work not only provides a new design method for advanced decorative applications but also provides protection to the substrate.

Transcriptomic exploration of the Coleopteran wings reveals insight into the evolution of novel structures associated with the beetle elytron.

The acquisition of novel traits is central to organismal evolution, yet the molecular mechanisms underlying this process are elusive. The beetle forewings (elytra) are evolutionarily modified to serve as a protective shield, providing a unique opportunity to study these mechanisms. In the past, the orthologs of genes within the wing gene network from Drosophila studies served as the starting point when studying the evolution of elytra (candidate genes). Although effective, candidate gene lists are finite and only explore genes conserved across species. To go beyond candidate genes, we used RNA sequencing and explored the wing transcriptomes of two Coleopteran species, the red flour beetle (Tribolium castaneum) and the Japanese stag beetle (Dorcus hopei). Our analysis revealed sets of genes enriched in Tribolium elytra (57 genes) and genes unique to the hindwings, which possess more "typical" insect wing morphologies (29 genes). Over a third of the hindwing-enriched genes were "candidate genes" whose functions were previously analyzed in Tribolium, demonstrating the robustness of our sequencing. Although the overlap was limited, transcriptomic comparison between the beetle species found a common set of genes, including key wing genes, enriched in either elytra or hindwings. Our RNA interference analysis for elytron-enriched genes in Tribolium uncovered novel genes with roles in forming various aspects of morphology that are unique to elytra, such as pigmentation, hardening, sensory development, and vein formation. Our analyses deepen our understanding of how gene network evolution facilitated the emergence of the elytron, a unique structure critical to the evolutionary success of beetles.

Dynamic crushing performance of bio-inspired sandwich structures with beetle forewing cores

A novel design of Sandwich Structure inspired by Beetle Forewing (SSBF) is proposed in this study by mimicking the internal structure of beetle forewing. The viscoelastic material and the arch shape of hollow cavity structures found inside the forewing structure of the beetle are imitated by utilising the shear thickening fluid (STF) and semi-arch cores, respectively. The coupling interaction between fluid and structural components is analysed using a fluid-structure interaction (FSI) technique in LS-DYNA. It is found that the proposed SSBF by partially filling the core with STF generates a higher mean crushing force and stabilises the crushing force-displacement profile without a noticeably high initial peak crushing force as compared with the empty, polyurethane (PU) foam-filled, or Newtonian viscous fluid-filled counterparts. Furthermore, this stable crushing force of SSBF enhances with the increase of crushing speed, showing ideal behaviour for energy absorption and crushing resistance for the adaptation to the design of structures to resist impact loads.

Elastic deformability and zero Poisson’s ratio within a novel structure inspired by the gardenia from nature

Previous studies used to take the regular configuration as the element of the cellular structures, then carry out geometric optimization on the initial structures. Nowadays, more and more bionic metamaterial have been studied for their unique properties, such as bionic honeycomb tubular nested structure, bionic sinusoidal honeycomb, butterfly honeycomb, bamboo and beetle forewing thin-walled structures. Here, we report a novel gardenia-shaped honeycomb (GSH) by observing the gardenia from nature. Two valuable mechanical properties within GSH were explored in this study, which can simultaneously provide good deformability and zero Poisson’s ratio effect. To understand the mechanical properties of GSH, we show by theoretical, numerical, and experimental methods where is a good agreement. The developed theoretical models for calculating the in-plane elastic modulus are based on Euler-Bernoulli beam theorem and energy principle. The numerical and experimental tensile process at coincident strain were captured to strongly show the deformability of GSH. The findings of this study provide essential guidance for the design of GSH structures with the desired mechanical properties.

Review of carbon fiber-reinforced sandwich structures

This paper first reviews the research progress of carbon fiber-reinforced sandwich plates with grid cores, truss cores, and foam cores, and the results can be summarized in the following four points. 1) The load-bearing capacity and energy absorption capacity of grid-core and foam-core structures under bending loads have been improved by toughening with short fibers and Z-pinned fibers. 2) The progressive buckling mode of the core layer under compressive loading can significantly improve the energy absorption capacity of a sandwich structure. 3) The compressive failure of a truss-core sandwich structure is closely related to the strength at the nodes. 4) Following a literature review, this paper discusses the existing problems in sandwich structures and the corresponding countermeasures, and the results can be summarized in the following two points. 1) After implementing the current toughening measures, the debonding is improved to a certain extent; however, this approach does not prevent debonding. 2) No method has been presented that can increase the strength of the end nodes in truss-core members. Therefore, it is encouraging that a trabeculae/honeycomb-core sandwich structure composed of fiber-reinforced proteins—mimicking the biological structure found in a beetle forewing—can effectively solve the abovementioned problems.

Numerical study on impact resistance of novel multilevel bionic thin-walled structures

Inspired by impact-resistant hedgehog spine and beetle's forewing, the thin-walled structures of simple hedgehog spine and multilevel hedgehog spine were designed. Numerical simulations of rigid flat plate impacting on thin-walled structures showed that the deformation coordination ability and stress distribution of the structure are improved effectively by the hedgehog spine section design. This makes the specific energy absorption of the simple hedgehog spine thin-walled structure just before failure increase to 9.6 times and 5.7 times those of the single-walled cylinder and simple spider web thin-walled structures, respectively. Furthermore, the sub-circle multilevel design was introduced to further increase the range of high strain energy density, and the specific energy absorption of the multilevel hedgehog spine thin-walled structure was 2.1 times that of the simple hedgehog spine thin-walled structure.

Energy-absorbing characteristics of hollow-cylindrical hierarchical honeycomb composite tubes inspired a beetle forewing

This paper investigates the superior energy-absorbing characteristics of hollow-cylindrical-joint hierarchical honeycomb composite tubes under axial quasi-static crushing. Biomimetic multi-cell tubes (BMCTs), inspired by the forewing of a beetle, were manufactured using the vacuum bag moulding method. Quasi-static compression tests were conducted to characterize the force–displacement response, the progression of failure, the crashworthiness characteristics, and the corresponding energy absorbing mechanisms. The experimental results show that the fiber orientation (α) has a significant effect on the energy-absorbing characteristics of these structures. The crush load efficiency (CLE) and specific energy absorption (SEA) tend to initially decrease and then increase with increasing α. It has also shown that the SEA of the BMCTs can be significantly affected by employing different fiber orientations. The highest SEA value measured on these structures, 77.3 J/g, is more than double of 34.9 J/g measured on the single circular tube counterpart. The energy-absorbing capacity of the composite structures is devisable and can be enhanced by integrated biomimetic design.

The 3D lightweight structural characteristics of the beetle forewing: Verification

To practically and effectively develop lightweight and high-strength biomimetic materials based on the beetle forewing, the mechanical properties and failure mechanism of the pure-trabecular beetle elytron plate (TBEP) model and the “false biomimetic proposition” horizontal tube (HT) model mentioned in a previous paper were investigated through compression experiments in this paper. The results show that: the TBEP model has excellent compression performance and the strength/mass ratio of the HT model is even less than that of the honeycomb plate. This is because the existing horizontal tubes in the HT model have applied lateral force to the trabeculae, causing the horizontal tubes and trabeculae to form cracks at their contact due to their mutual pressing. Meanwhile, the horizontal tubes do not help prevent the deformation of the trabecula in the TBEP model, including bulging or shrinkage at the ends. This study provides an experimental and theoretical basis for the reader to identify the series of “false biomimetic propositions” appearing in the field of beetle forewing biomimetic structures; additionally, it will play an active role in preventing the abuse of bionics concepts and purifying the academic environment. It also provides direct guidance for the future development of durable, high compression resistance, lightweight and high-strength materials.

Crushing characteristics of bionic thin-walled tubes inspired by bamboo and beetle forewing

Bionic structures have garnered considerable attention due to their superior energy absorption capacity and light weight. This study proposes a group of bionic thin-walled tubes inspired by the microstructure of bamboo and beetle forewing. Experimental testing is conducted to validate the finite element model of bionic thin-walled tubes. The crushing performance of bionic thin-walled tubes and traditional thin-walled tubes is compared under the same weight. The bionic thin-walled tube with excellent crashing performance is further determined, that is, B-9-W. Then, parametric studies of the B-9-W tube are performed to reveal the effect of geometric parameters on crashworthiness characteristics. Finally, multi-objective optimization is carried out to seek the optimal design of B-9-W. Results show that, compared with two traditional thin-walled tubes, the specific energy absorption of the optimized B-9-W increases by 44.124% and 125.058%, respectively.

Mechanical performance of a beam with corrugated steel webs inspired by the forewing of Allomyrina dichotoma

This study used scanning electron microscopy (SEM) to observe the internal structure of forewings from adult male Allomyrina dichotoma. The images showed that the Allomyrina dichotoma forewing is a composite sandwich structure composed of upper and lower stressed skins, a hollow core layer and an abdominal-wall layer. The core layer has an irregular honeycomb-like structure with columellae; the chitin fibers on the surfaces of these columellae are connected to the upper and lower stressed skins. The structure of corrugated steel web (CSW) bridges is similar to that of a beetle forewing: the top and bottom concrete plates are similar to the upper and lower stressed skins, whereas the CSWs are similar to the irregular thin-walled core layers. In engineering applications, CSWs are prone to buckling. However, beetle forewings have a lightweight, high-strength composite structure that can adapt to complex, variable natural environments and external loads without breaking due to the reinforced columellae inside the structure. Hence, this work studied the microstructure of beetle forewing in an attempt to design a CSW with a columellar structure similar to that found in the core layer of the forewing. Moreover, a finite element model was used to quantitatively analyze the effects of the columellae on the deformation, shear stress distribution and buckling stability of CSW bridges, which can provide a reference for the bionic structure of a beetle forewing and for the optimization of CSW bridges.

Analysis of microstructure characteristics and mechanical properties of beetle forewings, Allomyrina dichotoma.

In this study, the internal microstructure of the forewings of Allomyrina dichotoma is investigated by scanning electron microscopy (SEM) analysis. The results of SEM test show that the inner microstructure of the forewings possesses an integrated sandwich-like plate supported by trabeculae, which is composed of upper and lower skins of unequal thicknesses, and a honeycomb core with trabeculae. Beetle forewing is a natural composite material composed of chitin fibres and proteins. Also, based on the micro dimensions of the forewings observed by SEM, two groups of micro finite element (FE) models of the forewings (i.e., core with trabeculae and core without trabeculae) are established to compare and comprehensively understand the effect of trabeculae on the mechanical properties of the forewings. The FE simulation results demonstrate that the trabeculae could effectively (1) improve the stress state on the upper skin, lower skin, and core layer of the forewings, (2) improve the overall bending stiffness of the forewings, (3) enhance the peeling resistance between the skins and core layer, and (4) improve the buckling strength of the thin-walled core layer. The unique forewing structure of the Allomyrina dichotoma can provide an excellent bionic model for optimizing the traditional honeycomb panel structure.

Preparation and impact resistance performance of bionic sandwich structure inspired from beetle forewing

The beetle has evolved over several hundred million years and possess perfect structure, as well as performance. According to the excellent structure and performance of beetle forewing, a bionic structural material (BSM) was designed and manufactured to improve its low-velocity impact resistance behavior. The surface layer of BSM is carbon-fiber-reinforced plastic (CFRP), and the cores of BSM are aluminum honeycomb. This study aims to investigate the dynamic response, energy absorption, and damage characteristics of BSM in low-velocity and high-cycle impact condition. Results showed that the BSM is superior to single CFRP, with lower peak force, higher energy absorption, and deformation. The damage mechanism of CFRP under cycling low kinetic energy is delamination and then fracture. Meanwhile, the damage of CFRP in sandwich structures is lower than in single CFRP, indicating an excellent impact resistance behavior of BSM, which is useful for practical engineering applications.

Thermal Protective Properties of the Allomyrina dichotoma Beetle Forewing for Thermal Protection Systems

ABSTRACTThis paper studies the heat-shielding performance of a beetle forewing to explore how it has excellent thermal protective properties. With an experimental setup of a self-developed heating environment, the heat transfer characteristics of the beetle forewing were tested at 50°C under steady state conditions. Two types of the forewings are considered: cut wing and live wing. The heat transfer results show that the live forewing provides a good heat-shielding performance with the heat-shielding index stabilizing at around 22.1%, which is 60% higher than that of the cut wing. Based on scanning electron microscope images of the microstructure of the cross section of the beetle forewing, a simplified finite element analysis is performed to numerically calculate the heat transfer properties of the forewing. The numerical simulations reveal that the proposed structure of the forewing is good for the design of an effective thermal protection system. In addition, the uncertainty analysis is performed to evaluate the quality of experimental data. These results provide a foundational understanding of the heat transfer characteristics of beetle forewing, which will inspire a promising candidate for an actively cooled thermal protection systems.

Biomimetic research on beetle forewings in twenty years: Internal structure, model and integrated honeycomb plates

This work reviewed the twenty years of history that the author is engaged in the biomimetic research on beetle forewings: at prophase (1997–2007), that the beetle forewings possessing the lightweight structures with a core layer composing of the hollow trabeculae and voids and variable cross-sectional sealing edge was mainly proposed, which can obtain the required bending modulus and moment of inertia; the A. dichotoma forewings are non-equiangular laminated structure and have the anisotropic tensile strength; the distribution of trabeculae in whole forewings was obtained for the first time, and the peeling test of forewings was performed, which experimentally demonstrated that the root of trabeculae have the function of converting the stripping failure to fiber tensile fracture, thus it has strong anti-stripping mechanical properties; meanwhile, a model of trabeculae with the core of protein and three dimensional structure model of trabeculae (hollow)-honeycomb was presented at the same time, the different design methods and biological significance of forewing structure in male and female A. dichotoma and P. Inclinatus were illuminated; at metaphase (2008–2015), the preparation technology of integrated honeycomb plates was mainly developed, the concept and model of full integrated honeycomb plates was proposed, the influence of the multi-body forming, short fiber reinforcement material, processing holes and trabeculae on the mechanical behavior of biomimetic samples were qualitatively investigated, the superiority of the biomimetic integrated honeycomb plates was confirmed; the influence of the previous research results on peers was pointed out, meanwhile some problems existing at prophase and the latest research progress (2015–2017) were briefly introduced. The work not only fully verified the first induction of author toward the beetle forewings with lightweight and high-strength structure, but also incisively and vividly showed the elegant appearance of beetle forewings as the paragon of lightweight and high-strength structural optimization design.

Investigation of punch resistance of the Allomyrira dichtoloma beetle forewing

In this study, the punch resistance of the beetle forewing was investigated to address the ability of the forewing against the external force. The punch resistance of the forewing was measured for different sizes and sexes of beetles using a conventional testing method in conjunction with the Digital Image Correlation (DIC) technique. The results showed that the maximum fracture load was measured around 23 N for the female beetle and around 20.2 N for the male beetle in the front-side punch test. Moreover, the fracture load in the front-side punch test was higher than that in the back-side punch test for both male and female beetles. This means that the beetle forewing plays a protection role against external loads. Furthermore, the puncture energy in the front-side punch test for the female beetle (6.91 mJ) was a little higher than that for the male beetle (5.27 mJ). In addition, the DIC results revealed that the first crack occurred along the trachea line and the second crack then appeared in the direction that was perpendicular to the direction of the first crack. This study provides a comprehensive understanding of the mechanical protection properties of the beetle forewing and offers a good lesson for studying lightweight bio-inspired composite material.

Crashworthiness design for bio-inspired multi-cell tubes with quadrilateral, hexagonal and octagonal sections

Multi-cell tubes have been widely used in vehicle engineering for their excellent energy absorption capacity. In this paper, a group of bionic multi-cell tubes (BMCTs) with quadrilateral, hexagonal and octagonal sections were proposed. The BMCTs were constructed by filling the cylindrical tubes into different position of multi-cell tubes (MCTs), which was inspired by the microstructure of beetle forewings. The finite element (FE) models under axial impact loading were established and then validated by the Simplified Super Folding Element (SSFE) theory. The crashworthiness of different BMCTs and MCTs was compared, and the results showed that the sixth type of bionic multi-cell tube with octagonal section (O-BMCT-6) has the best crashing performance. Then, the multiobjective optimization design of O-BMCT-6 was conducted by using non-dominated sorting genetic algorithm II (NSGA-II) and radial basis function (RBF) metamodels. The optimal O-BMCT-6 showed superior crashworthiness and could be used as an energy absorber.

Structural characteristics of the core layer and biomimetic model of the ladybug forewing

To explore the characteristics of the core structure of ladybug (Harmonia axyridis) forewings, their microstructure was studied using microscopes. The results suggest that trabeculae exist in the frame of the beetle (ladybug) forewing for the first time; this study represents the first determination of the parameters N, the total number of trabeculae in each forewing, and λt, the ratio of the cross-sectional area of the trabeculae to the effective area of trabecular distribution. The cross-sectional area of a single trabecula in the ladybug forewing is smaller than those in two other kinds of beetles, Allomyrina dichotoma and Prosopocoilus inclinatus. However, the average trabecular density of the ladybug forewing is 84 per square millimeter, which is the highest among these three kinds of beetles. The λt values are 1.0%, 1.5% and 10.5% for H. axyridis, A. dichotoma and P. inclinatus, respectively, and the corresponding N values are approximately 1.4, 1.7 and 3.7 thousand, respectively. Based on these findings, a biomimetic model of the ladybug forewing is proposed, which is characterized by a core structure with a high-density distribution of thin trabeculae surrounded by a foam-like material.