Bionic Structure Research Articles

Crashworthiness analysis of okra biomimetic corrugated multi-cellular structure

This study introduce an innovation okra biomimetic corrugated multi-cellular Taper tube (OBCMT) designed for the energy absorption, drawing inspiration from the okra, which comprises a Fourier curve wall and X-shaped ribs. Validation is accomplished through quasi-static crushing experiments, ensuring the accuracy of the finite element simulation model. Numerical simulations investigate the influence of critical interaction structural parameters on the performance of the OBCMT, and a theoretical model based on the super folding theory is deduced to predict the mean crushing force of the OBCMT. The result show that the specific energy absorption(SEA) exhibited the heightened sensitivity to the variation of C_height under the same C_R, approximately reached 8.36 kJ/kg which increased by 43.2 % compared to the minimum value in the identical group. Simultaneously, the structure parameters of height coefficient(C_height) and radiu coefficient(C_R) have the most significant impact on the deformation mode of OBCMT. Comparative analysis demonstrates that the OBCMT exhibits the extraordinal crashworthiness compared to the contemporary typical energy absorption structures under identical mass, with the SEA reaching 21.8 kJ/kg. This represents approximately 290.7 %, 205.7 %, 187.9 %, 189.6 %, and 174.4 % relative to the six-cell hexagonal tube (SHT), quadruple-cell circular tube (QCT), multi-cell bicircular tube (MBT), five-cell square tube (FST), and quadruple-cell square tube II (QST_Ⅱ), respectively. This research significantly advances the development of high-performance bionic energy-absorbing structures for crash applications and enhances our comprehension of the biomimetic engineering.

Study on the multi-environmental wear resistance of a shell-imitating multilayer multimaterial composite carbon fiber

Aiming at the serious wear problem of steel matrix of heavy-duty synchronizer rings, this article inspired by the shell hierarchical-structure to resist abrasion and the high adhesion of tree frog, realized the adhesion between steel and carbon-fiber by constructing the imitation tree frog structure, and deposited calcium and nickel on the carbon-fiber surfaces to form steel/carbon fiber/calcium-nickel bionic hierarchical composites. The results showed that the shear strength of bionic hierarchical composites enhanced by about 214.3 %. The wear-resistance of the composites increased in dry, wet and oil environments, with optimal wear resistance in oil environment, and the wear rate reduced by about 0.657 * 10−12Kg•N−1•m−1. The steel/carbon fiber/calcium-nickel bionic hierarchical structure is valuable for improving the multi-environmental wear resistance of the composites.

Tensile properties of helical carbon fiber tows

The carbon fiber used in the load-bearing structural components often exhibits a relatively low toughness and a limited elongation at the point of failure within its carbon fiber tows. To address this challenge, we introduced a bionic helical structure as an innovative alternative to the conventional straight carbon fiber tows, resulting in a novel material characterized by enhanced strength and toughness. Pioneering a theoretical model, we delved into the effects of the helical angle on the tensile mechanical properties of helical carbon fiber tows for the first time. Subsequently, we conducted experimental trials to validate our theoretical findings and identified an optimal range for the helical angle. The optimized helical angle enhances additional lateral interactions, improving the bonding between the fibers and the resin. The characteristics of the helical structure increase the overall fracture elongation of the fiber tows. Tensile tests revealed a remarkable 10.8 % increase in maximum tensile strength and a significant 46 % enhancement in toughness when the tows were fully impregnated with epoxy resin using this optimal helical angle. Incorporating the helical structures at this optimized angle represents a breakthrough in improving the mechanical properties of carbon fiber tows, offering a unique solution to strike a balance between strength and toughness in carbon fiber composites.

Design and additive manufacturing of bionic hybrid structure inspired by cuttlebone to achieve superior mechanical properties and shape memory function

Lightweight porous materials with high load-bearing, damage tolerance and energy absorption (EA) as well as intelligence of shape recovery after material deformation are beneficial and critical for many applications, e.g. aerospace, automobiles, electronics, etc. Cuttlebone produced in the cuttlefish has evolved vertical walls with the optimal corrugation gradient, enabling stress homogenization, significant load bearing, and damage tolerance to protect the organism from high external pressures in the deep sea. This work illustrated that the complex hybrid wave shape in cuttlebone walls, becoming more tortuous from bottom to top, creates a lightweight, load-bearing structure with progressive failure. By mimicking the cuttlebone, a novel bionic hybrid structure (BHS) was proposed, and as a comparison, a regular corrugated structure and a straight wall structure were designed. Three types of designed structures have been successfully manufactured by laser powder bed fusion (LPBF) with NiTi powder. The LPBF-processed BHS exhibited a total porosity of 0.042% and a good dimensional accuracy with a peak deviation of 17.4 μm. Microstructural analysis indicated that the LPBF-processed BHS had a strong (001) crystallographic orientation and an average size of 9.85 μm. Mechanical analysis revealed the LPBF-processed BHS could withstand over 25 000 times its weight without significant deformation and had the highest specific EA value (5.32 J·g−1) due to the absence of stress concentration and progressive wall failure during compression. Cyclic compression testing showed that LPBF-processed BHS possessed superior viscoelastic and elasticity energy dissipation capacity. Importantly, the uniform reversible phase transition from martensite to austenite in the walls enables the structure to largely recover its pre-deformation shape when heated (over 99% recovery rate). These design strategies can serve as valuable references for the development of intelligent components that possess high mechanical efficiency and shape memory capabilities.

Preparation and investigation of high-performance flexible and transparent Ag/PDMS substrate with the bionic structure of cicada wings

In this study, an efficient, homogeneous, flexible and transparent Ag/Polydimethylsiloxane (PDMS) substrate with an orderly three-dimensional nanopillar structure was proposed. Ag NPs were thermally deposited on the flexible bionic PDMS support obtained by a two-step replication of cicada wings. Scanning electron microscope images reveal when the deposition time was 50 min, Ag NPs of proper size densely covered the entire PDMS nanopillar surface in the Ag-50/PDMS substrate. Both the gaps between the Ag NPs and those between the nanopillars acted as efficient electric field amplifiers. The enhancement factor (EF) of the Ag-50/PDMS substrate was calculated to be 2.89 × 107 by using crystal violet as the probe molecule. The Ag-50/PDMS substrate also exhibited good uniformity and reproducibility with a relative standard deviation of 1.46% and 11.45% respectively. The detection capability of the proposed flexible and transparent Ag-50/PDMS substrate in practical applications was demonstrated by the in-situ detection of 0.1 ppm malachite green on fish surfaces, indicating its great potential in the field of food monitoring.

Bionic noise reduction design of axial fan impeller

Fans are integral equipment widely employed in both industrial settings and daily life. However, a persistent challenge in fans design lies in the inherent conflict between aerodynamic performance and noise levels. Improving aerodynamic efficiency often results in a compromise of acoustic performance. To tackle this issue, we employed the bionic design method to craft a novel axial fan impeller featuring a bionic curved hub and bionic serrated leading edges. The impact of structural optimization on the aerodynamic and acoustic properties of the impeller, as well as the influence of optimization parameters on these properties, were systematically investigated through numerical simulations. The bionic impeller was then fabricated using 3D printing, and the aerodynamic and noise performance of the impeller were experimentally evaluated by integrating it into an external air conditioner. Comparison of the flow field and sound field data between the optimized and prototype impellers revealed noteworthy outcomes. The curved wall at the bionic hub’s tail effectively diminished the pressure gradient on the hub surface, directing the airflow toward the rear end of the hub. This design enhancement significantly reduced the turbulent area behind the prototype impeller’s hub. Additionally, under the appropriately designed, the bionic serrated structure could effectively reduce the contact area between the blade’s leading edge and incoming flow. This led to the dispersion of stress concentrations and the inhibition of strong turbulence generation. Notably, the experimental results indicated a 3.7% increase in air volume flow rate and a 2.3 dB reduction in noise for the optimized impeller compared to the prototype. This successful mitigation of the trade-off between aerodynamic performance and noise level underscores the effectiveness of our bionic design approach.

Experimental Study on Aerodynamic Characteristics of Downwind Bionic Tower Wind Turbine.

The vibrissae of harbor seals exhibit a distinct three-dimensional structure compared to circular cylinders, resulting in a wave-shaped configuration that effectively reduces drag and suppresses vortex shedding in the wake. However, this unique cylinder design has not yet been applied to wind power technologies. Therefore, this study applies this concept to the design of downwind wind turbines and employs wind tunnel testing to compare the wake flow characteristics of a single-cylinder model while also investigating the output power and wake performance of the model wind turbine. Herein, we demonstrate that in the single-cylinder test, the bionic case shows reduced turbulence intensity in its wake compared to that observed with the circular cylinder case. The difference in the energy distribution in the frequency domain behind the cylinder was mainly manifested in the near-wake region. Moreover, our findings indicate that differences in power coefficient are predominantly noticeable with high tip speed ratios. Furthermore, as output power increases, this bionic cylindrical structure induces greater velocity deficit and higher turbulence intensity behind the rotor. These results provide valuable insights for optimizing aerodynamic designs of wind turbines towards achieving enhanced efficiency for converting wind energy.

One-step laser preparation of unidirectional liquid spontaneous transport structures

The Tilted Wedge Microcavity Array (TWMA) structure of the Nepenthes alata peristome allows for unidirectional fluid transport without any surface energy gradient. However, current methods of creating bionic Nepenthes alata peristome structures have significant improvement room in terms of structural shape, machining efficiency, and cost-effectiveness. To address these issues, in this paper, bionic Nepenthes alata peristome TWMA structures on 7075 aluminium alloy was built via a nanosecond laser with highly efficiency, low cost and flexible processing pattern. A unilateral tilted microcavity structure was fabricated by designing the laser processing path, and at the same time, the samples were tilted to change the angle at which the laser beam hit the working surface. This ensures that the microcavity is machined without destroying the microcavity structure underneath. The variation law of aluminum alloy ablation threshold under the influence of laser incidence angle was studied. The dimensional parameters of the TWMA structure were analysed in relation to laser incidence angle θ, laser processing power P, number of laser scans n, and laser scanning speed V. Additionally, liquid spreading tests were carried out on different surfaces of bionic structures, and the influence of surface wettability on the spreading results was investigated. The results indicate that the ablation threshold decreases initially and then increases with an increase in the laser incidence angle. This reflects the trend of the aluminium alloy absorption rate, which initially increases and then decreases with an increase in the incidence angle. For the prepared TWMA structure, the optimum speed of achieving the unidirectional spreading effect was found to be 2.41 mm s−1 with a surface contact angle (CA) of 35°. This study presents a low-cost and rapid preparation method for creating liquid unidirectional transport structures without any energy input.

Study on the tensile properties of 3D printing cell structure based on fractal theory

Abstract Using lightweight technology involves optimizing materials, structures, and manufacturing processes to reduce structural weight while meeting performance standards. This technology has emerged as pivotal in advancing the next generation of aerospace equipment. This study employed the 3D printing method using PLA material to produce tensile test specimens of three structures: the concave hexagonal, bionic feather, and standard structures. Tensile and finite element simulation tests were conducted to assess their tensile properties. By comparing crack propagation paths under tensile load, the impact of these paths on structure fracture toughness was analyzed using fractal theory. The findings reveal that distinct structures exhibit varied fracture toughness due to differing crack propagation paths during tensile fracture. Fractal dimensions were calculated for each structure: 1.491 for the concave hexagonal structure, 1.488 for the bionic feather structure, and 1.465 for the standard structure. These dimensions suggest that the concave hexagonal structure possesses the highest fracture toughness among the three structures.

Drag reduction characteristics of the placoid scale array skin sup-ported by micro Stewart mechanism based on penalty immersed boundary method

Sharkskin performs an excellent flow drag reduction property, leading to numerous biomimetic research to obtain artificial drag reduction structures for underwater vehicles. The existing work mainly focused on replicating or simplifying the morphology of the placoid scale, however, such bionic structures cannot fully reproduce the drag reduction effects of sharks swimming in natural environments. This is because the existing research has not considered the influence of the multi-degree freedom motion characteristics of the placoid scale. Therefore, a new bionic drag reduction skin is proposed by combining micro Stewart mechanisms and placoid scales, where the micro Stewart mechanism is able to achieve the multi-degree freedom motion characteristics. The numerical results indicate that micro Stewart mechanisms inhibit the generation and development of the streamwise and spanwise vortex structures in the bionic placoid scale array, which can delay flow separation and improve the drag reduction effect of the placoid scale array. Compared with the bionic placoid scale skin and the blade groove skin without multi-degree freedom motion foundation, the new bionic skin achieves relative drag reduction efficiency of 15.78 % and 14.18 % at maximum, respectively, by reasonably adjusting the bionic skin parameters including the leg stiffness, leg damping, upper platform mass, upper platform center of mass height of the micro Stewart mechanism and the skin element distribution spacing. The research presents a novel sharkskin bionics design and reveals the mechanism of skin drag reduction to some extent.

Spider-silk-inspired strong and tough hydrogel fibers with anti-freezing and water retention properties

Ideal hydrogel fibers with high toughness and environmental tolerance are indispensable for their long-term application in flexible electronics as actuating and sensing elements. However, current hydrogel fibers exhibit poor mechanical properties and environmental instability due to their intrinsically weak molecular (chain) interactions. Inspired by the multilevel adjustment of spider silk network structure by ions, bionic hydrogel fibers with elaborated ionic crosslinking and crystalline domains are constructed. Bionic hydrogel fibers show a toughness of 162.25 ± 21.99 megajoules per cubic meter, comparable to that of spider silks. The demonstrated bionic structural engineering strategy can be generalized to other polymers and inorganic salts for fabricating hydrogel fibers with broadly tunable mechanical properties. In addition, the introduction of inorganic salt/glycerol/water ternary solvent during constructing bionic structures endows hydrogel fibers with anti-freezing, water retention, and self-regeneration properties. This work provides ideas to fabricate hydrogel fibers with high mechanical properties and stability for flexible electronics.

Fabrication of a Triple-Layer Bionic Vascular Scaffold via Hybrid Electrospinning.

Tissue engineering aims to develop bionic scaffolds as alternatives to autologous vascular grafts due to their limited availability. This study introduces a novel wet-electrospinning fabrication technique to create small-diameter, uniformly aligned tubular scaffolds. By combining this innovative method with conventional electrospinning, a bionic tri-layer scaffold that mimics the zonal structure of vascular tissues is produced. The inner and outer layers consist of PCL/Gelatin and PCL/PLGA fibers, respectively, while the middle layer is crafted using PCL through Wet Vertical Magnetic Rod Electrospinning (WVMRE). The scaffold's morphology is analyzed using Scanning Electron Microscopy (SEM) to confirm its bionic structure. The mechanical properties, degradation profile, wettability, and biocompatibility of the scaffold are also characterized. To enhance hemocompatibility, the scaffold is crosslinked with heparin. The results demonstrate sufficient mechanical properties, good wettability of the inner layer, proper degradability of the inner and middle layers, and overall good biocompatibility. In conclusion, this study successfully develops a small-diameter tri-layer tubular scaffold that meets the required specifications.

Towards eco-friendly plant growth regulator: A robustly stable and efficient uniconazole emulsion based on onion-like lamellar liquid crystal

As a commonly water-based pesticide formulation, conventional Emulsions in Water (EWs) always suffer from demulsification in actual complex environments and burst release due to their thermodynamic instability. The ecotoxicity and phytotoxicity caused by chemosynthetic adjuvants cannot be ignored. To address these issues, herein, using a soybean lecithin-based lamellar liquid crystal emulsion (LCE) as the carrier, we construct a robustly stable and low-toxicity EW with the “onion-like” bionic structure and achieve the efficient delivery of plant growth regulator (PGR) uniconazole (UZ). The hydrophobic UZ is firmly encapsulated within the orderly assembled Oil-in-Liquid Crystal-in-Water (O/LC/W) multilayers. This confinement endows UZ-LCE with robust stability, even while encountering disturbances such as dilution, shaking, and changes in pH, ions, and temperature. Furthermore, UZ-LCE exhibits enhanced wettability and affinity to foliar surfaces, as well as specific sustained-release ability. Owing to these superiorities of UZ-LCE, during two consecutive years of efficacy evaluations in cotton field experiments, UZ-LCEs administered through drip irrigation and foliar spray demonstrate remarkable enhancements in controlling excessive plant growth, increasing chlorophyll content, and boosting flower bud formation, surpassing the effectiveness of conventional EWs. UZ-LCE even outperforms commercial preparations (WP and SC) in balancing vegetative growth and reproductive growth, resulting in an 8.3% increase in yield. This research provides an innovative pesticide formulation with eco-friendly adjuvants, less organic solvent, and synergistic functionalities, which is prospective to be extended to other pesticide EWs and contribute to sustainable agriculture.

Analysis of mechanical characteristics and permeability of TPMS and Voronoi porous structure for bone scaffold

Bionic porous structure has been widely used in the field of bone implantation, because it can imitate the topological structure of bone, reduce the elastic modulus of metal bone implantation, and meet the mechanical properties and material transmission characteristics after implantation. This paper mainly studies the effects of different bionic porous structures on the mechanical and material transport properties of bone scaffolds. Firstly, under the same porosity condition, 12 groups of bionic porous structures with different shapes were designed, including G, P, D, I-type three period minimal surface (TPMS) and Voronoi porous structures with different irregularities. Then uses ABAQUS to carry out mechanical finite element simulation on different bionic porous structures, and uses Ti-6Al-4V alloy as forming material, uses laser powder bed fusion technology (LPBF) to prepare the scaffold, then carries out compression experiments. At the same time, COMSOL software is used to simulate the flow characteristics, analyze the permeability characteristics, and verified through cell experiment in vivo. The results show that the mechanical and permeability are different with vary scaffolds. In terms of topology, the morphological characteristics of TPMS are similar to trabecular bone, its compressive strength is relatively strong. Voronoi scaffold has lower elastic modulus, which can provide sufficient mechanical support while reducing stress shielding. In addition, the permeability of TPMS scaffold is better than Voronoi scaffold, which is helpful to promote cell proliferation and bone ingrowth. These bionic porous structures have their own advantages. Therefore, when designing porous structures for bone implantation, it is necessary to select the appropriate porous structure according to different bone implantation requirements. The research will help promote the clinical application of porous structures in the field of bone implantation, and provide theoretical support for the exploration of bone implantation structure design.

High Sensitivity Triboelectric Based Flexible Self-Powered Tactile Sensor with Bionic Fingerprint Ring Structure.

Flexible self-powered tactile sensors, with applications spanning wearable electronics, human-machine interaction, prosthetics, and soft robotics, offer real-time feedback on tactile interactions in diverse environments. Despite advances in their structural development, challenges persist in sensitivity and robustness, particularly when additional functionalities, such as high transparency and stretchability. In this study, we present a novel approach integrating a bionic fingerprint ring structure with a PVDF-HFP/AgNWs composite fiber electrode membrane, fabricated via 3D printing technology and electrospinning, respectively, yielding a triboelectric nanogenerator (TENG)-based self-powered tactile sensor. The sensor demonstrates high sensitivity (5.84 V/kPa in the 0-10 kPa range) and rapid response time (10 ms), attributed to the microring texture on its surface, and exhibits exceptional robustness, maintaining electrical output integrity even after 24,000 cycles of loading. These findings highlight the potential of the microring structures in addressing critical challenges in flexible sensor technology.

A bionic strong nanostructured soy protein-based adhesive enabled antistatic and self-extinguishing wood-based composites

Wood composites represent one kind of sustainable functional materials for interior decoration and packaging, but their tendency to generate static electricity poses discomfort and potential fire hazards. To address this huge challenge, we herein report a strong, conductive, nanostructured formaldehyde-free soy protein-based adhesive by mixing nanocellulose and tannic acid functionalized MXene, and soy protein, which is then used to create antistatic and fire-extinguishing wood composites. The resulted soy protein-based adhesive exhibited an exceptional bonding capability due to its bionic organic-inorganic hybridized crosslinking structure. With this soy protein-based adhesive, as-prepared wood composites achieved a static flexural strength of 14.08 MPa, meeting the demanding interior use requirement. Because of the presence of both MXene and quaternary ammonium salt in the adhesive, the resultant wood composite shows an electrical resistance of 3.123 × 109 Ω·cm, satisfying the antistatic requirements for wood-based composites, and a desired self-extinguishing ability. This work offers a promising strategy to create strong nanostructured bio-adhesive, which can be used for producing multifunctional wood composites as decoration and packaging materials.

Mechanical and Bionic Structure Characteristics of Clamp-grip and Web-claw Suction Cup Submersible Pipeline Robot

Mechanical and Bionic Structure Characteristics of Clamp-grip and Web-claw Suction Cup Submersible Pipeline Robot

In-Plane crushing performance of bionic glass Sponge-Type honeycomb structures

Honeycomb structures are commonly adopted due to their superior energy absorption capacity. In this study, a new bionic glass sponge–type honeycomb structure (BSH) with a quadrilateral octagonal mesh microstructure inspired by the sea sponge structure was proposed. The in-plane crushing performance of the BSH with different geometrical parameters under different crushing speeds was investigated by ABAQUS/Explicit. The numerical findings suggested that the BSH displayed stronger energy absorption in contrast to the square, hexagonal and hierarchical honeycombs at both quasi-static and dynamic crushing conditions. More plastic hinges and more unit walls involved in deformation resulted in a high energy absorption capacity. In addition, three typical deformation modes of the BSH under different loading speeds were discussed, and the empirical model to predict the plateau stress of the BSH was established based on the shock wave theory. Finally, the effect of boundary segmentation parameter m on crushing performance was also illustrated. The energy absorption capacity reaches a maximum at m = 3 for quasi–static loading, whereas at m = 5 for dynamic loading. These findings provide valuable insights into the optimization of bionic honeycombs.

Additive manufacturing as a resource-saving alternative in the manufacturing process of marine gearbox housing

ABSTRACT Marine gearbox housings are large components of several metres in length and tonnes of weight. The conventional manufacturing process is a time-consuming and elaborate process with the necessity to oversize the components from a load point of view. This results in a redundant amount of energy and resources for manufacturing. In contrast, wire arc additive manufacturing (WAAM) offers the possibility to realize a load- and weight-optimized design and provides an energy- and resource-efficient alternative in the manufacturing of marine gearbox housings. It has been shown that this additive manufacturing process provides the potential of 41% energy reduction and 36% material reduction compared to the iron cast manufacturing process. This is due to the modification of the load flow and the use of the hybrid manufacturing production as well as the possibility to include bionic structures in the gearbox design.

Thermal performance analysis of battery thermal management system utilizing bionic liquid cooling plates with differentiated velocity distribution strategy

Bionic channel liquid cooling plates (BC-LCPs) show high heat dissipation performance in battery thermal management system (BTMS), but suffer from the poor temperature-equalizing ability. Herein, a BTMS with novel BC-LCPs and differentiated velocity distribution strategy is proposed to overcome the low temperature uniformity, and balance the cooling performance and power consumption. The BC-LCPs are firstly designed by precisely tailoring the series cobweb channels inspired by the bionic structures in the nature. Through systematic optimization combining single factor analysis with orthogonal test and complementary test, differentiated velocities (vI and vII) of 0.20 and 0.46 m∙s−1 are adopted, respectively. Ultimately, the LC system demonstrates exceptional cooling performance while maintaining lower energy consumption. For example, with a discharge rate of 3C and an environment temperature of 50 °C, the temperature and temperature difference of the battery pack are controlled synergistically below 30.9 and 4.47 °C, respectively. At the same time, the Ptotal can reach as low as 0.202 W, which is reduced by 42.0 % compared to the case with uniform velocity strategy.