Design Of Biomimetic Structures Research Articles

Recent advances to engineer tough basalt fiber reinforced composites: A review

AbstractBasalt fibers, known as “green materials without pollution in the 21st century”, have gained widespread attention due to its good mechanical properties. Basalt fiber‐based composites have applications in various fields such as construction, transportation, energy, and protection. However, as an inorganic fiber material, basalt fiber is hard and brittle and prone to catastrophic failure, reducing the safety of the material. Therefore, it is important to strengthen the toughness of basalt fiber‐based composites. This paper reviews the contributions made by researchers in recent years to enhance the toughness of basalt fiber reinforced composites. It mainly focuses on four aspects: physical and chemical modification of fibers surface, mixed application of multiple fibers, different textile and 3D printing technology, and design of biomimetic structures. Through these methods, the toughness of basalt fiber‐reinforced composite materials was increased by 10%–90%. In today's advocacy for green industrial development, the research and application of basalt fibers are very important for advancing the process of green development. These contributions can promote the application of basalt fiber in engineering fields.Highlights Basalt fiber is a green material without pollution. Basalt fiber reinforced composites is the key material for engineering field. Strengthening interfacial adhesion can significantly improve the toughness of composites. Basalt fibers can serve as an alternative to glass fibers in composite materials. The hybridization of basalt fibers with soft fibers can effectively enhance the toughness of composites.

An innovative three-dimensional printed titanium implant with a biomimetic structure design for promoting osseointegration potential

The present study aimed to investigate the surface characteristic, biocompatibility, and bone regeneration behavior of an innovative three-dimensional (3D) printed titanium (Ti) implant with a biomimetic cancellous bone-like spherical particle porous structure (3DBCP-Ti) through scanning electron microscopy, X-ray diffractometry, static contact angle goniometry, cytotoxicity assay, and rabbit model. The analytical results showed that the 3DBCP-Ti implant with an average pore size of 400 ± 10.5 μm can be fabricated using a selective laser sintering method. The 3DBCP-Ti implant not only possessed excellent wettability (13.5 ± 1.7°) but also presented superior cell viability (97 ± 1.5 %) in vitro. After implantation for 4 weeks, the bone mineral density of the 3DBCP-Ti implant (0.14 ± 0.02 mg/cm3) exhibited a slightly higher value than the control implant (0.13 ± 0.03 mg/cm3). Moreover, histological results also indicated that the new bone formation area of the 3DBCP-Ti implant (43.9 ± 7.0 %, *p < 0 0.05) significantly enhanced as compared with the control (23.5 ± 4.6 %) and blank (18.2 ± 1.4 %) groups at week 12 post-implantation. Accordingly, these findings demonstrate that the innovative 3DBCP-Ti implant has the potential to promote osseointegration at early-stage implantation for dental, orthopedic, and neurosurgical applications.

Experiment Investigation of the Compression Behaviors of Nickel-Coated Hybrid Lattice Structure with Enhanced Mechanical Properties.

The lattice metamaterial has attracted extensive attention due to its excellent specific strength, energy absorption capacity, and strong designability of the cell structure. This paper aims to explore the functional nickel plating on the basis of biomimetic-designed lattice structures, in order to achieve higher stiffness, strength, and energy absorption characteristics. Two typical structures, the body-centered cubic (BCC) lattice and the bioinspired hierarchical circular lattice (HCirC), were considered. The BCC and HCirC lattice templates were prepared based on DLP (digital light processing) 3D printing. Based on this, chemical plating, as well as the composite plating of chemical plating followed by electroplating, was carried out to prepare the corresponding nickel-plated lattice structures. The mechanical properties and deformation failure mechanisms of the resin-based lattice, chemically plated lattice, and composite electroplated lattice structures were studied by using compression experiments. The results show that the metal coating can significantly improve the mechanical properties and energy absorption capacity of microlattices. For example, for the HCirC structure with the loading direction along the x-axis, the specific strength, specific stiffness, and specific energy absorption after composite electroplating increased by 546.9%, 120.7%, and 2113.8%, respectively. The shell-core structure formed through composite electroplating is the main factor for improving the mechanical properties of the lattice metamaterial. In addition, the functional nickel plating based on biomimetic structure design can further enhance the improvement space of mechanical performance. The research in this paper provides insights for exploring lighter and stronger lattice metamaterials and their multifunctional applications.

Numerical characterization on mechanical performances of artificial cuttlebone-like structures produced via the generative adversarial network

Advanced manufacturing techniques eliminates constraints of time and cost associated with fabrications of complex structures, thereby significantly promotes the development of biomimetic lightweight structures. Currently, biomimetic structures are often simplified as periodic lattice structures, while the imitation of natural structures' random yet coherent arrangements is highly limited. This study utilizes a progressive algorithm called SinGAN, which is a modified version of GAN, to capture the inherent randomness presented in biostructures. In this paper, we focus on the ultralight cuttlebone structure, where SinGAN is conducted feature extractions and structural learning. The input for the process includes the 2D scanning images, which are then used to generate imitated structures through the network. The 2D images are vertically extruded to convert them into 3D structures for further analyses. The stiffness of all structures is determined through finite-element-based simulations. Computed results reveal that SinGAN successfully extracts the structural features of cuttlebone. In addition, some property of the imitated structures exhibits much more superior behavior comparing to the original structure. The presented approach for generating imitated structures is one of the first few endeavors to integrate artificial intelligence into biomimetic structure design, to the best of our knowledge.

The shape-retention and heat-tolerant elastic helix based on azobenzene-polyimide supramolecular assembly

Helical structures are ubiquitous in natural and engineered systems across multiple length scales, while they often exhibit nearly uniform radius and pitch. Utilization of biomimetic structure design to develop stretchable and robust 3D helical structures that are shape-preserving and heat-tolerant is of great interest. Herein, we devise flexible 3D helixes by supramolecular self-assembly and high voltage electric field orientation of molecular chains. The 3D helixes not only inherit buffering mechanics with exceptional shape-retention ability against cyclic stretching but also exhibit excellent heat-resistant quality. The results of the experimental tests confirm that the helix can recover its original shape without obvious residual strain and basically withstand after 2000 cycles under force loading of 10 cN. Such robust biomimetic materials hold great prospects in the fields of artificial muscles, wearable materials, and so on.

Marangoni-driven biomimetic salt secretion evaporator

Solar-driven steam generation is regarded as a sustainable strategy for high salinity wastewater treatment. However, the salt accumulation problems associated with vigorous water evaporation limit the practicality of solar evaporators. Herein, inspired by the salt secretion mechanism of natural mangrove leaves, a biomimetic salt secretion evaporator (BSSE) composed of a wood shell and photothermal hydrogel was designed to induce salt crystallization outside the steam generation interface during brine evaporation. Directional salt migration, secretion, and crystallization was driven through region-dependent inhomogeneous thermal and water evaporation management. This exceptional function endows BSSE with superior high-salinity brine evaporation (2.08 kg m−2 h−1, 20 wt% NaCl) and long-term salt rejecting (continuous operation 100 h without any post-cleaning treatment). Experiments characterization and numerical simulations provide a consistent result in which Marangoni convection induced by the thermocapillary and solute capillary effect formed in evaporation interface is the origin of dynamic salt secretion. Moreover, due to the salt secretion characteristics of biomimetic structure design, BSSE can effectively extract the salt from salinized soil and permanently reduce its internal salinity, which provides a logical solution for simultaneously solve global water and food problems.

DEM Simulation in Wear Performance of Four Typical Bionic Structures

In order to resist the abrasion of sand and gravel, shellfish such as arca subcrenala lischke and arca inflata reeve have evolved non-smooth surface morphology with high wear resistance. In this paper, four biomimetic structures of prismatic, conical, ball crown and stripd were designed to study the abrasive wear behavior of different biomimetic structures. Built on the Discrete Element Method (DEM), the DEM model and its abrasive wear calculation model are established. By analyzing the changes of the contact bond field of the abrasive wear system, the non-uniform evolution process and wear law of the abrasive wear process of the four bionic structures are obtained. The research in this paper provides a new research method and means for the numerical simulation of wear behavior of biomimetic structures and the optimal design of biomimetic structures based on the surface morphology of biological non-smooth wear-resistant bodies.

Biomimetic Design and Mass Production of Sustainable Multiscale Cellulose Fibers‐Based Hierarchical Filter Materials for Protective Clothing

AbstractAs a core part of personal protective equipment (PPE), filter materials play a key role in individual protection, especially in the fight against the COVID‐19. Here, a high‐performance multiscale cellulose fibers‐based filter material is introduced for protective clothing, which overcomes the limitation of mutual exclusion of filtration and permeability in cellulose‐based filter materials. With the hierarchical biomimetic structure design and the active surface of multiscale cellulose fibers, high PM2.5 removal efficiency of ≈92% is achieved with the high moisture transmission rate of 8 kg m−2 d−1. Through a simple and effective dip‐coating and roll‐to‐roll process, the hierarchical filter materials can be made on a large scale and further fabricated into high‐quality protective clothing by industrial production equipment.

Improvement of CrMoN/SiNx coatings on mechanical and high temperature Tribological properties through biomimetic laminated structure design

CrMoN/SiNx multilayered coatings were fabricated by controlling the shutter-open time of two sputtering guns in a radio frequency magnetron sputtering system. Employing the structure of nacreous shells from nature, nano-crystalline and amorphous monolayers were periodically stacked. CrMoN/SiNx thin films with different bi-layer periods were deposited on Si-wafer and Inconel-718 substrates. The phases of the coatings were examined using a grazing incidence X-ray diffraction (XRD) technique. Information of chemical composition was obtained by field emission electron probe micro-analyzer (FE-EPMA). The confirmation of multilayer structure was observed by transmission electron microscope (TEM). The wear tracks were revealed by scanning electron microscope (SEM). Mechanical and high-temperature tribological properties were evaluated using a nano-indenter and a high-temperature tribometer, respectively.Grain refinement phenomenon was verified using XRD peak broadening at high angles, indicating inhibition in the column structure and the formation of an amorphous phase. CrMoN/SiNx exhibited higher high-temperature wear resistance for a specific bi-layer period, which was attributed to the multilayer strengthening mechanism. Multilayered structure provided tremendous benefit to COF improvement, which was reduced by 50% of the value of CrMoN. Simultaneously, the toughening effect of the biomimetic structure design improved the wear resistance ability of the coating. Especially, the slight amount of SiNx unpredictably enhanced the wearing properties of the system, which is in consistent with the role of chitin in nacre. Moreover, an optimal bi-layer period was identified, resulting in optimal mechanical properties that were consistent with the high-temperature tribological properties. Furthermore, the wear tracks on the specimens were analyzed through field-emission scanning electron microscopy, which support the wearing behavior alteration. Finally, a CrMoN/SiNx multilayer coating with optimal high-temperature characteristics was demonstrated in this study.

Sr-containing micro/nano-hierarchical textured TiO2 nanotubes on 3D printing titanium

The design of biomimetic structures on the surface of titanium implants is critical to improve cell response and bone integration. In this work, Sr-incorporated micro/nano hierarchical structures coatings were fabricated on 3D printing titanium by acid etching, anodization, and hydrothermal treatment. Various characterizations were used to investigate the morphology, hydrophilicity, corrosion resistance, crystal phase, and chemical composition of coatings. Furthermore, we also investigated their in-vitro mineralization capacity upon soaking in simulated body fluid. The obtained coatings show not only excellent corrosion resistance (−0.32 V), high adhesion strength (10.51 N), and hydrophilicity (7.6°), but also superior apatite induction ability. These results suggest that Sr-containing micro/nano-hierarchical textured coatings exhibit potential applications in orthopedic implant materials.

Structure-behaviour correlations between two genetically closely related snail species.

Species, through their structure and composition, have evolved to respond to environmental constraints. Predator–prey interactions are among environmental pressures that can lead to speciation, but it remains unclear how this pressure can be related to the material structure and performance. Recently, two land snails, Karaftohelix editha and Karaftohelix gainesi, were found to exhibit divergent phenotypes and responses to predation despite sharing the same habitat and most of their genome. Indeed, under attack from a beetle, K. editha snails retract into their shell whereas K. gainesi snails swing their shell. In this paper, we looked at the microstructure, composition, morphology and mechanics of the shells of those two species and discuss potential relationships between material structure and the snail defence behaviour. The results of this study provide additional arguments for the role of predator–prey interactions on speciation, as well as an unusual approach for the design of biomimetic structures adapted to a particular function.

Biomimetic systems and design in the 3D characterization of the complex vascular system of bamboo node based on X-ray microtomography and finite element analysis

Bamboo is a natural composite and one of the most efficient structures in nature because of the relationship of mechanical properties with its microstructural features. This research presents the 3D characterization of the reinforcement bundles of a branching nodal region of bamboo, through high-resolution X-ray microtomography (µCT). µCT was used to characterize a sample regarding the volume, relative density, and porosity of parenchyma and sclerenchyma tissues, and the resulting data were used to estimate their constitutive properties. A nonlinear finite element analysis (FEA) was performed based on a discretized model of the µCT to the limiting compressive load. Secondary bundles presented an interweaved arrangement into the primary vascular elements that distribute axial compressive stresses into new branches. Our findings suggest that the foam-like behavior of the parenchyma, the sclerenchyma thickening above the nodal zone, and the nodal vascular branching are ways for bamboo to protect important tissues from mechanical stress by allocating axial loads. In addition, such mechanism could be applied in the design of biomimetic structures with selective load-bearing capabilities.

Orthogonal Halogen‐Bonding‐Driven 3D Supramolecular Assembly of Right‐Handed Synthetic Helical Peptides

AbstractPeptide‐mediated self‐assembly is a prevalent method for creating highly ordered supramolecular architectures. Herein, we report the first example of orthogonal C−X⋅⋅⋅X−C/C−X⋅⋅⋅π halogen bonding and hydrogen bonding driven crystalline architectures based on synthetic helical peptides bearing hybrids of l‐sulfono‐γ‐AApeptides and natural amino acids. The combination of halogen bonding, intra‐/intermolecular hydrogen bonding, and intermolecular hydrophobic interactions enabled novel 3D supramolecular assembly. The orthogonal halogen bonding in the supramolecular architecture exerts a novel mechanism for the self‐assembly of synthetic peptide foldamers and gives new insights into molecular recognition, supramolecular design, and rational design of biomimetic structures.

Biomimetic, recyclable, highly stretchable and self-healing conductors enabled by dual reversible bonds

Utilization of self-healing chemistry and biomimetic structure design, to develop stretchable conductors that are self-healing and recyclable, is of great interest. Herein, we utilize small molecular (triethanolamine, TEA) instead of common polymer segments as a spacer and cross-linker, which could render the dynamic covalent/noncovalent thermosets with higher density of reversible bonds (H-bonds and disulfide bonds) and more cross-linked points through controlling mole fraction due to more hydroxyl group per molecular weight of TEA. The as-prepared thermosets exhibit excellent thermal stability, shape memory effect, recyclability and healing efficiency at relatively moderate temperature. Then, a series of mechanically and electrically self-healing conductive tendrils composed of self-healing/shape memory polymers and conductive percolation networks are fabricated, which possess enhanced conductivity retention capability under stretching states. Moreover, our designed helical-structured conductors can be not only rehealed but also recycled and reprocessed due to the simultaneous destruction and reestablishment of the reversible bonds. Strikingly, the fabrication process of self-healing conductive tendrils is compatible to the conventional technique of conductors including silk-screen printing and adhesive bonding technique. This biomimetic approach opens a promising pathway to fabricate wearable intelligent devices with versatile functions.

BIOMIMETIC STRUCTURE DESIGN OF DRAGONFLY WING VENATION USING TOPOLOGY OPTIMIZATION METHOD

Scientists have carried out research for various biomimetic applications based on the dragonfly wings because of the superb flying skills and lightsome posture. The wings of dragonflies are mainly composed of veins and membranes, which give rise to the special characteristics of their wings that make dragonflies being supremely versatile, maneuverable fliers. Mimicking the dragonfly wing motion is of great technological interest from application's point of view. However, the major challenge is the biomimetic fabrication to replicate the wing motion due to the very complex nature of the wing venation of dragonfly wings. In this regard, the topology optimization method (TOM) is useful to simplify object's structure while retaining its mechanical properties. In this paper, TOM is employed to simplify and optimize the venation structure of dragonfly (Pantala flavescens Fabricius) wing that is captured by a 3D scanner and numerical reconfiguration. Combined with the material parameters obtained from nanoindentation testing, the quantitative models are established based on a finite element (FE) analysis and discussed in static range. The quantitative models are then compared with the square frame, staggered grid frame and hexagonal frame to examine the potentials of the biomimetic structure design for the fabrication of greenhouse roof.

Biomimetic structure design — a possible approach to change the brittleness of ceramics in nature

Based on the analysis on structure of natural biomaterials, two kinds of ceramic composites with high toughness have been designed and prepared: one is fibrous monolithic Si 3N 4/BN composite imitating bamboos or trees in structure, the other is laminated Si 3N 4/BN composite imitating nacre in structure. Plastic forming methods, including extrusion and roll compaction, respectively, followed by hot-pressed sintering are used to prepare these two materials with particular structures. Both of the two composites have high values of fracture toughness and work of fracture: fracture toughness are 24 MPa m 1/2 and 28 MPa m 1/2, respectively, for fibrous monolithic and laminated Si 3N 4/BN composites, and works of fracture are both more than 4000 J/m 2. The load-displacement curves reveal that these two materials with biomimetic structure exhibit non-brittle feature when applied load to fracture. Through analysis on fractographs of the materials, it is revealed that high toughness comes from the synergistic toughening among multi-level toughening mechanisms in different scales: weak interfaces, whiskers and elongated grains toughening in ceramic matrix cells.