BACKGROUND No dynamic technique, such as tendon transfer, has been described for scapular winging due to levator scapulae or rhomboid major and minor palsies resulting from an isolated dorsal scapular nerve injury. Th...BACKGROUND No dynamic technique, such as tendon transfer, has been described for scapular winging due to levator scapulae or rhomboid major and minor palsies resulting from an isolated dorsal scapular nerve injury. Thus, we evaluated how the contralateral trapezius compound osteomuscular flap transfer would work in stabilizing lateral scapular winging, and the case is reported here. A literature review was also conducted, and articles relevant to the case are presented.CASE SUMMARY A 37-year-old male patient who had sustained an isolated dorsal scapular nerve injury underwent reconstructive surgery using the contralateral trapezius compound osteomuscular flap transfer technique to treat scapular winging and the consequent pain, and to restore function from the shoulder impairment. As a result, the involved shoulder showed an improved Constant-Murley score, from19.5% to 81.88%.CONCLUSION Contralateral trapezius osteomuscular flap transfer succeeded in stabilizing scapular winging in this case, improving shoulder function and affording pain relief.展开更多
The core components of an aircraft and the source of its lift are its wings,but lift generation is disrupted by the high temperature and pressure generated on the wing surface when an aircraft gun is fired.Here,to inv...The core components of an aircraft and the source of its lift are its wings,but lift generation is disrupted by the high temperature and pressure generated on the wing surface when an aircraft gun is fired.Here,to investigate how this process influences the aerodynamic parameters of aircraft wings,the k-ωshearstress-transport turbulence model and the nested dynamic grid technique are used to analyze numerically the transient process of the muzzle jet of a 30-mm small-caliber aircraft gun in highaltitude(10 km)flight with an incoming Mach number of Ma=0.8.For comparison,two other models are established,one with no projectile and the other with no wing.The results indicate that when the aircraft gun is fired,the muzzle jet acts on the wing,creating a pressure field thereon.The uneven distribution of high pressure greatly reduces the lift of the aircraft,causing oscillations in its drag and disrupting its dynamic balance,thereby affecting its flight speed and attitude.Meanwhile,the muzzle jet is obstructed by the wing,and its flow field is distorted and deformed,developing upward toward the wing.Because of the influence of the incoming flow,the shockwave front of the projectile changes from a smooth spherical shape to an irregular one,and the motion parameters of the projectile are also greatly affected by oscillations.The present results provide an important theoretical basis for how the guns of fighter aircraft influence the aerodynamic performance of the wings.展开更多
Wing design is a critical factor in the aerodynamic performance of flapping-wing(FW)robots.Inspired by the natural wing structures of insects,bats,and birds,we explored how bio-mimetic wing vein morphologies,combined ...Wing design is a critical factor in the aerodynamic performance of flapping-wing(FW)robots.Inspired by the natural wing structures of insects,bats,and birds,we explored how bio-mimetic wing vein morphologies,combined with a bio-inspired double wing clap-and-fling mechanism,affect thrust generation.This study focused on increasing vertical force and payload capacity.Through systematic experimentation with various vein configurations and structural designs,we developed innovative wings optimized for thrust production.Comprehensive tests were conducted to measure aerodynamic forces,power consumption,and wing kinematics across a range of flapping frequencies.Additionally,wings with different aspect ratios,a key factor in wing design,were fabricated and extensively evaluated.The study also examined the role of bio-inspired vein layouts on wing flexibility,a critical component in improving flight efficiency.Our findings demonstrate that the newly developed wing design led to a 20%increase in thrust,achieving up to 30 g-force(gf).This research sheds light on the clap-and-fling effect and establishes a promising framework for bio-inspired wing design,offering significant improvements in both performance and payload capacity for FW robots.展开更多
Hypersonic morphing vehicle(HMV)can reconfigure aerodynamic geometries in real time,adapting to diverse needs like multi-mission profiles and wide-speed-range flight,spanwise morphing and sweep angle variation are rep...Hypersonic morphing vehicle(HMV)can reconfigure aerodynamic geometries in real time,adapting to diverse needs like multi-mission profiles and wide-speed-range flight,spanwise morphing and sweep angle variation are representative large-scale wing reconfiguration modes.To meet the HMV's need for an increased lift and a lift to drag ratio during hypersonic maneuverability and cruise or reentry equilibrium glide,this paper proposes an innovative single-DOF coupled morphing-wing system.We then systematically analyze its open-loop kinematics and closed-loop connectivity constraints,and the proposed system integrates three functional modules:the preset locking/release mechanism,the coupled morphing-wing mechanism,and the integrated wing locking with active stiffness control mechanism.Experimental validation confirms stable,continuous morphing under simulated aerodynamic loads.The experimental results indicate:(i)SMA actuators exhibit response times ranging from 18 s to 160 s,providing sufficient force output for wing unlocking;(ii)The integrated wing locking with active stiffness control mechanism effectively secures wing positions while eliminating airframe clearance via SMA actuation,improving the first-order natural frequency by more than 17%;(iii)The distributed aerodynamic loading system enables precise multi-stage follow-up loading during morphing,with the coupled morphing wing maintaining stable,continuous operation under 0-3500 N normal loads and 110-140 N axial force.The proposed single-DOF coupled morphing mechanism not only simplifies and improves structural efficiency but also demonstrates superior performance in locking control,stiffness enhancement,and aerodynamic responsiveness.This establishes a foundational framework for the design of future intelligent morphing configurations and the implementation of flight control systems.展开更多
Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or ...Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.展开更多
In bio-inspired flapping-wing flight,lift generation and flexible deformation are intrinsically coupled.Thus,an experimental study is conducted to reveal the fluid-structure interaction mechanism for a flexible plate ...In bio-inspired flapping-wing flight,lift generation and flexible deformation are intrinsically coupled.Thus,an experimental study is conducted to reveal the fluid-structure interaction mechanism for a flexible plate undergoing pitching and plunging motion,and theoretical models are proposed to predict either lift or deformation based on a series of simplifying assumptions.It is indicated that flexible plates can effectively reduce the amplitude of lift and pitching moment coefficients during dynamic stall,with increased flexibility leading to higher load reduction.To investigate the effect of plate flexibility on lift,a definition of effective angle of attack is proposed,incorporating the pitching and plunging motion and chordwise deformation of the flexible plate,which can reduce the hysteresis effect of the lift coefficient during dynamic stall.As a consequence,a theoretical model is developed to predict lift based on observed motion and deformation.On the other hand,another theoretical model is developed to predict flexible-plate deformation utilizing aerodynamic forces,revealing the effect of leading-edge vortex evolution on passive deformation.The influence of kinematic parameters,including the maximum effective angle of attack,reduced frequency,and Strouhal number,on the aerodynamic forces is further studied.Compared with the rigid plate,flexible plates exhibit lower sensitivity of aerodynamic forces to changes in kinematic parameters due to their inherent compliance and resulting deformation.The proposed theoretical models can serve as a reference for aerodynamic and deformation prediction in bio-inspired flexible structures.展开更多
An unsteady numerical simulation is conducted to examine the dynamic runback characteristics of a water film flow driven by a boundary layer airflow over a solid surface pertinent to the dynamic glaze ice accretion pr...An unsteady numerical simulation is conducted to examine the dynamic runback characteristics of a water film flow driven by a boundary layer airflow over a solid surface pertinent to the dynamic glaze ice accretion process over aircraft wing surfaces.The multiphase flow simulation results of the wind-driven water runback(WDWR)flow are compared quantitatively with the experimental results in terms of the time-dependent variations of the water film thickness profiles and evolution of the front contact point of the runback water film flow.The underlying mechanism of the intermittent water runback behavior is elucidated by analyzing the time evolution of the airflow velocity and vorticity fields above the runback water film flow over the solid surface.To the best knowledge of the authors,the work presented here is the first successful attempt to numerically examine the transient runback characteristics of WDWR flows.It serves as an excellent benchmark case for the development of best practices to model the important micro-physical processes responsible for the transient water transport over aircraft wing surfaces.展开更多
Hafnium carbide(HfC)serves as a critical ablation-resistant coating for C/C composites used on the wing leading edges of high-speed vehicles during atmospheric re-entry[1-3].Under the action of high-temperature,oxidiz...Hafnium carbide(HfC)serves as a critical ablation-resistant coating for C/C composites used on the wing leading edges of high-speed vehicles during atmospheric re-entry[1-3].Under the action of high-temperature,oxidizing gas flow,the HfC coating forms a high-melting-point heterogeneous oxide layer,significantly delaying oxidation of the underlying material and preserving the structural integrity of the C/C composites[4].展开更多
This spring, the world again faces the prospect of a bird flu outbreak Hawks, tigers, dogs and cats. These animals are not directly related in the biological chain, but they are all threatened by the same disease-the ...This spring, the world again faces the prospect of a bird flu outbreak Hawks, tigers, dogs and cats. These animals are not directly related in the biological chain, but they are all threatened by the same disease-the H5N1 avian flu virus.展开更多
The design of unmanned aerial vehicles(UAVs)revolves around the careful selection of materials that are both lightweight and robust.Carbon fiber-reinforced polymer(CFRP)emerged as an ideal option for wing construction...The design of unmanned aerial vehicles(UAVs)revolves around the careful selection of materials that are both lightweight and robust.Carbon fiber-reinforced polymer(CFRP)emerged as an ideal option for wing construction,with its mechanical qualities thoroughly investigated.In this study,we developed and optimized a conceptual UAV wing to withstand structural loads by establishing progressive composite stacking sequences,and we conducted a series of experimental characterizations on the resulting material.In the optimization phase,the objective was defined as weight reduction,while the Hashin damage criterion was established as the constraint for the optimization process.The optimization algorithm adaptively monitors regional damage criterion values,implementing necessary adjustments to facilitate the mitigation process in a cost-effective manner.Optimization of the analytical model using Simulia Abaqus~(TM)and a Python-based user-defined sub-routine resulted in a 34.7%reduction in the wing's structural weight after 45 iterative rounds.Then,the custom-developed optimization algorithm was compared with a genetic algorithm optimization.This comparison has demonstrated that,although the genetic algorithm explores numerous possibilities through hybridization,the custom-developed algorithm is more result-oriented and achieves optimization in a reduced number of steps.To validate the structural analysis,test specimens were fabricated from the wing's most critically loaded segment,utilizing the identical stacking sequence employed in the optimization studies.Rigorous mechanical testing revealed unexpectedly high compressive strength,while tensile and bending strengths fell within expected ranges.All observed failure loads remained within the established safety margins,thereby confirming the reliability of the analytical predictions.展开更多
Some of the most interesting areas in aerospace science and technologies are on either higher,faster,and larger systems or lower,slower,and smaller flying capabilities.In this paper,we present our perspectives on the ...Some of the most interesting areas in aerospace science and technologies are on either higher,faster,and larger systems or lower,slower,and smaller flying capabilities.In this paper,we present our perspectives on the aerodynamics related to small,fixed-wing as well as flapping-wing flight vehicles.From an evolutionary viewpoint,flyers have gone through many iterations,adaptations,and optimizations to balance their biological functions,including flight.In the low-Reynolds-number regime,the aerodynamic characteristics around a solid object differ from those observed at the scale of passenger-airplanes.Consequently,the optimal airfoil and wing shapes vary with vehicle size.As vehicle dimensions vary,non-proportional scaling between surface areas and weight shifts the dominance of physical mechanisms,leading to distinct operational parameters and technical requirements.With smaller flight vehicles,structural flexibility as well as anisotropic material properties become more pronounced,which causes qualitative changes in aerodynamics.The flapping motion of the wings,the interactions between wings,the synergistic characteristics of wing and tail,and the development of soft structures for better agility and flight performance are discussed.Low-Reynolds-number aerodynamics require collaborative innovation to optimize shape,motion,and structure of vehicles in accordance with the scaling laws.Together,progress on these fronts is reshaping the design paradigm of air vehicles and other types of robots with shrinking physical dimensions and more versatile capabilities to meet wider ranges of missions.展开更多
This paper investigates the influence of the spanwise-distributed trailing-edge camber morphing on the dynamic stall characteristics of a finite-span wing at Re=2×10^(5).The mathematical model of the spanwise-dis...This paper investigates the influence of the spanwise-distributed trailing-edge camber morphing on the dynamic stall characteristics of a finite-span wing at Re=2×10^(5).The mathematical model of the spanwise-distributed trailing-edge camber morphing is established based on Chebyshev polynomials,and the deformed wing surface is modeled by a spline surface according to the rib's morphing in the chordwise direction.The Computational Fluid Dynamics(CFD)method is adopted to obtain flow-field results and aerodynamic forces.The SST-γmodel is introduced and the overset mesh technique is adopted.The numerical results show that the spanwisedistributed trailing-edge morphing obviously changes the aerodynamic and energy transfer characteristics of the dynamic stall.Especially when the phase difference between the trailing-edge motion and the wing pitch is-π/2,the interaction between the three-dimensional(3-D)Leading-Edge Vortex(LEV)and Trailing-Edge Vortex(TEV)is strengthened,and the work done by the aerodynamic force turns negative.This indicates that the trailing-edge deformation has the potential to suppress the oscillation amplitude of stall flutter.We also found that as the trailing-edge camber morphing varies more complexly along the spanwise direction,the suppression effect decreases accordingly.展开更多
Honeycomb structures of shape memory alloy(SMA)have become one of the most promising materials for flexible skins of morphing aircraft due to their excellent mechanical properties.However,due to the nonlinear material...Honeycomb structures of shape memory alloy(SMA)have become one of the most promising materials for flexible skins of morphing aircraft due to their excellent mechanical properties.However,due to the nonlinear material and geometric large deformation,the SMA honeycomb exhibits significant and complex nonlinearity in the skin and there is a lack of relevant previous research.In this paper,the nonlinear properties of the SMA honeycomb structure with arbitrary geometry are investigated for the first time for large deformation flexible skin applications by theoretical and experimental analysis.Firstly,a novel theoretical model of SMA honeycomb structure considering both material and geometric nonlinearity is proposed,and the corresponding calculation method of nonlinear governing equations is given based upon the shooting method and Runge–Kutta method.Then,the tensile behaviors of four kinds of SMA honeycomb structures,i.e.,U-type,V-type,cosine-type,and trapezoid-type,are analyzed and predicted by the proposed theoretical model and compared with the finite element analysis(FEA)results.Moreover,the tensile experiments were carried out by stretching U-type and V-type honeycomb structures to a global strain of 60%and 40%,respectively,to perform large deformation analysis and verify the theoretical model.Finally,experimental verification and finite element validation show that the curves of the theoretical model results,experimental results,and simulation results are in good agreement,illustrating the generalizability and accuracy of the proposed theoretical model.The theoretical model and experimental investigations in this paper are considered to provide an effective foundation for analyzing and predicting the mechanical behavior of SMA honeycomb flexible skins with large extensional deformations.展开更多
The optimization of wings typically relies on computationally intensive high-fidelity simulations,which restrict the quick exploration of design spaces.To address this problem,this paper introduces a methodology dedic...The optimization of wings typically relies on computationally intensive high-fidelity simulations,which restrict the quick exploration of design spaces.To address this problem,this paper introduces a methodology dedicated to optimizing box wing configurations using low-fidelity data driven machine learning approach.This technique showcases its practicality through the utilization of a tailored low-fidelity machine learning technique,specifically designed for early-stage wing configuration.By employing surrogate model trained on small dataset derived from low-fidelity simulations,our method aims to predict outputs within an acceptable range.This strategy significantly mitigates computational costs and expedites the design exploration process.The methodology's validation relies on its successful application in optimizing the box wing of PARSIFAL,serving as a benchmark,while the primary focus remains on optimizing the newly designed box wing by Bionica.Applying this method to the Bionica configuration led to a notable 14%improvement in overall aerodynamic effciency.Furthermore,all the optimized results obtained from machine learning model undergo rigorous assessments through the high-fidelity RANS analysis for confirmation.This methodology introduces innovative approach that aims to streamline computational processes,potentially reducing the time and resources required compared to traditional optimization methods.展开更多
[Objectives]To explore the effect of selenium(Se)on inhibiting embryo abortion and enhancing seedling cultivation quality of Red sandalwood(Pterocarpus santalinus).[Methods]Based on prior cultivation practices and exp...[Objectives]To explore the effect of selenium(Se)on inhibiting embryo abortion and enhancing seedling cultivation quality of Red sandalwood(Pterocarpus santalinus).[Methods]Based on prior cultivation practices and experimental research,three categories comprising 13 forest soil nutrient management schemes were designed to investigate the synergistic effects of Se,NPK compound fertilizers,and enzyme-microbe fermented organic fertilizers(EFOF)on embryo abortion,winged pod development,and seedling quality of Red sandalwood.[Results]Increasing the Se content in the soil,particularly in the form of selenite/Se(IV),within one month following the harvest of Red sandalwood pods and within two months prior to flower withering,significantly reduced embryo abortion percentage(EAP),and consequently improved seed quality and yield per plant.The effect of Se application was markedly greater than that of the single application of nitrogen(N),phosphorus(P),potassium(K),boron(B)fertilizers,or organic fertilizers.Furthermore,when Se was applied in combination with NPK compound fertilizers and EFOF,these beneficial effects were significantly enhanced.When Se(IV)was applied individually,the EAP decreased by 62.4%,reaching 24.8% at 8 weeks after flower withering(compared to 65.9%in the unmanaged control,UMC).Following winged pod maturation,the percentage of empty winged pods(PEWP)declined by 65.2% to 16.8%(UMC:48.2%),the average individual winged pod weight(IWPW)increased by 69.1%to 0.690 g per fruit(UMC:0.408 g),and the winged pod yield(WPY)rose by 214.8% to 4.03 kg(UMC:1.28 kg).Additionally,the blasted seed percentage(BSP)was reduced by 51.2% to 29.9%(UMC:61.3%),and the 100-seed weight(HSW)increased by 96.0%to 8.37 g(UMC:4.27 g).Following sowing in the nursery,the seedling emergence rate(SER)increased by 6.57-fold,reaching 59.8%(UMC:7.9%).Additionally,the whole plant biomass of 6-month-old seedlings increased by 52.9%,attaining 1.56 g(UMC:1.02 g).The combined application of EFOF+NPK+Se(IV)significantly reduced the EAP,PEWP,and BSP by 56.5%,46.0%,and 56.3%,respectively,compared to the single application of Se(IV).Furthermore,these percentages decreased by 79.7%,78.9%,and 71.8%,respectively,relative to the single application of NPK compound fertilizers,and by 79.0%,74.5%,and 72.1%,respectively,compared to the single application of EFOF.Additionally,the SER increased by 34.6%,141.0%,and 287.0%,respectively,when compared to the single application of Se(IV),NPK compound fertilizers,and EFOF.[Conclusions]Enhancing the nutrient status of forest soils,particularly the concentration of Se(IV),constitutes a critical technical approach to improving the resistance of Red sandalwood to low-temperature stress during its flowering and fruiting stages,thereby preventing embryo abortion.展开更多
High-aspect-ratio aircraft are widely used in military and civilian fields,such as reconnaissance,surveillance,and attacks,due to their high lift-to-drag ratio,strong payload capability,significant endurance effect,an...High-aspect-ratio aircraft are widely used in military and civilian fields,such as reconnaissance,surveillance,and attacks,due to their high lift-to-drag ratio,strong payload capability,significant endurance effect,and good stealth performance.However,compared to conventional aircraft,high-aspect-ratio aircraft are more susceptible to gust disturbances during flight.In response to this phenomenon,a full-scale dynamic model of a high-aspect-ratio unmanned aerial vehicle was developed.Considering the coupling among control surfaces,structural forces,and aerodynamic forces,along with sensor,actuator,and delay effects,an H_(∞)control law was designed using the principle of singular value energy flow reduction and weighted function,with a PID(Proportional-Integral-Derivative)control law for comparison.The two controllers were then subjected to pulse-response and jury stability tests.Finally,wind tunnel tests were conducted to investigate the gust alleviation principle,in which gust disturbances were generated using gust generators and control surface self-excitation.The results present that the average wing root bending moment and wing tip overload under the PID control law decrease by approximately 30%,while under the H_(∞)control law,both the average wing root bending moment and wing tip overload reduction rate exceed 50%,with peaks reaching 60%.This validates the feasibility and efficiency of the designed H_(∞)controller.展开更多
The ability of queens and males of most ant species to disperse by flight has fundamentally contributed to the group’s evolutionary and ecological success and is a determining factor to take into account for biogeogr...The ability of queens and males of most ant species to disperse by flight has fundamentally contributed to the group’s evolutionary and ecological success and is a determining factor to take into account for biogeographic studies(Wagner and Liebherr 1992;Peeters and Ito 2001;Helms 2018).展开更多
The contradiction between the efficiency and the ice tolerance remains a challenge to the traditional aerodynamic design considering the icing effect.To address the problem,a new ice-tolerant concept based on the vari...The contradiction between the efficiency and the ice tolerance remains a challenge to the traditional aerodynamic design considering the icing effect.To address the problem,a new ice-tolerant concept based on the variable drooping leading edge is proposed and extended to a single-aisle commercial aircraft with the swept wing.The outer-wing and full-spanwise drooping leading edge configurations are set up to distinguish the effect of different ice tolerant strategies.The Reynolds-averaged Navier-Stokes results reveal that the stall angle of attack is delayed by 25.0%,and the maximum lift coefficient is increased by 23.3%with the full-spanwise drooping in the presence of horn-shaped ice on the wing.This improvement is primarily driven by the recovery of leading-edge suction.With the formulation of the improved delayed detached eddy simulation,the structures and the behaviors of the separated flow near the stall point are analyzed via the comparison before and after drooping the leading edge in full-spanwise.The results indicate that the suppression of the spatial development of the shedding shear layer promotes the closure of the separation bubble and mitigates the sweeping motion of the large-scale spanwise vortex.These integrated effects contribute to the enhancement of ice tolerance.展开更多
Avian wings are central to their remarkable flight ability and diverse life history strategies,including behaviors such as fighting and mating.These multifaceted functions are intricately tied to wing shape,which vari...Avian wings are central to their remarkable flight ability and diverse life history strategies,including behaviors such as fighting and mating.These multifaceted functions are intricately tied to wing shape,which varies significantly across species because of the complex interplay of evolutionary and ecological pressures.Many indices have been developed to quantify wing characteristics to facilitate the study and comparison of avian wing morphology across species.This study provides a comprehensive overview of existing quantitative methods for analyzing avian wing shapes.We then constructed a new quantification framework through the beta distribution,which can generate indices reflecting the shape of avian wings(center,dispersion,skewness,and kurtosis).Next,we used the flight feathers of 613 bird species to perform different quantitative analyses and explore the relationships between various wing shape quantification methods and life history traits,which serve as proxies for the selective forces shaping wing morphology.We find that the wing shape indices are more strongly associated with ecological variables than with morphological variables,especially for migration,habitat and territoriality.This research guides the selection of appropriate methods for wing shape analysis,contributing to a deeper understanding of avian morphology and its evolutionary drivers.展开更多
基金Fundación Pública Andaluza para la Gestión de la investigación en Salud de Sevilla"FISEVI"
文摘BACKGROUND No dynamic technique, such as tendon transfer, has been described for scapular winging due to levator scapulae or rhomboid major and minor palsies resulting from an isolated dorsal scapular nerve injury. Thus, we evaluated how the contralateral trapezius compound osteomuscular flap transfer would work in stabilizing lateral scapular winging, and the case is reported here. A literature review was also conducted, and articles relevant to the case are presented.CASE SUMMARY A 37-year-old male patient who had sustained an isolated dorsal scapular nerve injury underwent reconstructive surgery using the contralateral trapezius compound osteomuscular flap transfer technique to treat scapular winging and the consequent pain, and to restore function from the shoulder impairment. As a result, the involved shoulder showed an improved Constant-Murley score, from19.5% to 81.88%.CONCLUSION Contralateral trapezius osteomuscular flap transfer succeeded in stabilizing scapular winging in this case, improving shoulder function and affording pain relief.
基金supported by the National Natural Science Foundation of China(Grant No.12402268)the Fundamental Research Funds for the Central Universities(Grant No.30925010410)。
文摘The core components of an aircraft and the source of its lift are its wings,but lift generation is disrupted by the high temperature and pressure generated on the wing surface when an aircraft gun is fired.Here,to investigate how this process influences the aerodynamic parameters of aircraft wings,the k-ωshearstress-transport turbulence model and the nested dynamic grid technique are used to analyze numerically the transient process of the muzzle jet of a 30-mm small-caliber aircraft gun in highaltitude(10 km)flight with an incoming Mach number of Ma=0.8.For comparison,two other models are established,one with no projectile and the other with no wing.The results indicate that when the aircraft gun is fired,the muzzle jet acts on the wing,creating a pressure field thereon.The uneven distribution of high pressure greatly reduces the lift of the aircraft,causing oscillations in its drag and disrupting its dynamic balance,thereby affecting its flight speed and attitude.Meanwhile,the muzzle jet is obstructed by the wing,and its flow field is distorted and deformed,developing upward toward the wing.Because of the influence of the incoming flow,the shockwave front of the projectile changes from a smooth spherical shape to an irregular one,and the motion parameters of the projectile are also greatly affected by oscillations.The present results provide an important theoretical basis for how the guns of fighter aircraft influence the aerodynamic performance of the wings.
基金Nguyen Tat Thanh University,Ho Chi Minh City,Vietnam for supporting this study。
文摘Wing design is a critical factor in the aerodynamic performance of flapping-wing(FW)robots.Inspired by the natural wing structures of insects,bats,and birds,we explored how bio-mimetic wing vein morphologies,combined with a bio-inspired double wing clap-and-fling mechanism,affect thrust generation.This study focused on increasing vertical force and payload capacity.Through systematic experimentation with various vein configurations and structural designs,we developed innovative wings optimized for thrust production.Comprehensive tests were conducted to measure aerodynamic forces,power consumption,and wing kinematics across a range of flapping frequencies.Additionally,wings with different aspect ratios,a key factor in wing design,were fabricated and extensively evaluated.The study also examined the role of bio-inspired vein layouts on wing flexibility,a critical component in improving flight efficiency.Our findings demonstrate that the newly developed wing design led to a 20%increase in thrust,achieving up to 30 g-force(gf).This research sheds light on the clap-and-fling effect and establishes a promising framework for bio-inspired wing design,offering significant improvements in both performance and payload capacity for FW robots.
基金supported by the National Natural Science Foundation of China(Grant No.52405257)the China Postdoctoral Science Foundation(Grant No.2024M764201).
文摘Hypersonic morphing vehicle(HMV)can reconfigure aerodynamic geometries in real time,adapting to diverse needs like multi-mission profiles and wide-speed-range flight,spanwise morphing and sweep angle variation are representative large-scale wing reconfiguration modes.To meet the HMV's need for an increased lift and a lift to drag ratio during hypersonic maneuverability and cruise or reentry equilibrium glide,this paper proposes an innovative single-DOF coupled morphing-wing system.We then systematically analyze its open-loop kinematics and closed-loop connectivity constraints,and the proposed system integrates three functional modules:the preset locking/release mechanism,the coupled morphing-wing mechanism,and the integrated wing locking with active stiffness control mechanism.Experimental validation confirms stable,continuous morphing under simulated aerodynamic loads.The experimental results indicate:(i)SMA actuators exhibit response times ranging from 18 s to 160 s,providing sufficient force output for wing unlocking;(ii)The integrated wing locking with active stiffness control mechanism effectively secures wing positions while eliminating airframe clearance via SMA actuation,improving the first-order natural frequency by more than 17%;(iii)The distributed aerodynamic loading system enables precise multi-stage follow-up loading during morphing,with the coupled morphing wing maintaining stable,continuous operation under 0-3500 N normal loads and 110-140 N axial force.The proposed single-DOF coupled morphing mechanism not only simplifies and improves structural efficiency but also demonstrates superior performance in locking control,stiffness enhancement,and aerodynamic responsiveness.This establishes a foundational framework for the design of future intelligent morphing configurations and the implementation of flight control systems.
文摘Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.
基金supported by the National Natural Science Foundation of China(Grant No.12472279)。
文摘In bio-inspired flapping-wing flight,lift generation and flexible deformation are intrinsically coupled.Thus,an experimental study is conducted to reveal the fluid-structure interaction mechanism for a flexible plate undergoing pitching and plunging motion,and theoretical models are proposed to predict either lift or deformation based on a series of simplifying assumptions.It is indicated that flexible plates can effectively reduce the amplitude of lift and pitching moment coefficients during dynamic stall,with increased flexibility leading to higher load reduction.To investigate the effect of plate flexibility on lift,a definition of effective angle of attack is proposed,incorporating the pitching and plunging motion and chordwise deformation of the flexible plate,which can reduce the hysteresis effect of the lift coefficient during dynamic stall.As a consequence,a theoretical model is developed to predict lift based on observed motion and deformation.On the other hand,another theoretical model is developed to predict flexible-plate deformation utilizing aerodynamic forces,revealing the effect of leading-edge vortex evolution on passive deformation.The influence of kinematic parameters,including the maximum effective angle of attack,reduced frequency,and Strouhal number,on the aerodynamic forces is further studied.Compared with the rigid plate,flexible plates exhibit lower sensitivity of aerodynamic forces to changes in kinematic parameters due to their inherent compliance and resulting deformation.The proposed theoretical models can serve as a reference for aerodynamic and deformation prediction in bio-inspired flexible structures.
基金supported by the National Science Foundation(NSF)of the USA(Grant Nos.TIP-2140489,CBET-2313310,and CBET-2415347).
文摘An unsteady numerical simulation is conducted to examine the dynamic runback characteristics of a water film flow driven by a boundary layer airflow over a solid surface pertinent to the dynamic glaze ice accretion process over aircraft wing surfaces.The multiphase flow simulation results of the wind-driven water runback(WDWR)flow are compared quantitatively with the experimental results in terms of the time-dependent variations of the water film thickness profiles and evolution of the front contact point of the runback water film flow.The underlying mechanism of the intermittent water runback behavior is elucidated by analyzing the time evolution of the airflow velocity and vorticity fields above the runback water film flow over the solid surface.To the best knowledge of the authors,the work presented here is the first successful attempt to numerically examine the transient runback characteristics of WDWR flows.It serves as an excellent benchmark case for the development of best practices to model the important micro-physical processes responsible for the transient water transport over aircraft wing surfaces.
基金supported by the National Natural Science Foundation of China(Grant Nos.52302115,52231004)。
文摘Hafnium carbide(HfC)serves as a critical ablation-resistant coating for C/C composites used on the wing leading edges of high-speed vehicles during atmospheric re-entry[1-3].Under the action of high-temperature,oxidizing gas flow,the HfC coating forms a high-melting-point heterogeneous oxide layer,significantly delaying oxidation of the underlying material and preserving the structural integrity of the C/C composites[4].
文摘This spring, the world again faces the prospect of a bird flu outbreak Hawks, tigers, dogs and cats. These animals are not directly related in the biological chain, but they are all threatened by the same disease-the H5N1 avian flu virus.
基金supported by the Istanbul Technical University Office of Scientific Research Projects(ITUBAPSIS),under grant MYL-2022-43776。
文摘The design of unmanned aerial vehicles(UAVs)revolves around the careful selection of materials that are both lightweight and robust.Carbon fiber-reinforced polymer(CFRP)emerged as an ideal option for wing construction,with its mechanical qualities thoroughly investigated.In this study,we developed and optimized a conceptual UAV wing to withstand structural loads by establishing progressive composite stacking sequences,and we conducted a series of experimental characterizations on the resulting material.In the optimization phase,the objective was defined as weight reduction,while the Hashin damage criterion was established as the constraint for the optimization process.The optimization algorithm adaptively monitors regional damage criterion values,implementing necessary adjustments to facilitate the mitigation process in a cost-effective manner.Optimization of the analytical model using Simulia Abaqus~(TM)and a Python-based user-defined sub-routine resulted in a 34.7%reduction in the wing's structural weight after 45 iterative rounds.Then,the custom-developed optimization algorithm was compared with a genetic algorithm optimization.This comparison has demonstrated that,although the genetic algorithm explores numerous possibilities through hybridization,the custom-developed algorithm is more result-oriented and achieves optimization in a reduced number of steps.To validate the structural analysis,test specimens were fabricated from the wing's most critically loaded segment,utilizing the identical stacking sequence employed in the optimization studies.Rigorous mechanical testing revealed unexpectedly high compressive strength,while tensile and bending strengths fell within expected ranges.All observed failure loads remained within the established safety margins,thereby confirming the reliability of the analytical predictions.
基金supported by the Research Grants Council(RGC)of the Government of Hong Kong Special Administrative Region(HKSAR)with RGC/GRF Project(Grant Nos.16206321 and 14113824).
文摘Some of the most interesting areas in aerospace science and technologies are on either higher,faster,and larger systems or lower,slower,and smaller flying capabilities.In this paper,we present our perspectives on the aerodynamics related to small,fixed-wing as well as flapping-wing flight vehicles.From an evolutionary viewpoint,flyers have gone through many iterations,adaptations,and optimizations to balance their biological functions,including flight.In the low-Reynolds-number regime,the aerodynamic characteristics around a solid object differ from those observed at the scale of passenger-airplanes.Consequently,the optimal airfoil and wing shapes vary with vehicle size.As vehicle dimensions vary,non-proportional scaling between surface areas and weight shifts the dominance of physical mechanisms,leading to distinct operational parameters and technical requirements.With smaller flight vehicles,structural flexibility as well as anisotropic material properties become more pronounced,which causes qualitative changes in aerodynamics.The flapping motion of the wings,the interactions between wings,the synergistic characteristics of wing and tail,and the development of soft structures for better agility and flight performance are discussed.Low-Reynolds-number aerodynamics require collaborative innovation to optimize shape,motion,and structure of vehicles in accordance with the scaling laws.Together,progress on these fronts is reshaping the design paradigm of air vehicles and other types of robots with shrinking physical dimensions and more versatile capabilities to meet wider ranges of missions.
基金co-supported by the National Natural Science Foundation of China(No.12472332)。
文摘This paper investigates the influence of the spanwise-distributed trailing-edge camber morphing on the dynamic stall characteristics of a finite-span wing at Re=2×10^(5).The mathematical model of the spanwise-distributed trailing-edge camber morphing is established based on Chebyshev polynomials,and the deformed wing surface is modeled by a spline surface according to the rib's morphing in the chordwise direction.The Computational Fluid Dynamics(CFD)method is adopted to obtain flow-field results and aerodynamic forces.The SST-γmodel is introduced and the overset mesh technique is adopted.The numerical results show that the spanwisedistributed trailing-edge morphing obviously changes the aerodynamic and energy transfer characteristics of the dynamic stall.Especially when the phase difference between the trailing-edge motion and the wing pitch is-π/2,the interaction between the three-dimensional(3-D)Leading-Edge Vortex(LEV)and Trailing-Edge Vortex(TEV)is strengthened,and the work done by the aerodynamic force turns negative.This indicates that the trailing-edge deformation has the potential to suppress the oscillation amplitude of stall flutter.We also found that as the trailing-edge camber morphing varies more complexly along the spanwise direction,the suppression effect decreases accordingly.
基金supported by the National Key Research and Development Program of China(No.2020YFB1708303)the National Natural Science Foundation of China(Nos.U1808215 and 12072058)the Fundamental Research Funds for the Central Universities of China(DUT20LK02).
文摘Honeycomb structures of shape memory alloy(SMA)have become one of the most promising materials for flexible skins of morphing aircraft due to their excellent mechanical properties.However,due to the nonlinear material and geometric large deformation,the SMA honeycomb exhibits significant and complex nonlinearity in the skin and there is a lack of relevant previous research.In this paper,the nonlinear properties of the SMA honeycomb structure with arbitrary geometry are investigated for the first time for large deformation flexible skin applications by theoretical and experimental analysis.Firstly,a novel theoretical model of SMA honeycomb structure considering both material and geometric nonlinearity is proposed,and the corresponding calculation method of nonlinear governing equations is given based upon the shooting method and Runge–Kutta method.Then,the tensile behaviors of four kinds of SMA honeycomb structures,i.e.,U-type,V-type,cosine-type,and trapezoid-type,are analyzed and predicted by the proposed theoretical model and compared with the finite element analysis(FEA)results.Moreover,the tensile experiments were carried out by stretching U-type and V-type honeycomb structures to a global strain of 60%and 40%,respectively,to perform large deformation analysis and verify the theoretical model.Finally,experimental verification and finite element validation show that the curves of the theoretical model results,experimental results,and simulation results are in good agreement,illustrating the generalizability and accuracy of the proposed theoretical model.The theoretical model and experimental investigations in this paper are considered to provide an effective foundation for analyzing and predicting the mechanical behavior of SMA honeycomb flexible skins with large extensional deformations.
基金The funding for this publication was provided by Johannes Kepler University(JKU),Linz.Special thanks to Prof.Zongmin DENG from Beihang University for his invaluable guidance,insightful feedback,and constructive criticism,which greatly enhanced the quality of this manuscript.We extend our heartfelt gratitude to the PARSIFAL team for providing the supporting materials,which inspired this study.
文摘The optimization of wings typically relies on computationally intensive high-fidelity simulations,which restrict the quick exploration of design spaces.To address this problem,this paper introduces a methodology dedicated to optimizing box wing configurations using low-fidelity data driven machine learning approach.This technique showcases its practicality through the utilization of a tailored low-fidelity machine learning technique,specifically designed for early-stage wing configuration.By employing surrogate model trained on small dataset derived from low-fidelity simulations,our method aims to predict outputs within an acceptable range.This strategy significantly mitigates computational costs and expedites the design exploration process.The methodology's validation relies on its successful application in optimizing the box wing of PARSIFAL,serving as a benchmark,while the primary focus remains on optimizing the newly designed box wing by Bionica.Applying this method to the Bionica configuration led to a notable 14%improvement in overall aerodynamic effciency.Furthermore,all the optimized results obtained from machine learning model undergo rigorous assessments through the high-fidelity RANS analysis for confirmation.This methodology introduces innovative approach that aims to streamline computational processes,potentially reducing the time and resources required compared to traditional optimization methods.
基金Supported by National Natural Science Foundation of China(31270674)Science and Technology Plan Project of Zhaoqing City(2019N012)National Undergraduate Science and Technology Innovation Training Program of China(202210580007).
文摘[Objectives]To explore the effect of selenium(Se)on inhibiting embryo abortion and enhancing seedling cultivation quality of Red sandalwood(Pterocarpus santalinus).[Methods]Based on prior cultivation practices and experimental research,three categories comprising 13 forest soil nutrient management schemes were designed to investigate the synergistic effects of Se,NPK compound fertilizers,and enzyme-microbe fermented organic fertilizers(EFOF)on embryo abortion,winged pod development,and seedling quality of Red sandalwood.[Results]Increasing the Se content in the soil,particularly in the form of selenite/Se(IV),within one month following the harvest of Red sandalwood pods and within two months prior to flower withering,significantly reduced embryo abortion percentage(EAP),and consequently improved seed quality and yield per plant.The effect of Se application was markedly greater than that of the single application of nitrogen(N),phosphorus(P),potassium(K),boron(B)fertilizers,or organic fertilizers.Furthermore,when Se was applied in combination with NPK compound fertilizers and EFOF,these beneficial effects were significantly enhanced.When Se(IV)was applied individually,the EAP decreased by 62.4%,reaching 24.8% at 8 weeks after flower withering(compared to 65.9%in the unmanaged control,UMC).Following winged pod maturation,the percentage of empty winged pods(PEWP)declined by 65.2% to 16.8%(UMC:48.2%),the average individual winged pod weight(IWPW)increased by 69.1%to 0.690 g per fruit(UMC:0.408 g),and the winged pod yield(WPY)rose by 214.8% to 4.03 kg(UMC:1.28 kg).Additionally,the blasted seed percentage(BSP)was reduced by 51.2% to 29.9%(UMC:61.3%),and the 100-seed weight(HSW)increased by 96.0%to 8.37 g(UMC:4.27 g).Following sowing in the nursery,the seedling emergence rate(SER)increased by 6.57-fold,reaching 59.8%(UMC:7.9%).Additionally,the whole plant biomass of 6-month-old seedlings increased by 52.9%,attaining 1.56 g(UMC:1.02 g).The combined application of EFOF+NPK+Se(IV)significantly reduced the EAP,PEWP,and BSP by 56.5%,46.0%,and 56.3%,respectively,compared to the single application of Se(IV).Furthermore,these percentages decreased by 79.7%,78.9%,and 71.8%,respectively,relative to the single application of NPK compound fertilizers,and by 79.0%,74.5%,and 72.1%,respectively,compared to the single application of EFOF.Additionally,the SER increased by 34.6%,141.0%,and 287.0%,respectively,when compared to the single application of Se(IV),NPK compound fertilizers,and EFOF.[Conclusions]Enhancing the nutrient status of forest soils,particularly the concentration of Se(IV),constitutes a critical technical approach to improving the resistance of Red sandalwood to low-temperature stress during its flowering and fruiting stages,thereby preventing embryo abortion.
基金supported by the National Natural Science Foundation of China(Nos.12272104,U22B2013).
文摘High-aspect-ratio aircraft are widely used in military and civilian fields,such as reconnaissance,surveillance,and attacks,due to their high lift-to-drag ratio,strong payload capability,significant endurance effect,and good stealth performance.However,compared to conventional aircraft,high-aspect-ratio aircraft are more susceptible to gust disturbances during flight.In response to this phenomenon,a full-scale dynamic model of a high-aspect-ratio unmanned aerial vehicle was developed.Considering the coupling among control surfaces,structural forces,and aerodynamic forces,along with sensor,actuator,and delay effects,an H_(∞)control law was designed using the principle of singular value energy flow reduction and weighted function,with a PID(Proportional-Integral-Derivative)control law for comparison.The two controllers were then subjected to pulse-response and jury stability tests.Finally,wind tunnel tests were conducted to investigate the gust alleviation principle,in which gust disturbances were generated using gust generators and control surface self-excitation.The results present that the average wing root bending moment and wing tip overload under the PID control law decrease by approximately 30%,while under the H_(∞)control law,both the average wing root bending moment and wing tip overload reduction rate exceed 50%,with peaks reaching 60%.This validates the feasibility and efficiency of the designed H_(∞)controller.
基金funded by the“Departments of Excellence”program of the Italian Ministry for University and Research(MIUR,2018-2022 and MUR,2023-2027).
文摘The ability of queens and males of most ant species to disperse by flight has fundamentally contributed to the group’s evolutionary and ecological success and is a determining factor to take into account for biogeographic studies(Wagner and Liebherr 1992;Peeters and Ito 2001;Helms 2018).
基金co-supported by the National Natural Science Foundation of China(Nos.12302300,12272312,12372288 and 12388101)the Open Fund of Key Laboratory of Icing and Anti/De-icing,China(No.IADL20220413)the 1-0 Major Engineering Science Problem Project of Northwestern Polytechnical University(No.G2024KY0613)。
文摘The contradiction between the efficiency and the ice tolerance remains a challenge to the traditional aerodynamic design considering the icing effect.To address the problem,a new ice-tolerant concept based on the variable drooping leading edge is proposed and extended to a single-aisle commercial aircraft with the swept wing.The outer-wing and full-spanwise drooping leading edge configurations are set up to distinguish the effect of different ice tolerant strategies.The Reynolds-averaged Navier-Stokes results reveal that the stall angle of attack is delayed by 25.0%,and the maximum lift coefficient is increased by 23.3%with the full-spanwise drooping in the presence of horn-shaped ice on the wing.This improvement is primarily driven by the recovery of leading-edge suction.With the formulation of the improved delayed detached eddy simulation,the structures and the behaviors of the separated flow near the stall point are analyzed via the comparison before and after drooping the leading edge in full-spanwise.The results indicate that the suppression of the spatial development of the shedding shear layer promotes the closure of the separation bubble and mitigates the sweeping motion of the large-scale spanwise vortex.These integrated effects contribute to the enhancement of ice tolerance.
基金supported by the National Natural Science Foundation of China(No.32170491)the Scientific Research Team Project of the College of Life Sciences,Beijing Normal University in 2024。
文摘Avian wings are central to their remarkable flight ability and diverse life history strategies,including behaviors such as fighting and mating.These multifaceted functions are intricately tied to wing shape,which varies significantly across species because of the complex interplay of evolutionary and ecological pressures.Many indices have been developed to quantify wing characteristics to facilitate the study and comparison of avian wing morphology across species.This study provides a comprehensive overview of existing quantitative methods for analyzing avian wing shapes.We then constructed a new quantification framework through the beta distribution,which can generate indices reflecting the shape of avian wings(center,dispersion,skewness,and kurtosis).Next,we used the flight feathers of 613 bird species to perform different quantitative analyses and explore the relationships between various wing shape quantification methods and life history traits,which serve as proxies for the selective forces shaping wing morphology.We find that the wing shape indices are more strongly associated with ecological variables than with morphological variables,especially for migration,habitat and territoriality.This research guides the selection of appropriate methods for wing shape analysis,contributing to a deeper understanding of avian morphology and its evolutionary drivers.
