Bionic Design Research Articles

Bionic Adhesion Systems: From Natural Design to Artificial Application

AbstractCreatures in nature perform a variety of activities through adhesion behavior, including moving flexibly and quickly on inclined and vertical walls and even ceilings. Studying the physical and chemical mechanisms underlying their adhesion behaviors can provide effective templates for applications such as climbing robots, grippers, and medical devices. This review summarizes various major types of adhesion that creatures rely on and their morphological structures that enhance adhesion, in addition to discussing their inspiration regarding the design of bionic adhesion systems. First, different adhesion types adopted by creatures in various natural environments are introduced, and the adhesion mechanisms and their theoretical models are summarized. Subsequently, the convergent evolution exhibited in biological adhesion structures is summarized from three perspectives: size limitation, compliance, and fluid transport. The development of the bionic design process wherein researchers imitate the natural biological adhesion process to create artificial adhesives is then presented regarding three mechanisms: chemical bonding adhesives, fiber arrays, and suckers. Fiber arrays are further divided into dry adhesives and wet adhesives. Finally, the shortcomings of the existing bionic adhesion systems and future trends are summarized.

A Problem-solving Bionic Design Methodology for Structural Applications (BREED)

Background:: Nature-inspired designs, which have evolved from proven strategies of nature, have been a constant source of inspiration for designers and engineers to solve real-life problems. Methods:: Current bionic design methods are theoretical and are discordant with the design engineering workflow. A proposed methodology suggests suitable bionic forms for a given design space. This procedure consists of the following stages: bionic representation, relation, emulation, engineering specifications, design verification, optimisation (BREED), and finally, realisation. Results:: This methodology aims to function as a systematic problem-solving approach to retrieve structural inspirations from nature and mimic its form. Conclusion:: The inspiration and validation phases of the bionic structure are represented as a Vmodel. The designer can leverage this framework to develop novel bionic design concepts.

Wireless Battery‐Free Peripheral Nerve Stimulation Conch for Remote Muscle Activation

AbstractPeripheral nerve stimulators have emerged as a crucial instrument in the realm of neurological disease, capable of modulating nerve activity through precisely targeted electrical stimulation to specific sites within the nervous system. Herein, a new wireless battery‐free peripheral nerve stimulation device for remote muscle activation is developed. The device with conch‐inspired bionic design can be wirelessly powered and controlled by a mobile phone playing audio via the piezoelectric effect. The device consists of two parts: a conch‐like signal‐intensifying piezoelectric resonator for converting acoustic wave into electrostimulation signal; and a pedestal with stimulation electrodes for transmitting the electrostimulation signal to a peripheral nerve. For remote nerve intervention, a programmed audio tone from one mobile phone can be tele‐transmitted from other phones according to the desired stimulation protocols. In‐vivo experiments in stimulating the sciatic nerve in mice showed that the device can activate muscles (e.g., 1 Hz 920 mV for 26 degree of leg movement), and the neuron‐muscle interaction has been confirmed by electromyogram (EMG). The wireless peripheral nerve stimulation conch achieves feasible remote muscle activation without batteries, and can extend the scope of self‐powered techniques for telemedicine and limb/trunk rehabilitation.

“Bobbit Worm”‐Inspired Soft Adaptive Grasper with Self‐Generated Triboelectric Force Sensor

AbstractSoft actuators can realize delicate adaptive grasping of fragile and irregularly shaped objects, which are essential in biological and engineering systems. Yet, critical concerns in the frontier soft graspers are insufficient grasping ability and functional limitations. Here, we propose a Bobbit worm‐inspired multimodal‐sensing adaptive soft grasper (MSASG) enabled by harnessing the Miura‐origami skeleton integrated with self‐generated triboelectric force sensors (TFSs). The Miura‐origami skeleton endows the soft grasper a high grasping force while provides an energy‐efficient way to passively embrace an object without extra energy input. A multimodal TFSs with tactile sensing (TFS‐1) and pressure‐feedback (TFS‐2) functions is constructed by directly packaging a pyramid‐pattern elastic film on the Miura‐origami skeleton. The MSASG implement fast grasping or releasing action by evaluating pressures of various approaching prey, including hermit crabs, crickets, and beetle, etc. And its sensitivity greater than 0.18 V mN−1. In particular, the grasping performances and triboelectric sensing capacity can be optimized by modulating topological parameters (crease length, and surface film thickness, etc.), using a combination of theoretical modeling, finite element simulations, and experiments. The bionic design of soft graspers broadens the future applications for versatile human‐robot‐environment interaction scenarios, such as adaptive robots, reconfigurable architectures, medical devices, and deep‐sea explorations.

Bioinspired hybrid helical structure in lobster Homarus Americanus: Enhancing penetration resistance and protective performance

The high impact and penetration resistance of the cuticle in the lobster Homarus americanus can be attributed to its unique twisted plywood structure. Hybridization of two helical structures was observed in the exoskeleton, with different pitch angles and ply thickness of the exocuticle and endocuticle within the exoskeleton. Given the survival challenges posed by the natural environment, it is worthwhile to study why it evolved into a hybrid helical rather than a uniform helical structure. In light of this, we have proposed an innovative bionic hybrid helical structure design strategy that goes beyond simply reducing the pitch angle. In this paper, we replicated complex biological microstructures by introducing two types of pitch angles and ply thicknesses for regional configurations. Quasi Static Indentation (QSI) full-penetration experiments were conducted. Experimental results revealed that the exocuticle with a large pitch angle and small ply thickness possesses a higher knee load under the penetration test, which provides a higher initial damage threshold. On the other hand, the endocuticle with a small pitch angle and large ply thickness induces higher damage dissipation, which provides superior protective performance. These research findings demonstrate that ply hybridization can be a promising method for microstructure design to improve the penetration resistance of thin laminates and serve as a reference for developing more refined gradient helical structure designs.

Bionic Design and Optimization of the Wear-Resistant Structure of Piston Rings in Internal Combustion Engines

Internal combustion engines, during their operation, subject the piston to high-temperature and high-pressure conditions, requiring it to endure intense, continuous reciprocating motion. This strenuous process leads to significant wear and tear. Among the engine’s crucial components, the piston ring plays a pivotal role but is particularly susceptible to wear. Therefore, extensive research has been devoted to investigating the wear of piston rings, a critical sealing component within internal combustion engines. To address the high cost of existing coating methods, which hinders widespread application, we propose a bionic design approach inspired by groove structures observed on earthworm bodies, aimed at enhancing the wear resistance of piston rings. Bionic piston rings featuring optimally designed groove structures inspired by the earthworm’s anatomy were designed. These rings exhibited varying groove depths (1 mm, 2 mm, and 3 mm), groove widths (0.1 mm, 0.3 mm, and 0.5 mm), and groove spacings (0.1 mm, 0.2 mm, and 0.3 mm). We conducted thermal–structural coupling analyses on both standard piston rings and these bionic counterparts. The results revealed that the maximum stress was concentrated at the first piston ring, precisely at the opposing region of the end gap. Thus, the initial piston ring endured the primary frictional losses. Moreover, a comparison of stress levels between bionic rings and the standard ring revealed that the bionic groove structure substantially reduced stress and minimized stress concentration, thus enhancing wear resistance. Groove width had the most notable influence on wear performance, followed by groove depth and groove spacing. Optimal wear resistance was achieved when the groove depth was 3 mm, groove width was 0.1 mm, and groove spacing was 0.1 mm. Subsequently, we constructed a piston ring friction test bench to validate the wear resistance of the most effective piston ring. The results indicated that the wear resistance of the bionic piston ring exceeded that of the standard piston ring by up to 19.627%. Therefore, incorporating a bionic groove structure within the piston ring can effectively reduce surface friction and enhance wear resistance. This, in turn, can enhance the operational lifespan of internal combustion engines under favorable working conditions.

Light-powered self-oscillation of a liquid crystal elastomer bow

The self-oscillating system is capable of harvesting energy directly from a steady external environment to maintain its own continuous motion, without the need for an additional controller. It has potential application value in the fields such as micromachines, soft robotics and sensors. Currently, existing self-oscillating systems are relatively complex and difficult to fabricate and control, which limits their practical applications. In this paper, we present a novel light-powered self-oscillating liquid crystal elastomer (LCE) bow, composed of one LCE fiber, two cantilever beams and two masses, that can self-oscillate continuously and periodically under steady illumination. Considering the well-established dynamic LCE model and beam theory, we formulate the governing equation of the self-oscillating LCE bow and theoretically investigate its dynamics. Numerical calculations predict that the LCE bow always develops into one of two motion regimes: either static or self-oscillation. The self-oscillation is maintained by the LCE fiber which absorbs light energy to compensate for the damping dissipation. The control strategies and design principles for amplitude, frequency and equilibrium position of the self-oscillation are also investigated in details. The suggested LCE bow offers potential advantages in terms of simple structure, customizable size, flexible regulation and easy assembly, and these findings are expected to provide insights for the design and utilization of self-oscillating LCE bows in autonomous robots, energy harvesters, sensors and bionic design.

Study on lubrication performance of engine piston skirt with bionic design

As the main friction pair of engine, the friction loss of piston-cylinder liner assembly in the working process has become the main reason of engine friction power consumption. Many species in the biological world have formed non-smooth forms of resistance reduction after thousands of years of survival and evolution. Many people have applied this non-smooth shape of drag reduction on organisms to the surface of friction pairs in construction machinery. Based on LX108 engine, the wear and erosion resistance of Scapharca subcrenata surface is applied to the piston skirt, which is the main friction pair in the engine. Nine test schemes were designed according to orthogonal test. This design selects three factors, namely, groove distribution type, groove depth and width, groove spacing, and each factor includes three levels. The macroscopic fluid lubrication state of the whole piston skirt with bionic shape is studied. Through the change of oil film thickness caused by thermal-mechanical coupling deformation of skirt, combined with the average Reynolds equation, the hydrodynamic pressure of lubricating oil, shear stress, and skirt friction force are obtained to verify the contribution of bionic shape to piston drag reduction, wear reduction, wetting increase, and friction power consumption. The simulation and test results show that the lubrication of all parts of the bionic groove piston skirt is better than that of the standard piston; When the depth and width of groove is 0.8 mm and the spacing is 10°, the thicker the oil film thickness of skirt is; The bionic piston whose oil film bearing area is 74%–87% of the standard piston has the smallest normal pressure and friction; When the upper end of the skirt is arranged with groove shape and the lower end is arranged with narrow groove shape between wide grooves, the lubrication effect is better.

Cavitation flow and noise reduction design of bionic hydrofoil based on orthogonal optimization

Hydrofoils hold considerable academic and practical significance in the realms of marine science, energy generation, and water-based engineering. They offer enhanced speed, efficiency, stability, and maneuverability. Bionic structures have emerged as potent tools for reducing energy losses and noise in hydraulic machinery, making bionic hydrofoils a hotbed of research activity. While prominent scholars have historically directed their bionic investigations toward airfoils, operating in compressible flow fields, recent research has shifted its focus to hydrofoils. The hydrofoil's operating environment is characterized by water instead of air, featuring incompressible flow, relatively low Reynolds and Mach numbers, and notably, cavitating flow. This study presents the bionic optimization design of a wavy leading edge for the hydrofoil, employing orthogonal experimental theory. The authors establish rankings for structural parameters of bionic hydrofoils and identify optimal parameter combinations, offering an optimization strategy for selecting bionic configurations. Subsequently, the authors conduct a numerical investigation into cavitating flow, integrating the FW–H (Ffowcs Williams and Hawkings) equation for the analysis of cavitation-induced noise. Notably, this research delves into the underlying mechanisms responsible for the efficacy of bionic structures in enhancing hydrodynamic performance, particularly in the reduction of cavitation-induced noise within cavitating flow, an area scarcely explored in formal publications. The results reveal that the amplitude of the wavy leading edge exerts the most significant influence on the lift-to-drag ratio, as well as the far-field sound pressure level, followed closely by the wavelength. When compared with a baseline hydrofoil, the optimized bionic hydrofoil demonstrates a substantial 45% reduction in maximum cavity volume and a noteworthy 1.3 dB reduction in far-field noise sound pressure level. These findings underscore the capacity of the optimized bionic hydrofoil to effectively suppress cavitation and its associated noise. The established optimization strategy, focused on cavitation suppression and noise reduction, lays a robust foundation for subsequent studies involving complex working conditions.

Integrated innovation of smart materials and product design from the perspective of design intelligence

Materials are the physical basis and carrier of product design, and the selection of materials is an important part of product design. With the continuous exploration of materials, smart materials have become a hot topic in science and technology innovation. This study uses the winning entries of industrial design awards in the past five years as the data source, and 54 design entries using smart materials for innovative design were obtained after retrieval. The current status of the application of smart materials in product design has been summarised through classification analysis, case analysis and comparative analysis. It is found that the integrated innovation of smart materials and product design is still relatively simple. There is still a lot of space for the development of the application of smart materials in product design. In terms of the existing ways of integration of smart materials and product design, this study proposes that the future integration of product design and smart materials can be innovated from biology, ecology, sensing and computing perspectives through methods such as bionic design, sustainable design, personalised design and parametric design. This study provides a reference for the application of smart materials and new creative expressions in future product design and proposes a new trend for the integration of smart materials and product design in the future.

Design and optimization of bionic Nautilus volute for a hydrodynamic retarder

To reduce the energy loss of volute and improve the emergency braking performance of hydrodynamic retarder under design condition, a bionic volute optimization design method is proposed based on the Nautilus shell. First, the accuracy of the numerical method is verified by grid convergence analysis and experiments. Thereafter, the bionic parametric expression is performed based on the cross-section shape of the Nautilus shell. Subsequently, sample points are created using the Optimal Latin Hypercube sampling method and numerically simulated. Radial basis function neural network and multi-objective genetic algorithm are used for optimization. Finally, the flow field inside the volute and the braking performance of the hydrodynamic retarder are compared by numerical calculation and experiment. Results show that the internal flow field of the bionic volute is more uniform, the energy loss is reduced by 78.95%, and the oil flow speed is increased by 40.61%. In addition, the stable flow field can be established faster during braking, the peak torque can be increased by 6.15%, and the onset time can be advanced by 6.58%. The analysis of energy characteristics shows that the improved performance of the bionic volute can be attributed to its improved internal oil flow conditions, thus reducing the energy loss.

The second clinical study investigating the surgical method for the kineticomyographic control implementation of the bionic hand

In 2018, during our first clinical study on the kineticomyographic (KMG)-controlled bionic hand, we implanted three magnetic tags inside the musculotendinous junction of three paired extensor-flexor transferred tendons. However, the post-operative tissue adhesions affected the independent movements of the implanted tags and consequently the distinct patterns of the obtained signals. To overcome this issue, we modified our surgical procedure from a one-stage tendon transfer to a two-stage. During the first surgery, we created three tunnels using silicon rods for the smooth tendon gliding. In the second stage, we transferred the same three pairs of the forearm agonist–antagonist tendons through the tunnels and implanted the magnetic tags inside the musculotendinous junction. Compared to our prior clinical investigation, fluoroscopy and ultrasound evaluations revealed that the surgical modification in the current study yielded more pronounced independent movements in two specific magnetic tags associated with fingers (maximum 5.7 mm in the first trial vs. 28 mm in the recent trial with grasp and release) and thumb (maximum 3.2 mm in the first trial vs. 9 mm in the current trial with thumb flexion–extension). Furthermore, we observed that utilizing the flexor digitorum superficialis (FDS) tendons for the flexor component in finger and thumb tendon transfer resulted in more independent movements of the implanted tags, compared with the flexor digitorum profundus (FDP) in the prior research. This study can help us plan for our future five-channel bionic limb design by identifying the gestures with the most significant independent tag displacement.

An Analysis of Trabecular Bone Structure Based on Principal Stress Trajectory.

To understand the mechanism of Wolff's law, a finite element analysis was performed for a human proximal femur, and the principal stress trajectories of the femur were extracted using the principal stress visualization method. The mechanism of Wolff's law was evaluated theoretically based on the distribution of the principal stress trajectories. Due to the dynamics of the loads, there was no one-to-one correspondence between the stress trajectories of the fixed load and the trabeculae in the cancellous architecture of the real bone. The trabeculae in the cancellous bone were influenced by the magnitude of the principal stress trajectory. Equivalent principal stress trajectories suitable for different load changes were proposed through the change in load cycle and compared with the anatomical structure of the femur. In addition, the three-dimensional distribution of the femoral principal stress trajectory was established, and the adaptability potential of each load was discussed. The principal stress visualization method could also be applied to bionic structure design.

Intuitive movement-based prosthesis control enables arm amputees to reach naturally in virtual reality.

Impressive progress is being made in bionic limbs design and control. Yet, controlling the numerous joints of a prosthetic arm necessary to place the hand at a correct position and orientation to grasp objects remains challenging. Here, we designed an intuitive, movement-based prosthesis control that leverages natural arm coordination to predict distal joints missing in people with transhumeral limb loss based on proximal residual limb motion and knowledge of the movement goal. This control was validated on 29 participants, including seven with above-elbow limb loss, who picked and placed bottles in a wide range of locations in virtual reality, with median success rates over 99% and movement times identical to those of natural movements. This control also enabled 15 participants, including three with limb differences, to reach and grasp real objects with a robotic arm operated according to the same principle. Remarkably, this was achieved without any prior training, indicating that this control is intuitive and instantaneously usable. It could be used for phantom limb pain management in virtual reality, or to augment the reaching capabilities of invasive neural interfaces usually more focused on hand and grasp control.

Intuitive movement-based prosthesis control enables arm amputees to reach naturally in virtual reality

Impressive progress is being made in bionic limbs design and control. Yet, controlling the numerous joints of a prosthetic arm necessary to place the hand at a correct position and orientation to grasp objects remains challenging. Here, we designed an intuitive, movement-based prosthesis control that leverages natural arm coordination to predict distal joints missing in people with transhumeral limb loss based on proximal residual limb motion and knowledge of the movement goal. This control was validated on 29 participants, including seven with above-elbow limb loss, who picked and placed bottles in a wide range of locations in virtual reality, with median success rates over 99% and movement times identical to those of natural movements. This control also enabled 15 participants, including three with limb differences, to reach and grasp real objects with a robotic arm operated according to the same principle. Remarkably, this was achieved without any prior training, indicating that this control is intuitive and instantaneously usable. It could be used for phantom limb pain management in virtual reality, or to augment the reaching capabilities of invasive neural interfaces usually more focused on hand and grasp control.

Research and application of biomimetic modified ceramics and ceramic composites: A review

AbstractCeramic materials are widely used in engineering field because of their good physical and chemical properties. The poor mechanical properties of traditional ceramics seriously limit the development of ceramic materials and have attracted extensive attention since its birth. The development of high toughness, light weight, and functional ceramic materials has long been the pursuit of materials scientists. Since ancient times, nature has been the source of all kinds of human technological ideas, engineering principles, and major inventions. The functional structure of biology provides a good research object for the bionic design and preparation of ceramic materials. Therefore, it is necessary to summarize the functional structures and mechanisms in nature and biomimetic preparation technology. The purpose of this review is to provide guidance for the functionalized biomimetic design and efficient preparation of ceramic materials. Some typical functional examples in nature are introduced in detail, and several representative biomimetic preparation methods are listed. Finally, the performance and application status of biomimetic ceramics are summarized, and the future development direction of biomimetic ceramic materials is prospected.

Composite nanofillers with a locust-like cushioned half-moon structure to improve the impact resistance of polyurethane

Developing a highly impact absorption properties polyurethane elastomer with exceptional strength and toughness is crucial in the realm of polyurethane impact protection. Inspired by the energy dissipation structure of the soft and hard bonding in the hind limb of locusts, the paper fixed the dynamic disulphide bonds commonly found in bioproteins after hydroxy-functionalized on SiO2 by quaternization reaction, and is creatively applied in the field of impact resistance as soft and hard sacrifice micro-regions into the polyurethane. Benefiting from the multi-scale energy dissipation approach formed by the breakage of dynamic disulphide bonds, the stress obstruction by rigid particles, and the strong bonding interface between the composite filler and the matrix, polyurethane composite have demonstrated great efficiency in energy absorption and impact protection. The static compression strength of IPS@SiO2/PUE is 148.8% higher compared to neat PUE. Furthermore, the dynamic impact energy absorption of the composite PUE was increased by 109.36%, nearly twice that of the original polyurethane. This study proposes that this strategic approach has the potential to offer a novel method for material design, which facilitates bionic design of high-impact protective elastomers utilizing different energy dissipation mechanisms.

Quantitative analysis of the morphing wing mechanism of raptors: IMMU-based motion capture system and its application on gestures of a Falco peregrinus

This paper presented a novel tinny motion capture system for measuring bird posture based on inertial and magnetic measurement units that are made up of micromachined gyroscopes, accelerometers, and magnetometers. Multiple quaternion-based extended Kalman filters were implemented to estimate the absolute orientations to achieve high accuracy. Under the guidance of ornithology experts, the extending/contracting motions and flapping cycles were recorded using the developed motion capture system, and the orientation of each bone was also analyzed. The captured flapping gesture of the Falco peregrinus is crucial to the motion database of raptors as well as the bionic design.

Gustation-Inspired Dual-Responsive Hydrogels for Taste Sensing Enabled by Machine Learning.

Human gustatory system recognizes salty/sour or sweet tastants based on their different ionic or nonionic natures using two different signaling pathways. This suggests that evolution has selected this detection dualism favorably. Analogically, this work constructs herein bioinspired stimulus-responsive hydrogels to recognize model salty/sour or sweet tastes based on two different responses, that is, electrical and volumetric responsivities. Different compositions of zwitter-ionic sulfobetainic N-(3-sulfopropyl)-N-(methacryloxyethyl)-N,N-dimethylammonium betaine (DMAPS) and nonionic 2-hydroxyethyl methacrylate (HEMA) are co-polymerized to explore conditions for gelation. The hydrogel responses upon adding model tastant molecules are explored using electrical and visual de-swelling observations. Beyond challenging electrochemical impedance spectroscopy measurements, naive multimeter electrical characterizations are performed, toward facile applicability. Ionic model molecules, for example, sodium chloride and acetic acid, interact electrostatically with DMAPS groups, whereas nonionic molecules, for example,D(-)fructose, interact by hydrogen bonding with HEMA. The model tastants induce complex combinations of electrical and volumetric responses, which are then introduced as inputs for machine learning algorithms. The fidelity of such a trained dual response approach is tested for a more general taste identification. This work envisages that the facile dual electric/volumetric hydrogel responses combined with machine learning proposes a generic bioinspired avenue for future bionic designs of artificial taste recognition, amply needed in applications.

Preparation of Strong and Thermally Conductive, Spider Silk-Inspired, Soybean Protein-Based Adhesive for Thermally Conductive Wood-Based Composites.

The development of formaldehyde-free functional wood composite materials through the preparation of strong and multifunctional soybean protein adhesives to replace formaldehyde-based resins is an important research area. However, ensuring the bonding performance of soybean protein adhesive while simultaneously developing thermally conductive adhesive and its corresponding wood composites is challenging. Taking inspiration from the microphase separation structure of spider silk, boron nitride (BN) and soy protein isolate (SPI) were mixed by ball milling to obtain a BN@SPI matrix and combined with the self-synthesized hyperbranched reactive substrates as amorphous region reinforcer and cross-linker triglycidylamine to prepare strong and thermally conductive soybean protein adhesive with cross-linked microphase separation structure. These findings indicate that mechanical ball milling can be employed to strip BN followed by combination with SPI, resulting in a tight bonded interface connection. Subsequently, the adhesive's dry and wet shear strengths increased by 14.3% and 90.5% to 1.83 and 1.05 MPa, respectively. The resultant adhesive also possesses a good thermal conductivity (0.363 W/mK). Impressively, because hot-pressing helps the resultant adhesive to establish a thermal conduction pathway, the thermal conductivity of the resulting wood-based composite is 10 times higher than that of the SPI adhesive, which shows a thermal conductivity similar to that of ceramic tile and has excellent potential for developing biothermal conductivity materials, geothermal floors, and energy storage materials. Moreover, the adhesive possessed effective flame retardancy (limit oxygen index = 36.5%) and mildew resistance (>50 days). This bionic design represents an efficient technique for developing multifunctional biomass adhesives and composites.