Browse Topic: Biomimetics

Items (54)
To improve stress-distribution uniformity and reduce wear during polishing, a biomimetic flexible polishing tool was developed by incorporating microstructured surface features inspired by the gastropod shell. A biomimetic flexible polishing tool was first geometrically modeled, and then the tool–workpiece contact was analyzed in the elastic polishing regime using Preston’s material removal equation to elucidate stress transmission and contact deformation mechanisms. An Abaqus finite-element model of the elastic tool–workpiece contact was subsequently established to compute tool and workpiece stress fields and contact-area fraction during polishing. The biomimetic tools were fabricated by curing silicone rubber mixed with carbon nanotubes. Polishing validation was performed on a small CNC platform using quartz glass under the parameters α=15°, ap=2mm, and w=30r/s. Results indicate that the biomimetic tool incorporating gastropod-shell microstructures increases the machining contact area by up to 48.60% relative to a conventional tool, and after t=30 min of polishing the surface roughness Ra decreased from 1.019μm to 76nm. These outcomes demonstrate that the biomimetic microstructured flexible tool effectively improves contact stress uniformity and enhances surface- processing accuracy for quartz glass.
Song, JintaoHui, JizhuangGuo, LeiXu, ChenHei, ZhengqiangZhong, TaiyangWang, JiaweiLiu, Jin
Aerodynamicists around the globe are developing mechanisms and structures inspired by nature that enable variable camber morphing (VCM) for aerodynamic surfaces. The implementation of the VCM mechanism in an airplane wing enhances the performance and stability during various flight segments. The present review article is focused mainly on the up-to-date VCM methods in a qualitative as well as quantitative approach that are specific to Aircraft/unmanned aerial vehicle (UAV) wing configurations. Initial literature discussions are confined to the conventional mechanisms that enable VCM in different aircraft configurations and the added aerodynamic advantages such as lift enhancement, drag reduction, boundary layer separation, and flow control. However, those designs need either external shape optimization or internal structural refinements to ensure the factor of safety (FoS). The modern aviation industry is also focused on bioinspired technology because of the adaptive flying capabilities and stall-delay characteristics. Therefore, a review of bioinspired VCM methods that are assessed based on the aerodynamic potentials is sequentially organized in the article. Additionally, considerations are motivated by the application of various compliant structural patterns for VCM in the aircraft industry. The discussion indicates the prospective benefits of morphing toward the future of the Green Aviation industry.
Manjunath, S. V.Jini Raj, R.
As oil and gas exploitation advances into deep seas, risers linking offshore platforms and subsea extraction systems endure long-term complex marine loads. Fatigue damage from Vortex-Induced Vibration (VIV) has become a key factor limiting the safe operation of deep-sea engineering structures. To address this issue, a bionic adaptive rotating fairing, which is adjustable to ocean current directions, was designed. Its main components include buoyancy blocks, a fairing with spiral guide rails on the inner wall, and clamps, which work together to reduce VIV by regulating flow patterns. Numerical simulations of concave and convex fairings showed that under subcritical flow, shifting from a concave to convex cross-section gradually enhances the fairing’s drag and lift reduction effects on risers, with a steady improvement trend. Further comparisons were made between 0.25D convex fairings, 0.35D convex fairings, and bare risers, focusing on drag/lift reduction, vortex shedding frequency, and Strouhal number. Both convex fairings exhibited similar VIV suppression performance to the bare riser, but differed significantly in the percentage reduction of vortex shedding frequency and Strouhal number. Thus, the 0.25D convex fairing was identified as the optimal configuration for VIV suppression among the concave-convex fairings studied.
Zhang, XuSong, GuangmingWang, BaozhongZhao, JinpengChen, Qianshuo
A team of biomedical engineers at Georgia Tech has unveiled a breakthrough in adaptive optics: a bio-mimetic, light-powered soft lens that mimics the human eye’s ability to refocus and adjust to varying light conditions. The research, published in Science Robotics, opens new possibilities for soft robotics, biomedical imaging, and autonomous vision systems.
Researchers have taken inspiration from nature to create a robotic wing that can sense and adapt to changes in water to deliver unparalleled stability.
Performing transportation and exploration tasks on rugged terrain requires both high load-bearing capacity and large suspension stroke. However, the corner module configurations applied to challenging terrain have rarely been explored. This article proposes an integrated framework that combines bionic principles with topology graph–based type synthesis. This framework leads to the creation of a reconfigurable wheel-legged mechanism capable of switching between wheeled locomotion and legged gait modes, which is then implemented as a corner module system. First, inspired by the skeletal–muscular system of the equine leg, a structure–function mapping relationship between the biological system and the mechanical system is established. Second, a multi-loop closed-chain mechanism with biomimetic morphology is represented in the form of graph theory. A configuration atlas of the wheel-legged hybrid mechanism is generated based on the contracted graph and open-loop kinematic chains, and configuration optimization is carried out. Third, on the basis of the optimized configuration, a biomimetic vibration isolation system is integrated. Finally, a corner module system that integrates the reconfigurable wheel-legged mechanism with steering, hub motor is designed, as well as the mechanical structure of modular transporters based on the aforementioned corner modular architecture. The vibration reduction performance and various locomotion modes of the modular transporter are verified by multibody dynamic simulation.
Gao, ZhenhaiZhang, HanyingChen, GuoyingZhang, SuminHan, Zongzhi
The BioMap system represents a groundbreaking approach to collaborative mapping for autonomous vehicles, drawing inspiration from ant colony behavior and swarm intelligence. It implements a fully decentralized protocol where vehicles use virtual pheromone trails to mark areas of uncertainty, change, or importance, enabling efficient map consensus without centralized coordination. Key innovations include novel pheromone-based compression algorithms and bio-inspired consensus mechanisms that allow real-time adaptation to dynamic environments. In a simulated urban scenario (Town10HD), three vehicles achieved balanced load distribution (±1.8% variance) and comprehensive coverage of a 253.2m × 217.9m × 22.4m area. The final fused map contained 311 chunks with 72,785 particles and required only 10.4 MB of storage. Approximately 49.2% of map particles exceeded the pheromone significance threshold, indicating active importance marking, while no high-uncertainty regions remained. These results demonstrate that BioMap enables natural prioritization of critical navigation areas via virtual pheromones, producing high-confidence maps in real time. Overall, the system achieves its objectives of decentralized mapping, efficient communication, and adaptive coverage through bio-inspired mechanisms, marking a significant advance in multi-vehicle SLAM.
Bhargav, Anirudh SSubbarao, Chitrashree
In recent decades, vehicles have evolved from mere means of individual transportation to something much more meaningful. They are no longer mere metal bodies housing combustion engines, but now play a complex role in people’s lives, encompassing emotional, aesthetic, and symbolic aspects. These factors influence consumers’ choice of a model, brand, or version. Based on a literature review of the global automotive sector, including brand literature, scientific articles, and current automotive news, this study aims to analyze the main design and positioning trends adopted by large multinationals in the market. Using the Jeep Renegade as a case study, three design proposals for the model are illustrated and presented as follows: a “facelift,” a “new generation,” and a “concept vehicle.” Next, these design trends are conceptualized, initially illustrating the respective sketches and drafts, which take into account market positioning and the different options for the models presented in each situation described. Furthermore, knowledge that considers biomimetics is used to obtain new solutions and automotive design proposals. Inventor software is used to develop and model the “concept vehicle,” and FlashPrint is used to 3D print the parts, thus enabling the modification of a 1/24 scale Jeep model. Therefore, this study, related to automotive design trends, presents proposals for the conceptual development of automotive models, as well as integrating rapid processes related to perspective drawings and sketches, modeling and robustness features, aerodynamic profile, engineering, and 3D prototyping. Finally, the results allow for conclusions and highlight the different configurations, variables, lines, and new lines that prevail in proposing a different idea and a new design.
Camilo, Pedro GomesGamarra Rosado, Victor OrlandoGuidi, Erick Siqueira
Ioannis Michaloudis must have seemed like an unusual choice of speaker at first. Much of his talk before the scientists, engineers, and entrepreneurs gathered in Dallas for the 2024 summit of the Advanced Research Projects-Energy agency was abstract. He spoke of the sky as the planet’s protective garment, floated the idea of making shade clouds from space junk, and characterized his artwork as “biomimicry of the sky.”
Mathematician hopes to harness principles of dynamic soaring for long-distance flights. University of Cincinnati, Cincinnati, OH How does one of the biggest birds in the world spend so much time in the air? Albatrosses have 11-foot wingspans that carry them across oceans. But it's how they use these wings that makes them world-class flyers, according to a University of Cincinnati aerospace engineering professor.
Enhancing rotor efficiency has been a persistent challenge in the development of micro aerial vehicles (MAV) especially for surveillance and covert operations. This study introduces a new Hybrid Flapping Wing Rotor (Hybrid FWR) configuration inspired by insect's wing flapping mechanics to address the efficiency limitation of traditional rotor designs. Unlike traditional rotary systems that rely solely on rotational motion, the Hybrid FWR combines rotational and flapping motions to significantly enhance lift generation. A comprehensive mathematical model was developed to analyze and predict the optimal aerodynamic performance, demonstrating that the Hybrid FWR configuration achieves a substantial improvement, with a power efficiency increase of up to 2.148-fold compared to conventional micro rotorcraft. Experimental validation was conducted to confirm the theoretical predictions, identifying an optimal hybrid ratio of approximately 0.7, which effectively minimizes aerodynamic resistance during the upstroke phase while maximizing lift during the downstroke. This bio-inspired hybrid approach addresses critical limitations of existing MAV rotors, such as limited operational endurance and range. The findings of this research contribute significantly to the advancement of micro rotorcraft technology, presenting a promising direction for future MAV developments with enhanced flight performance and energy efficiency.
Huang, XunLu, LinghaiWhidborne, James
Shear Thickening Fluid (STF) exhibits tunable stiffness under varying loading velocities, making it an ideal candidate for energy absorption in transportation systems subjected to complex loading conditions, such as crash scenarios. Recent research highlights that integrating STF with conventional structures can significantly enhance overall energy absorption performance. In this study, we developed a novel sandwich plate by combining a newly designed bio-inspired 3D periodic structure with STF, aiming to create an advanced energy absorber. A finite element model of this system was developed to simulate the crush tests. Using this numerical model, we conducted additional impact simulations to investigate the effects of impact velocity on key structural responses, including force-displacement curve, as well as energy absorption. The contributions of both the fluid and solid components were analyzed. Our findings indicate that the integrated structure demonstrates superior performance, with significant potential for application in vehicle crash safety systems.
Zhu, FengDeb, Anindya
University of Freiburg, Freiburg, Germany
Unmanned Underwater Vehicles (UUVs) are used around the world to conduct difficult environmental, remote, oceanic, defense and rescue missions in often unpredictable and harsh conditions. A new study led by Flinders University and French researchers has now used a novel bio-inspired computing artificial intelligence solution to improve the potential of UUVs and other adaptive control systems to operate more reliability in rough seas and other unpredictable conditions.
Soft-bending actuators have garnered significant interest in robotics and biomedical engineering due to their ability to mimic the bending motions of natural organisms. Using either positive or negative pressure, most soft pneumatic actuators for bending actuation have modified their design accordingly. In this study, we propose a novel soft bending actuator that utilizes combined positive and negative pressures to achieve enhanced performance and control. The actuator consists of a flexible elastomeric chamber divided into two compartments: a positive pressure chamber and a negative pressure chamber. Controlled bending motion can be achieved by selectively applying positive and negative pressures to the respective chambers. The combined positive and negative pressure allowed for faster response times and increased flexibility compared to traditional soft actuators. Because of its adaptability, controllability, and improved performance can be used for various jobs that call for careful handling or compliant environmental contact. The actuator's simple design and cost-effective manufacturing process contribute to its practicality and scalability. The modeling and conducting simulations on a soft robotic combined positive and negative pressure actuator also aim to design an adaptive soft-robotic gripper with reduced effort and investigate the up scaling of such grippers to extend their applicability to heavy payload handling and assembly. Once the results from simulations and experiments conducted by models are collaborated, the geometrical parameters are modified to get improved results. The improved model is compared in terms of pressure range, bending angle, versatility, and weight-carrying capacity. Simulation is done on Ansys for real-time results. The parametric study helps in establishing correlations between pressure and deflections to accurately control the motion of soft grippers
Lalson, AbiramiSadique, Anwar
This study focuses on developing and deploying an Unmanned Aquatic Vehicle (UAV) capable of underwater travel. The primary objectives of this project are to detect the presence of dimethyl sulfide and toluene, as well as to identify any potential oil leakage in underwater pipelines. The UAV has a maximum operating depth of 300 m below the water surface. The design of this UAV is derived from the natural design of Rhinaancylostoma, an underwater kind of fish. The maximum operational setting for this mission is fixed at a depth of approximately 300 m beneath the surface of the sea, and the choice of this species is suitable for fulfilling the objectives of this undertaking. This technology will mitigate the risk associated with human interaction in inspection processes and has the potential to encompass various other resources in the future. The initial design data of the UAV is determined using analytical processes and verified formulas. The selection of the airfoil is done by comparing numerous options, such as NACA 0006, NACA 0020, and NACA 0024. The comparison investigation shows that the NACA 0008 has a lower coefficient of drag. ANSYS Workbench tool is utilized for executing computational analysis, encompassing hydrodynamic and hydro-structural simulations. An innovative computational molding technique is utilized as a preprocessing step. Structural examination is conducted in a two-step procedure, utilizing eight different materials. The selected materials for analysis are Boron fiber reinforced polymer (BFRP), AS-Carbon fiber reinforced polymer (CFRP), T-300-CFRP, HMS-CFRP, GY-70-CFRP, Kevlar fiber reinforced polymer, E-Glass fiber reinforced polymer (GFRP), and S-GFRP. The solid model of the UAV is subjected to computational analysis under two distinct loading circumstances. This analysis helps in identifying the most effective materials for future examination of the structure utilizing layer model molding in ANSYS ACP software. Afterwards, hybrid composites are prepared with the imposition of advanced fibers, and so the hydro-structural analyses are computed. The hydrodynamic parameters are calculated, and as a result, the structural performance of UAV is monitored. In the end, the most optimal material is chosen for the developed hydrodynamically efficient UAV's construction, to carry out the application efficiently and reliably.
Veeraperumal Senthil Nathan, Janani PriyadharshiniRajendran, MahendranArumugam, ManikandanRaji, Arul PrakashSakthivel, PradeshMadasamy, Senthil KumarStanislaus Arputharaj, BeenaL, NatrayanRaja, Vijayanandh
The development of neural networks to create artificial intelligence in computers was originally inspired by how biological systems work. These ‘neuromorphic’ networks, however, run on hardware that looks nothing like a biological brain, which limits performance. Now, researchers from Osaka University and Hokkaido University plan to change this by creating neuromorphic ‘wetware.’
Human body models have been used for decades to inform efforts in promoting automobile occupant and pedestrian safety. However, many of these models fail to capture the intricacies of individual variability. Cadaveric subjects typically exceed representative age ranges and hence mechanics. Animal subjects typically require specific setups that stray from that which is representative of human crash scenarios. Computational models can only consider so many practical real-world variables. Artificial surrogates, dummies being popular among them, are very popular for reusability and robust data collection. However, even the biomechanically accurate skeletal surrogates available commercially are limited in that they do not consider human variability and skeletal microstructure local variability. The objective of the work herein is to assess computational methods of metastructural variability mimicry by fabrication material. We implement mimicry approaches focusing on bulk isotropic elasticity and in-house structural optimization approaches focusing on pure anisotropy skeletal microstructure mimicry. This allows us to assess rapid and detailed approaches alike and determine which fabrication materials are ideal under which approach. We found that Fortify DT was ideal for mimicking the phenomena present in the GHBMC M50 L5 model when using a walled Gyroid. For microstructural mimicry, we found there to be a range in acceptable bulk material elastic moduli between 2.98 and 36.6 GPa. Ultimately, these findings have the potential to guide practitioners of skeletal microstructure biomimicry.
Hezrony, Benjamin S.C. F. Lopes, PedroBrown, Philip J.
Butterflies can see more of the world than humans, including more colors and the field oscillation direction, or polarization, of light. This special ability enables them to navigate with precision, forage for food, and communicate with one another. Other species, like the mantis shrimp, can sense an even wider spectrum of light, as well as the circular polarization, or spinning states, of light waves. They use this capability to signal a “love code,” which helps them find and be discovered by mates.
Did you know that pythons initially hold onto their prey with their sharp, backward-curving teeth? Medical researchers have long been aware that these teeth are perfect for grasping soft tissue rather than cutting through it, but no one has yet been able to put this concept into surgical practice.
In the quest to develop lifelike materials to replace and repair human body parts, scientists face a formidable challenge: Real tissues are often both strong and stretchable and vary in shape and size.
Researchers have found a way to bind engineered skin tissue to the complex forms of humanoid robots. This brings with it potential benefits to robotic platforms such as increased mobility, self-healing abilities, embedded sensing capabilities and an increasingly lifelike appearance. Taking inspiration from human skin ligaments, the team, led by Professor Shoji Takeuchi of the University of Tokyo, included special perforations in a robot face, which helped a layer of skin take hold. Their research could be useful in the cosmetics industry and to help train plastic surgeons.
Inspired by a small and slow snail, scientists have developed a robot prototype that may one day scoop up microplastics from the surfaces of oceans, seas, and lakes.
Researchers have developed a biomimetic scaffold that generates electrical signals upon the application of pressure by utilizing the unique osteogenic ability of hydroxyapatite (HAp). HAp is a basic calcium phosphate material found in bones and teeth.
A Computational Design Analysis of Scotch Yoke Flapping Steel StructureSAE-PP-003569/10/2023
The scotch yoke mechanism is a suitable choice for applications that require reciprocating motion, such as in flapping wing structures. This paper presents a computational design analysis of a scotch yoke-driven flapping structure, aiming to mimic bird flight. The scotch yoke mechanism converts rotational motion from a drive rotor into alternating up-and-down linear movement of the wings. The design process involves determining suitable geometrical parameters to achieve flapping motion. Finite element analysis (FEA) is conducted to assess the structural behavior of the flapping structure under operational loads and investigate stress distributions. Additionally, topological optimization is employed to minimize the weight of the structure while maintaining optimal strength and stiffness characteristics within design constraints. The preliminary FEA results reveal high stress concentrations in specific regions of the initial design. Based on these findings, appropriate modifications are made to enhance the strength and fatigue life of the structure in the optimized design. This leads to reductions in maximum deformation, stress, and strain, indicating improved performance. The simulations demonstrate the effectiveness of the scotch yoke design in generating the desired reciprocal flapping motion required for ornithopter flight. Moreover, the ability of the scotch yoke mechanism to convert rotational input into alternating linear wing movement suggests its potential to develop more robust and durable flapping wing designs for real-world unmanned aerial systems. By combining computational design analysis, finite element analysis, and topological optimization, this study provides valuable insights into the design and performance enhancement of scotch yoke-driven flapping structures. The findings contribute to the development of efficient and reliable mechanisms for achieving flapping wing motion in ornithopters, opening up possibilities for advancements in unmanned aerial systems technology.
Rayed, Ashraf
Muscle contraction hardening is not only essential for enhancing strength but also enables rapid reactions in living organisms. Taking inspiration from nature, the team of researchers at Queen Mary’s School of Engineering and Materials Science has successfully created an artificial muscle that seamlessly transitions between soft and hard states while also possessing the remarkable ability to sense forces and deformations.
A team of researchers from the Department of Mechanical Science and Bioengineering at Osaka University have invented a new kind of walking robot that takes advantage of dynamic instability to navigate. By changing the flexibility of the couplings, the robot can be made to turn without the need for complex computational control systems. This work may assist the creation of rescue robots that are able to traverse uneven terrain.
Following nature’s example, Lufthansa Technik and BASF have jointly developed the functional surface film AeroSHARK for commercial aircraft. The film is modeled on the microscopic structure of shark skin and is applied to the aircraft’s outer skin. It directly reduces aircraft drag, cuts kerosene consumption and thus CO2 emissions.
Legged robots are very promising for use in real-world applications, but their operation in narrow spaces is still challenging. One solution for enhancing their environmental adaptability is to design a small-sized biomimetic robot capable of performing multiple motions and carrying payloads. In this case, rats that live in caves have attracted a great amount of attention owing to their unrivaled agility and adaptability. Lots of efforts have been made trying to mimic the morphology or motion characteristics of rats.
This paper describes the extension of a free-vortex wake method in state-variable form originally developed for rotarywing applications to flapping-wing flight. Following a detailed mathematical description, the wake model is implemented for a hovering insect representative of a hawk moth. A periodic solution to the wake model is found at hover using a modified harmonic balance algorithm. Next, linearized harmonic decomposition models are obtained and validated against the nonlinear dynamics using simulations. Order reduction methods are explored to guide the development of linearized wake models that provide increased runtime performance compared to the nonlinear and linearized harmonic decomposition wake models while guaranteeing satisfactory prediction of the periodic response of the wake.
Saetti, UmbertoHorn, Joseph
Inspired by the sticky substance that barnacles use to cling to rocks, engineers have designed a strong, biocompatible glue that can seal injured tissues and stop bleeding. The new paste can adhere to surfaces even when they are covered with blood and can form a tight seal within about 15 seconds of application.
Mission-Adaptive Rotor Blade Part I: Mission-Driven Biomimetic Design and Optimization.
Davis, AllenHartl, DarrenLazzara, David
Operationally Adaptive Rotor Blade Part II: Fabrication, Control, and Test of a Biomimetic Design.
Bass, MichaelAllen-Prince, MyrielleMabe, JamesDavis, Allen
ABSTRACT
Saetti, UmbertoRogers,  Jonathan
Researchers have developed a technique that programs 2D materials to transform into complex 3D shapes. Programming thin sheets, or 2D materials, to morph into 3D shapes can enable new technologies for soft robotics, deployable systems, and biomimetic manufacturing, which produces synthetic products that mimic biological processes. The 2D material programming technique allows the team to print 2D materials encoded with spatially controlled in-plane growth or contraction that can transform to programmed 3D structures.
Newly developed computational approaches aid in the design of composites that exhibit remarkable abilities to both sense external cues and adapt to these cues in controllable, ‘programmable’ ways. Air Force Research Laboratory, Arlington, Virginia Biological systems have developed structural motifs that allow these systems to resist mechanical deformation. On the molecular scale, biological catch bonds play a vital role in this functionality since these bonds effectively become stronger under deformation. Inserted into hybrid materials, biomimetic catch bonds could lead to composites that exhibit improved mechanical properties in response to an applied force. Computer simulations were used to investigate the mechanical properties of a network of polymer-grafted nanoparticles (PGNs) that are interlinked by labile “catch” bonds. In contrast to conventional “slip” bonds, the lifetime of catch bonds can potentially increase with the application of force (i.e., the rate of rupture can decrease). Subjecting the PGN networks to a tensile deformation (Figure 1), it was found that the networks encompassing catch bonds exhibit greater ductility and toughness than the networks interconnected by slip bonds. Moreover, when the applied tensile force is released, the catch bond networks exhibit lower hysteresis and faster relaxation of residual strain than the slip bond networks. The effects of the catch bonds on the mechanical behavior are attributed to transitions between two conformational states, which differ in their sensitivity to force. These findings provide guidelines for creating nanocomposite networks that are highly resistant to mechanical deformation and show rapid strain recovery.
This paper discusses an endeavor to experimentally identify the flight dynamics of the AVFL Hummingbird, and quantify its maneuverability and gust tolerance using a control theoretic framework. The AVFL hummingbird is a 62gram, truly biomimetic robotic hummingbird developed to understand and characterize hummingbird flight. It has a pair of biologically inspired, aeroelastically tailored wings flapping at 20Hz, and is fully hover capable. Additionally, like its biological counterpart, it utilizes wing kinematic modulation techniques for control and stability. The vehicle states were measured during targeted flight tests from which a linearized, state-space model was derived. The model contained damping aerodynamic coefficients, decoupled longitudinal, lateral and directional dynamics, as well as large control coefficients. The control theoretic framework, which quantifies the maximum controllable states of the system under unit inputs, was utilized to calculate the maximum gusts tolerable by the control system. The results showed exceptional gust tolerant capabilities. The maximum gusts tolerable were (1) longitudinal gust: 21.2 ft/s (6.4 m/s); (2) lateral gust: 17.7 ft/s (5.4 m/s); (3) lateral rotational gust: 149.8 rad/s; and (4) longitudinal rotational gust: 20.5 rad/s. These are much greater than comparable rotary-wing based systems. This study represents the first time the maneuverability and gust tolerance of a hummingbird-like system has been experimentally characterized, and has shown quantitatively the exceptional flight capabilities offered by biomimetic design and control.
Coleman, DavidBenedict, Moble
NOx pollution from diesel engines has been stated as causing over 10 000 pre-mature deaths annually and predictions are showing that this level will increase [1]. In order to decrease this growing global problem, exhaust after-treatment systems for diesel engines have to be improved, this is especially so for vehicles carrying freight as their use of diesel engines is expected to carry on into the future [2]. The most common way to reduce diesel engine NOx out emissions is to use SCR. SCR operates by injecting aqueous Urea solution, 32.5% by volume (AUS-32), that evaporates prior the catalytic surface of the SCR-catalyst. Due to a catalytic reaction within the catalyst, NOx is converted nominally into Nitrogen and Water. Currently, the evaporative process is enhanced by aggressive mixer plates and long flow paths. The mixer plates create extra exhaust back pressure and cool the exhaust gases, which decreases engine and catalyst efficiency, resulting in overall poor NOx conversion (<40%) and higher CO2 production under real life drive cycle conditions. To achieve future emission legislation targets, SCR efficiency has to be improved, especially under low catalyst temperature conditions. It should also be noted that Ammonia slip has to be avoided as it is now legislated against [3]. In this study a novel biomimetic effervescent aqueous urea injector, its design inspired by the natural spray phenomenon of the Bombardier Beetle, is used to compare against a market-leading aqueous urea doser in comparable exhaust conditions with and without aggressive mixer plates being installed. The novel biomimetic effervescent injector operates by increasing the temperature of the Urea solution inside a constant volume chamber to its saturated vapour pressure. At the required time of injection an electromagnetically controlled outlet valve opens exposing the now superheated fluid to lower pressure conditions, this results in a hot, effervescent spray being ejected which rapidly breaks up into very fine droplets (<20um) projected at high velocity (60m/s) into the exhaust stream targeted at the face of the SCR catalyst. The novel biomimetic effervescent injector shows great potential with a significant higher NOx conversion rate and lower ammonia slip compared to the market-leading doser on a heavy-duty engine.
Larsson, PeterRavenhill, PaulTunestal, Per
This paper describes the development of a biomimetic robotic hummingbird that utilizes biologically inspired wing kinematic modulation strategies for active stability and control. By tilting the flapping planes, varying the relative wing flapping amplitude, and shifting the mean position of the flapping stroke, the robotic hummingbird is able to modulate the magnitude, direction, and location of the lift vector of each of the wings in the same way that hummingbirds do to maneuver and stabilize themselves. In addition to the control strategies, biologically inspired, flexible, aeroelastically tailored wings were developed for use on the vehicle. Flight tests were conducted in which the vehicle was flown in a controlled hover using combinations of control techniques to quantify the effectiveness of each in stabilizing the vehicle. In the present study, emphasis was placed on pitch control, where two different control strategies were investigated, which were (1) pure tilting of the stroke plane, and (2) stroke mean shifting. Based on the flight experiments, a combination of 90% mean shifting and 10% stroke tilting proved to be significantly more effective than pure stroke plane tilting with almost 40% decrease in drift and attitude oscillations. This is the first ever study where the exact kinematic control strategies used by real hummingbirds and two-winged insects are implemented on a robotic flyer and investigated through free-flight testing.
Coleman, DavidBenedict, Moble
NASA's Langley Research Center has developed a method and apparatus to be used for cell culture that combines the effects of microgravity and low-dose radiation. The technology has been developed to simulate the effects of microgravity and chronic radiation exposure to cell culture experiments conducted on the International Space Station (ISS).
Yearly 3.3 million premature deaths occur worldwide due to air pollution and NOx pollution counts for nearly one seventh of those [1]. This makes exhaust after-treatment a very important research and has caused the permitted emission levels for NOx to decrease to very low levels, for EURO 6 only 0.4 g/kWh. Recently new legislation on ammonia slip with a limit of 10 ppm NH3 has been added [2], which makes the SCR-technology more challenging. This technology injects small droplets of an aqueous Urea solution into the stream of exhaust gases and through a catalytic reaction within the SCR-catalyst, NOx is converted into Nitrogen and Water. To enable the catalytic reaction the water content in the Urea solution needs to be evaporated and the ammonia molecules need to have sufficient time to mix with the gases prior to the catalyst. The μMist® platform technology, inspired by nature, uses heat in order to increase the fluid temperature above the required saturation temperature within its constant volume chamber. When the outlet valve is opened the liquid breaks up into small droplets which eject and mix with the gases. This paper presents an investigation on how these heated droplets with SMD around 20μm affect the catalytic conversion and achieve high conversion whilst the ammonia slip is kept to a minimum for a few different mass flows. Injected pre-heated small droplets shows over 95 % catalytic conversion of NOx at exhaust temperatures around 200°C. During continuous operation at catalyst temperatures around 350°C - 370°C several test points reaching from 0.7 kg/h to 1.1 kg/h of AdBlue mass flow, achieved EURO VI legislation at the selected experimental conditions, not included in the WHSC (World Harmonized Steady-State Cycle), for both NOx and ammonia with higher than 98 % conversion efficiency.
Larsson, PeterLennard, WillDahlstrom, JessicaAndersson, OivindTunestal, Per
Increased research is being driven by the automotive industry facing challenges, requiring to comply with both current and future emissions legislation, and to lower the fuel consumption. The reason for this legislation is to restrict the harmful pollution which every year causes 3.3 million premature deaths worldwide [1]. One factor that causes this pollution is NOx emissions. NOx emission legislation has been reduced from 8 g/kWh (Euro I) down to 0.4 g/kWh (Euro VI) and recently new legislation for ammonia slip which increase the challenge of exhaust aftertreatment with a SCR system. In order to achieve a good NOx conversion together with a low slip of ammonia, small droplets of Urea solution needs to be injected which can be rapidly evaporated and mixed into the flow of exhaust gases. In most of today's solutions this process is enhanced with flow restricting mixers or longer path lengths but if these can be removed and shortened the flow losses can be reduced, leading to higher efficiency and lower fuel consumption as well as a more compact exhaust system. The μMist® injector, inspired by nature, takes the concept from the Bombardier beetle which induces flash-boiling in its effective defence mechanism by spraying a plume of hot poisonous fine droplets with great accuracy towards an attacker [3]. By heating up the fluid in a constant volume chamber above the saturation temperature and induce flash evaporation by opening the nozzle, the liquid breaks up into fine droplets which flow out into the target environment. This paper presents a study comparing the different effects of spray behaviour at different ratios between the saturation pressure and the target pressure. In this study the target pressure is atmospheric. The aim for the study is to gain a better understanding of the droplet sizes and the injector flow rates for different pressures and also present a limited benchmarking study of current market leading AdBlue injectors. Current testing has shown that this novel injector has the ability to produce 33% smaller droplets in SMD and 87% reduction in DV50.
Larsson, PeterLennard, WillAndersson, OivindTunestal, Per
While the Japanese art of origami has been “a rich source of inspiration” for scientists working to construct such 3D forms, the limitation to simple shapes has held up development of new applications in areas such as biomimetic systems, soft robotics and mechanical meta-materials, especially for structures on small length scales where traditional manufacturing processes fail. Now, however, a team led by polymer scientist Ryan Hayward has developed an approach that could open the door to a new wave of discoveries.
The Swedish Biomimetics 3000's μMist® platform technology has been used to develop a radically new injection system. This prototype system, developed and characterized with support from Lotus, as part of Swedish Biomimetics 3000®'s V₂IO innovation accelerating model, delivers improved combustion efficiency through achieving exceptionally small droplets, at fuel rail pressures far less than conventional GDI systems and as low as PFI systems. The system gives the opportunity to prepare and deliver all of the fuel load for the engine while the intake valves are open and after the exhaust valves have closed, thereby offering the potential to use advanced charge scavenging techniques in PFI engines which have hitherto been restricted to direct-injection engines, and at a lower system cost than a GDI injection system. The work to date on a prototype injector concentrated on imaging of the fuel spray and combustion in a high-speed optical engine, and emissions and fuel consumption in a functionally identical single-cylinder thermodynamic engine. The performance and emissions measurements included PM, CO and THC emissions combined with IMEP, COV of IMEP and ISFC. The results confirmed performance superior to PFI, and even exceeded some typical GDI characteristics.
Beheshti, N.Walker, R. G.Larsson, L.-U.Copestake, A.Patel, R.Pitcher, G.Turner, J. W. G.Card, C.Wigley, G.McIntosh, A. C.
ABSTRACT Although bio-inspired legged robots have advantageous mobility, they can be very inefficient. Their intrinsic walking mobility is sometimes outweighed by the inefficiency of their drive-train. Some of these inefficiencies are due to collision losses, but they are also due to suboptimal powering schemes. This paper addresses the powering schemes and seeks to clearly delineate an optimal solution to powering the walking motion of a two-legged or biped walker. We examine a simplified model of locomotion called the “rocket car” to extract the meaningful parameters that affect time and energy cost. Using Pontryagin’s Maximum Principle, we dissect the cost function, the state equation, co-state equation, and control input constraints to describe the optimal control. The result of the paper shows a “bang-off” control, and we describe the “coasting line” between these extremes. It is not possible to find a complete closed-form solution for the problem, and numerical methods, such as dynamic programming must be used for future simulation and visualization of the results.
Muench, PaulCheok, Ka C
Natural and Environmentally Responsive Building Envelopes2007-01-30567/9/2007
In a context of global warming and our needs to reduce CO2 emissions, building envelopes will play an important role. A new imperative has been put forth to architects and engineers to develop innovative materials, components and systems, in order to make building envelopes adaptive and responsive to variable and extreme climate conditions. Envelopes serve multiple functions, from shielding the interior environment to collecting, storing and generating energy. Perhaps a more recent concern of terrestrial habitats is permeability and leakages within the building envelope. Such air tight and concealed envelopes with zero particle exchange are a necessity and already exist in regard to space capsules and habitats. This paper attempts to acknowledge existing and visionary envelope concepts and their functioning in conjunction with maintaining a favourable interior environment. It introduces several criteria and requirements of advanced façades along with interior pressurization control. Furthermore, the paper also takes a closer look at the principles of ‘biomimicry’ of natural systems combined with the most up-to-date building materials and construction technologies, trying to integrate the notions of adaptation - where the capacity to survive depends on the ability to adjust to the environment - within the concept of technological evolution and innovation. An ‘adaptive’ attitude in the way in which we conceive our built structures provides a conceptual basis for the advanced building design of our future, as well as one concerned about the efficient management of the available resources. Built environments of the future (in extreme climates or not) will need to respond to Renewable, Adaptive, Recyclable and Environmental (R.A.R.E.) concepts in order to co-exist in a sustainable way with their surroundings.
Luther, Mark B.Altomonte, Sergio
An advanced design methodology is developed for innovative composite structure concepts which can be used in the Army's future ground vehicle systems to protect vehicle and occupants against various explosives. The multi-level and multi-scenario blast simulation and design system integrates three major technologies: a newly developed landmine-soil-composite interaction model; an advanced design methodology, called Function-Oriented Material Design (FOMD); and a novel patent-pending composite material concept, called BTR (Biomimetic Tendon-Reinforced) material. Example results include numerical simulation of a BTR composite under a blast event. The developed blast simulation and design system will enable the prediction, design, and prototyping of blast-protective composite structures for a wide range of damage scenarios in various blast events.
Jiang, DongyingLiu, YuanyuanQi, ChangMa, Zheng-DongRaju, Basavaraju B.Bryzik, Walter
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