Improvements in aero-engine performance have made the structures of the aero-engine components increasingly complex.To better adapt to the processing requirements of narrow twisted channels such as an integral shroude...Improvements in aero-engine performance have made the structures of the aero-engine components increasingly complex.To better adapt to the processing requirements of narrow twisted channels such as an integral shrouded blisk,this study proposes an innovative method of electrochemical cutting in which a flexible tube electrode is controlled by online deformation during processing.In this study,the processing principle of electrochemical cutting with a flexible electrode for controlled online deformation(FECC)was revealed for the first time.The online deformation process of flexible electrodes and the machining process of profiles were analysed in depth,and the corresponding theoretical models were established.Conventional electrochemical machining(ECM)is a multi-physical field-coupled process involving electric and flow fields.In FECC,classical mechanics are introduced into the tool cathode,which must be loaded at all times during the machining process.Therefore,in this study,before and after the deformation of the flexible electrode,a corresponding simulation study was conducted to understand the influence of the online deformation of the flexible electrode on the flow and electric fields.The feasibility of flexible electrodes for online deformation and the validity of the theoretical model were verified by deformation measurements and in situ observation experiments.Finally,the method was successfully applied to the machining of nickel-based high-temperature alloys,and different specifications of flexible electrodes were used to complete the machining of the corresponding complex profiles,thereby verifying the feasibility and versatility of the method.The method proposed in this study breaks the tradition of using a non-deformable cathode for ECM and adopts a flexible electrode that can be deformed during the machining process as the tool cathode,which improves machining flexibility and provides a valuable reference to promote the ECM of complex profiles.展开更多
Since the first design of tactile sensors was proposed by Harmon in 1982,tactile sensors have evolved through four key phases:industrial applications(1980s,basic pressure detection),miniaturization via MEMS(1990s),fle...Since the first design of tactile sensors was proposed by Harmon in 1982,tactile sensors have evolved through four key phases:industrial applications(1980s,basic pressure detection),miniaturization via MEMS(1990s),flexible electronics(2010s,stretchable materials),and intelligent systems(2020s-present,AI-driven multimodal sensing).With the innovation of material,processing techniques,and multimodal fusion of stimuli,the application of tactile sensors has been continuously expanding to a diversity of areas,including but not limited to medical care,aerospace,sports and intelligent robots.Currently,researchers are dedicated to develop tactile sensors with emerging mechanisms and structures,pursuing high-sensitivity,high-resolution,and multimodal characteristics and further constructing tactile systems which imitate and approach the performance of human organs.However,challenges in the combination between the theoretical research and the practical applications are still significant.There is a lack of comprehensive understanding in the state of the art of such knowledge transferring from academic work to technical products.Scaled-up production of laboratory materials faces fatal challenges like high costs,small scale,and inconsistent quality.Ambient factors,such as temperature,humidity,and electromagnetic interference,also impair signal reliability.Moreover,tactile sensors must operate across a wide pressure range(0.1 k Pa to several or even dozens of MPa)to meet diverse application needs.Meanwhile,the existing algorithms,data models and sensing systems commonly reveal insufficient precision as well as undesired robustness in data processing,and there is a realistic gap between the designed and the demanded system response speed.In this review,oriented by the design requirements of intelligent tactile sensing systems,we summarize the common sensing mechanisms,inspired structures,key performance,and optimizing strategies,followed by a brief overview of the recent advances in the perspectives of system integration and algorithm implementation,and the possible roadmap of future development of tactile sensors,providing a forward-looking as well as critical discussions in the future industrial applications of flexible tactile sensors.展开更多
The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,fle...The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,flexible memristors exhibit great application potential in emulating artificial synapses for highefficiency and low power consumption neuromorphic computing.This paper provides comprehensive overview of flexible memristors from perspectives of development history,material system,device structure,mechanical deformation method,device performance analysis,stress simulation during deformation,and neuromorphic computing applications.The recent advances in flexible electronics are summarized,including single device,device array and integration.The challenges and future perspectives of flexible memristor for neuromorphic computing are discussed deeply,paving the way for constructing wearable smart electronics and applications in large-scale neuromorphic computing and high-order intelligent robotics.展开更多
As Internet of Things(IoT)applications expand,Mobile Edge Computing(MEC)has emerged as a promising architecture to overcome the real-time processing limitations of mobile devices.Edge-side computation offloading plays...As Internet of Things(IoT)applications expand,Mobile Edge Computing(MEC)has emerged as a promising architecture to overcome the real-time processing limitations of mobile devices.Edge-side computation offloading plays a pivotal role in MEC performance but remains challenging due to complex task topologies,conflicting objectives,and limited resources.This paper addresses high-dimensional multi-objective offloading for serial heterogeneous tasks in MEC.We jointly consider task heterogeneity,high-dimensional objectives,and flexible resource scheduling,modeling the problem as a Many-objective optimization.To solve it,we propose a flexible framework integrating an improved cooperative co-evolutionary algorithm based on decomposition(MOCC/D)and a flexible scheduling strategy.Experimental results on benchmark functions and simulation scenarios show that the proposed method outperforms existing approaches in both convergence and solution quality.展开更多
An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduc...An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.展开更多
To meet the demand for the machining of blisks with narrow cascade channels and twisted blade profiles,especially integral shrouded blisks with shrouds,this paper innovatively proposes a method for dynamic deformation...To meet the demand for the machining of blisks with narrow cascade channels and twisted blade profiles,especially integral shrouded blisks with shrouds,this paper innovatively proposes a method for dynamic deformation electrochemical cutting of flexible electrodes with arrayed group slit structure.By applying torque to both ends of the flexible electrode,the proposed method produces bending deformation and realizes the processing of a twisted profile.The flexible electrode is an important carrier of this method,and its properties such as elasticity,rigidity,and flow field uniformity have a crucial impact on smooth processing.Therefore,this paper proposes a design theory of flexible electrodes with an arrayed group slit structure and designs flexible electrodes with variable cross-sections.Compared with traditional uniform section tube electrode,the designed flexible electrode was subjected to the corresponding mechanical simulation,flow field simulation,and fluid–structure interaction simulation to investigate the elasticity,rigidity,and flow field uniformity of the flexible electrode.In addition,a deformation device of flexible electrodes was constructed and the corresponding experiments were carried out.Simulations and experiments demonstrate that flexible electrodes with arrayed group slit structures have good comprehensive performance.Finally,typical components were successfully machined to verify the feasibility of the proposed method and the rationality of the designed flexible electrode.It is shown that the proposed method has great potential for the machining of distorted profiles and provides a new idea for the machining of complex profiles.展开更多
The phenomena of thermal runaway and accidental deformation due to external stresses in lithium batteries or film capacitors consti-tute their primary failure mechanisms.Therefore,monitoring and early warning of overh...The phenomena of thermal runaway and accidental deformation due to external stresses in lithium batteries or film capacitors consti-tute their primary failure mechanisms.Therefore,monitoring and early warning of overheating or localized strain are of great value for the safe use of lithium batteries or film capacitors;however,this function usually requires a system of multiple complex sensors.The realization of the above multiple hazards using a single sensor for monitoring and alarm functions has not been reported.Here,we exploit the thermally induced conductivity and modulus change during solid-liquid conversion of low melting point polyalloys to modulate the electronic relaxation polariza-tion and interfacial polarization in the composites for dielectric switching,and the reduction of alloy particle spacing during bending/compres-sive strain can be used to generate switchable tunneling effects for insulator-conductor transition.By synergizing dielectric switching and insula-tor-conductor transition,the final flexible thermoplastic polyurethane elastomer/low-melting-point polyalloy composite film achieves the func-tional integration of multi-level overheating warning and small deformation monitoring.展开更多
In this study, the results of 1-g shaking table tests performed on small-scale flexible cantilever wallmodels retaining composite backfill made of a deformable geofoam inclusion and granular cohesionlessmaterial were ...In this study, the results of 1-g shaking table tests performed on small-scale flexible cantilever wallmodels retaining composite backfill made of a deformable geofoam inclusion and granular cohesionlessmaterial were presented. Two different polystyrene materials were utilized as deformable inclusions.Lateral dynamic earth pressures and wall displacements at different elevations of the retaining wallmodel were monitored during the tests. The earth pressures and displacements of the retaining wallswith deformable inclusions were compared with those of the models without geofoam inclusions.Comparisons indicated that geofoam panels of low stiffness installed against the retaining wall modelaffect displacement and dynamic lateral pressure profile along the wall height. Depending on the inclusioncharacteristics and the wall flexibility, up to 50% reduction in dynamic earth pressures wasobserved. The efficiency of load and displacement reduction decreased as the flexibility ratio of the wallmodel increased. On the other hand, dynamic load reduction efficiency of the deformable inclusionincreased as the amplitude and frequency ratio of the seismic excitation increased. Relative flexibility ofthe deformable layer （the thickness and the elastic stiffness of the polystyrene material） played animportant role in the amount of load reduction. Dynamic earth pressure coefficients were compared withthose calculated with an analytical approach. Pressure coefficients calculated with this method werefound to be in good agreement with the results of the tests performed on the wall model having lowflexibility ratio. It was observed that deformable inclusions reduce residual wall stresses observed at theend of seismic excitation thus contributing to the post-earthquake stability of the retaining wall. Thegraphs presented within this paper regarding the dynamic earth pressure coefficients versus the wallflexibility and inclusion characteristics may serve for the seismic design of full-scale retaining walls withdeformable polystyrene inclusions. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.展开更多
As human aeronautic and aerospace technology continues to prosper and the aerial flight space domain further expands,traditional fixed-shape air vehicles have been confronted with difficulties in satisfying complex mi...As human aeronautic and aerospace technology continues to prosper and the aerial flight space domain further expands,traditional fixed-shape air vehicles have been confronted with difficulties in satisfying complex missions in cross-domain scenarios.Owing to their flexible and deformable appearance,morphing air vehicles are expected to realize cross-domain intelligent flight,thus emerging as the most subversive strategic development trend and research focus in aeronautic and aerospace fields.This paper primarily reviews the research background and challenges of flexible and deformable cross-domain intelligent flight,proposing a corresponding research framework and mode as well as exploring the scientific issues and state-of-the-art solutions,where key research progress is introduced.The explorations covered in this paper also provide ideas and directions for the study of deformable cross-domain intelligent flight,which has critical scientific significance in promoting the study itself.展开更多
This work presents a novel highly adaptable flexible soft glove composed of multimode deformable three-jointed soft fingers.The soft fingers are assembled by soft actuators and plastic materials that can be driven and...This work presents a novel highly adaptable flexible soft glove composed of multimode deformable three-jointed soft fingers.The soft fingers are assembled by soft actuators and plastic materials that can be driven and controlled with single Degree of Freedom(DOF).A variety of different soft actuators are used as joint drive components to meet the motion requirements of fingers under different working conditions.We established a theoretical model to describe the deflection of the soft actuators based on reciprocal theorems.In addition,the finite-element method(FEM)was used to simulate the curvature change of the soft actuator and the soft finger,the soft actuators theoretical and simulation results were verified by experiments,and the multimode deformable soft fingers were simulated by FEM.Finally,a five-finger soft rehabilitation glove was prototyped and presented experimentally where the flexibility and functionality endowed by the soft fingers were demonstrated and highlighted.The versatility was also showcased in the applications.展开更多
Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabricati...Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabrication,low-power consumption,fast response times,and versatility.Graphene,known for its exceptional mechanical properties,high electron mobility,and biocompatibility,is an ideal material for FET channels and sensors.The combination of graphene and FETs has given rise to flexible graphene field-effect transistors(FGFETs),driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors.Here,we first provide a brief overview of the basic structure,operating mechanism,and evaluation parameters of FGFETs,and delve into their material selection and patterning techniques.The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities.We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors,focusing on the key aspects of constructing high-quality flexible biomedical sensors.Finally,we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors.This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing.展开更多
The complex wiring,bulky data collection devices,and difficulty in fast and on-site data interpretation significantly limit the practical application of flexible strain sensors as wearable devices.To tackle these chal...The complex wiring,bulky data collection devices,and difficulty in fast and on-site data interpretation significantly limit the practical application of flexible strain sensors as wearable devices.To tackle these challenges,this work develops an artificial intelligenceassisted,wireless,flexible,and wearable mechanoluminescent strain sensor system(AIFWMLS)by integration of deep learning neural network-based color data processing system(CDPS)with a sandwich-structured flexible mechanoluminescent sensor(SFLC)film.The SFLC film shows remarkable and robust mechanoluminescent performance with a simple structure for easy fabrication.The CDPS system can rapidly and accurately extract and interpret the color of the SFLC film to strain values with auto-correction of errors caused by the varying color temperature,which significantly improves the accuracy of the predicted strain.A smart glove mechanoluminescent sensor system demonstrates the great potential of the AIFWMLS system in human gesture recognition.Moreover,the versatile SFLC film can also serve as a encryption device.The integration of deep learning neural network-based artificial intelligence and SFLC film provides a promising strategy to break the“color to strain value”bottleneck that hinders the practical application of flexible colorimetric strain sensors,which could promote the development of wearable and flexible strain sensors from laboratory research to consumer markets.展开更多
In this paper, nonlinear modeling for flexible multibody system with large deformation is investigated. Absolute nodal coordinates are employed to describe the displacement, and variational motion equations of a flexi...In this paper, nonlinear modeling for flexible multibody system with large deformation is investigated. Absolute nodal coordinates are employed to describe the displacement, and variational motion equations of a flexible body are derived on the basis of the geometric nonlinear theory, in which both the shear strain and the transverse normal strain are taken into account. By separating the inner and the boundary nodal coordinates, the motion equations of a flexible multibody system are assembled. The advantage of such formulation is that the constraint equations and the forward recursive equations become linear because the absolute nodal coordinates are used. A spatial double pendulum connected to the ground with a spherical joint is simulated to investigate the dynamic performance of flexible beams with large deformation. Finally, the resultant constant total energy validates the present formulation.展开更多
In this paper, the substructuring technique is extended for the dynamics simulation of flexible beams with large deformation. The dynamics equation of a spatial straight beam undergoing large displacement and small de...In this paper, the substructuring technique is extended for the dynamics simulation of flexible beams with large deformation. The dynamics equation of a spatial straight beam undergoing large displacement and small deformation is deduced by using the Jourdain variation principle and the model synthesis method. The longitudinal shortening effect due to the transversal deformation is taken into consideration in the dynamics equation. In this way, the geometric stiffening effect, which is also called stress stiffening effect, is accounted for in the dynamics equation. The transfer equation of the flexible beam is obtained by assembling the dynamics equation and the kinematic relationship between the two connection points of the flexible beam. Treating a flexible beam with small deformation as a substructure, one can solve the dynamics of a flexible beam with large deformation by using the substructuring technique and the transfer matrix method. The dynamics simulation of a flexible beam with large deformation is carried out by using the proposed approach and the results are verified by comparing with those obtained from Abaqus software.展开更多
The flexible rolling process(FRP) is a novel three-dimensional(3 D) forming process that combines the multipoint and traditional rolling forming. The principle of FRP is based on thickness thinning, so the deformation...The flexible rolling process(FRP) is a novel three-dimensional(3 D) forming process that combines the multipoint and traditional rolling forming. The principle of FRP is based on thickness thinning, so the deformation path significantly impacts the forming effect. In this study, the multistep forming process with different deformation paths was introduced to improve the forming effect of FRP. For instance, with the convex surface part, three finite element models of multistep FRP(MSFRP) were established. The corresponding numerical simulations and forming experiments performed among different deformation paths showed the surface part with a longer effective forming region was obtained and the forming regions with more steps in MSFRP were smoother. Thus, the sheet-metal utilization rate was greatly improved. Moreover, the MSFRP can improve the longitudinal bending effect dramatically and thereby endowing the forming part with a better forming effect. Therefore, MSFRP is a prospective method for broad applications.展开更多
The flexible inner pressure bolt is a new kind and new structural bolt (anchor rod). A number of structural improvements and performance test have been carried out. The bolt has superior compatibility to the soft crag...The flexible inner pressure bolt is a new kind and new structural bolt (anchor rod). A number of structural improvements and performance test have been carried out. The bolt has superior compatibility to the soft crag and the large distortion tunnel with its flexibility. In order to study its stress, deformation and interaction mechanism thoroughly, a number of large distortion calcula- tions and analyses have been carried out on the bolt by FEM (finite element method), especially with the ANSYS software, based on the updated Lagrangian law. The results show that the maximum stress of the inner wall of the bolt is consistent with an elastic analytic solution. The maximum stress on the body occurs in the vicinity of the enhancement material. The link enhancement of the body seems to be quite essential. The experimental results indicate that the maximum injection pressure in the bolt is 2.5 MPa without link enhancement and 8.3 MPa with the enhancement. This link enhancement effect is highly significant. These results provide some basis for the design, application and anchoring stress analysis of the bolt.展开更多
The Flapping Rotary Wing(FRW)is a micro air vehicle wing layout coupling flapping,pitching,and rotating motions.It can gain bencfits in high lift from a fast passive rotating motion,which is tightly related to the pas...The Flapping Rotary Wing(FRW)is a micro air vehicle wing layout coupling flapping,pitching,and rotating motions.It can gain bencfits in high lift from a fast passive rotating motion,which is tightly related to the passive pitching motion directly caused by wing flexible deformation.Therefore,flexible deformation is crucial for the wing kinematics and aerodynamic performance of an FRW.In this paper,we explored the effct of flexibility on wing kinematics and acrodynamics on the basis of a mechanical FRW model.A photogrammetric method was adopted to capture motion images according to which wing orientations and deformations were reconstructed.Corresponding acrodynamic force was computed using computational fluid dynamic method,and wing kinematics and deformations were used as simulation inputs.The experimental measurements presented the real orientation and deformation pattem of a real FRW.The wing passive deformation of a high-intensity FRW was found to be mainly caused by inertial force,and a linear positive spanwise twist was observed in the FRW.The effects of wing deformation on aerodynamic force production and the underlying mechanism were addressed.Results showed that lift augment,rotating moment enhancement,and power efficiency improvement can be achieved when a wing becomes flexible.Wing spanwise twist mainly accounts for these changes in aerodynamics,and increment in spanwise twist could further contributes to aerodynamic improvement.展开更多
T-joint titanium alloy structures are commonly used in aircraft manufacturing,and their laser welding process is relatively mature,but due to the strict requirements of the airplane production,the angular deformation ...T-joint titanium alloy structures are commonly used in aircraft manufacturing,and their laser welding process is relatively mature,but due to the strict requirements of the airplane production,the angular deformation caused by uneven heat input across the sheet is still not negligible,so active control needs to be imposed.In this paper,an active deformation control method based on programmable multi-point flexible support is proposed and validated.In response to the problem that the traditional rigid clamping and pre-stressing are not adapted to the T-structure thin sheet,this study has designed a multi-point flexible support with microcontroller and electric actuators,which can monitor the stress state of the current support position in real time during the welding process and make dynamic adjustment,so that the weld deformation could be effectively reduced in this way.展开更多
Electrospinning technology has emerged as a promising method for fabricating flexible lithium-ion batter-ies(FLIBs)due to its ability to create materials with desir-able properties for energy storage applications.FLIB...Electrospinning technology has emerged as a promising method for fabricating flexible lithium-ion batter-ies(FLIBs)due to its ability to create materials with desir-able properties for energy storage applications.FLIBs,which are foldable and have high energy densities,are be-coming increasingly important as power sources for wear-able devices,flexible electronics,and mobile energy applica-tions.Carbon materials,especially carbon nanofibers,are pivotal in improving the performance of FLIBs by increas-ing electrical conductivity,chemical stability,and surface area,as well as reducing costs.These materials also play a significant role in establishing conducting networks and im-proving structural integrity,which are essential for extend-ing the cycle life and enhancing the safety of the batteries.This review considers the role of electrospinning in the fabrication of critical FLIB components,with a particular emphasis on the integration of carbon materials.It explores strategies to optimize FLIB performance by fine-tuning the electrospinning para-meters,such as electric field strength,spinning rate,solution concentration,and carbonization process.Precise control over fiber properties is crucial for enhancing battery reliability and stability during folding and bending.It also highlights the latest research findings in carbon-based electrode materials,high-performance electrolytes,and separator structures,discussing the practical challenges and opportunities these materials present.It underscores the significant impact of carbon materials on the evolution of FLIBs and their potential to shape future energy storage technologies.展开更多
Photodetectors with weak-light detection capabilities play an indispensable role in various crucial fields such as health monitors,imaging,optical communication,and etc.Nevertheless,the detection of weak light signals...Photodetectors with weak-light detection capabilities play an indispensable role in various crucial fields such as health monitors,imaging,optical communication,and etc.Nevertheless,the detection of weak light signals is often severely interfered by multiple factors such as background light,dark noise and circuit noise,making it difficult to accurately capture signals.While traditional technologies like silicon photomultiplier tubes excel in sensitivity,their high cost and inherent fragility restrict their widespread application.Against this background,perovskite materials have rapidly emerged as a research focus in the field of photodetection due to their simple preparation processes and exceptional optoelectronic properties.Not only are the preparation processes of perovskite materials straightforward and cost-effective,but more importantly,they can be flexibly integrated into flexible and stretchable substrates.This characteristic significantly compensates for the shortcomings of traditional rigid electronic devices in specific application scenarios,opening up entirely new possibilities for photodetection technology.Herein,recent advances in perovskite light detection technology are reviewed.Firstly,the chemical and physical properties of perovskite materials are discussed,highlighting their remarkable advantages in weak-light detection.Subsequently,the review systematically organizes various preparation techniques of perovskite materials and analyses their advantages in different application scenarios.Meanwhile,from the two core dimensions of performance improvement and light absorption enhancement,the key strategies of improving the performance of perovskite weak-light photodetectors are explored.Finally,the review concludes with a brief summary and a discussion on the potential challenges that may arise in the further development of perovskite devices.展开更多
基金supported by the National Natural Science Foundation of China(52375443)the Innovative Research Group Project of the National Natural Science Foundation of China(51921003).
文摘Improvements in aero-engine performance have made the structures of the aero-engine components increasingly complex.To better adapt to the processing requirements of narrow twisted channels such as an integral shrouded blisk,this study proposes an innovative method of electrochemical cutting in which a flexible tube electrode is controlled by online deformation during processing.In this study,the processing principle of electrochemical cutting with a flexible electrode for controlled online deformation(FECC)was revealed for the first time.The online deformation process of flexible electrodes and the machining process of profiles were analysed in depth,and the corresponding theoretical models were established.Conventional electrochemical machining(ECM)is a multi-physical field-coupled process involving electric and flow fields.In FECC,classical mechanics are introduced into the tool cathode,which must be loaded at all times during the machining process.Therefore,in this study,before and after the deformation of the flexible electrode,a corresponding simulation study was conducted to understand the influence of the online deformation of the flexible electrode on the flow and electric fields.The feasibility of flexible electrodes for online deformation and the validity of the theoretical model were verified by deformation measurements and in situ observation experiments.Finally,the method was successfully applied to the machining of nickel-based high-temperature alloys,and different specifications of flexible electrodes were used to complete the machining of the corresponding complex profiles,thereby verifying the feasibility and versatility of the method.The method proposed in this study breaks the tradition of using a non-deformable cathode for ECM and adopts a flexible electrode that can be deformed during the machining process as the tool cathode,which improves machining flexibility and provides a valuable reference to promote the ECM of complex profiles.
基金the financial support of the National Natural Science Foundation of China(NO.52173028)。
文摘Since the first design of tactile sensors was proposed by Harmon in 1982,tactile sensors have evolved through four key phases:industrial applications(1980s,basic pressure detection),miniaturization via MEMS(1990s),flexible electronics(2010s,stretchable materials),and intelligent systems(2020s-present,AI-driven multimodal sensing).With the innovation of material,processing techniques,and multimodal fusion of stimuli,the application of tactile sensors has been continuously expanding to a diversity of areas,including but not limited to medical care,aerospace,sports and intelligent robots.Currently,researchers are dedicated to develop tactile sensors with emerging mechanisms and structures,pursuing high-sensitivity,high-resolution,and multimodal characteristics and further constructing tactile systems which imitate and approach the performance of human organs.However,challenges in the combination between the theoretical research and the practical applications are still significant.There is a lack of comprehensive understanding in the state of the art of such knowledge transferring from academic work to technical products.Scaled-up production of laboratory materials faces fatal challenges like high costs,small scale,and inconsistent quality.Ambient factors,such as temperature,humidity,and electromagnetic interference,also impair signal reliability.Moreover,tactile sensors must operate across a wide pressure range(0.1 k Pa to several or even dozens of MPa)to meet diverse application needs.Meanwhile,the existing algorithms,data models and sensing systems commonly reveal insufficient precision as well as undesired robustness in data processing,and there is a realistic gap between the designed and the demanded system response speed.In this review,oriented by the design requirements of intelligent tactile sensing systems,we summarize the common sensing mechanisms,inspired structures,key performance,and optimizing strategies,followed by a brief overview of the recent advances in the perspectives of system integration and algorithm implementation,and the possible roadmap of future development of tactile sensors,providing a forward-looking as well as critical discussions in the future industrial applications of flexible tactile sensors.
基金supported by the NSFC(12474071)Natural Science Foundation of Shandong Province(ZR2024YQ051)+5 种基金Open Research Fund of State Key Laboratory of Materials for Integrated Circuits(SKLJC-K2024-12)the Shanghai Sailing Program(23YF1402200,23YF1402400)Natural Science Foundation of Jiangsu Province(BK20240424)Taishan Scholar Foundation of Shandong Province(tsqn202408006)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTB002)the Qilu Young Scholar Program of Shandong University.
文摘The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,flexible memristors exhibit great application potential in emulating artificial synapses for highefficiency and low power consumption neuromorphic computing.This paper provides comprehensive overview of flexible memristors from perspectives of development history,material system,device structure,mechanical deformation method,device performance analysis,stress simulation during deformation,and neuromorphic computing applications.The recent advances in flexible electronics are summarized,including single device,device array and integration.The challenges and future perspectives of flexible memristor for neuromorphic computing are discussed deeply,paving the way for constructing wearable smart electronics and applications in large-scale neuromorphic computing and high-order intelligent robotics.
基金supported by Youth Talent Project of Scientific Research Program of Hubei Provincial Department of Education under Grant Q20241809Doctoral Scientific Research Foundation of Hubei University of Automotive Technology under Grant 202404.
文摘As Internet of Things(IoT)applications expand,Mobile Edge Computing(MEC)has emerged as a promising architecture to overcome the real-time processing limitations of mobile devices.Edge-side computation offloading plays a pivotal role in MEC performance but remains challenging due to complex task topologies,conflicting objectives,and limited resources.This paper addresses high-dimensional multi-objective offloading for serial heterogeneous tasks in MEC.We jointly consider task heterogeneity,high-dimensional objectives,and flexible resource scheduling,modeling the problem as a Many-objective optimization.To solve it,we propose a flexible framework integrating an improved cooperative co-evolutionary algorithm based on decomposition(MOCC/D)and a flexible scheduling strategy.Experimental results on benchmark functions and simulation scenarios show that the proposed method outperforms existing approaches in both convergence and solution quality.
基金Open access funding provided by FCT|FCCN(b-on)the Strategic Research Plan of the Centre for Marine Technology and Ocean Engineering(CENTEC),which is financed by the Portuguese Foundation for Science and Technology(Fundação para a Ciência e Tecnologia-FCT)under contract UIDB/UIDP/00134/2020.
文摘An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.
基金supported by the National Natural Science Foundation of China(No.52375443)the Innovative Research Group Project of the National Natural Science Foundation of China(No.51921003)。
文摘To meet the demand for the machining of blisks with narrow cascade channels and twisted blade profiles,especially integral shrouded blisks with shrouds,this paper innovatively proposes a method for dynamic deformation electrochemical cutting of flexible electrodes with arrayed group slit structure.By applying torque to both ends of the flexible electrode,the proposed method produces bending deformation and realizes the processing of a twisted profile.The flexible electrode is an important carrier of this method,and its properties such as elasticity,rigidity,and flow field uniformity have a crucial impact on smooth processing.Therefore,this paper proposes a design theory of flexible electrodes with an arrayed group slit structure and designs flexible electrodes with variable cross-sections.Compared with traditional uniform section tube electrode,the designed flexible electrode was subjected to the corresponding mechanical simulation,flow field simulation,and fluid–structure interaction simulation to investigate the elasticity,rigidity,and flow field uniformity of the flexible electrode.In addition,a deformation device of flexible electrodes was constructed and the corresponding experiments were carried out.Simulations and experiments demonstrate that flexible electrodes with arrayed group slit structures have good comprehensive performance.Finally,typical components were successfully machined to verify the feasibility of the proposed method and the rationality of the designed flexible electrode.It is shown that the proposed method has great potential for the machining of distorted profiles and provides a new idea for the machining of complex profiles.
基金financially supported by the National Natural Science Foundation of China (No.51503158)Key R&D Program of Hubei Province (No.2023BAB104)Open Project Program of High-Tech Organic Fibers Key Laboratory of Sichuan Province(No.PLN2024-08)
文摘The phenomena of thermal runaway and accidental deformation due to external stresses in lithium batteries or film capacitors consti-tute their primary failure mechanisms.Therefore,monitoring and early warning of overheating or localized strain are of great value for the safe use of lithium batteries or film capacitors;however,this function usually requires a system of multiple complex sensors.The realization of the above multiple hazards using a single sensor for monitoring and alarm functions has not been reported.Here,we exploit the thermally induced conductivity and modulus change during solid-liquid conversion of low melting point polyalloys to modulate the electronic relaxation polariza-tion and interfacial polarization in the composites for dielectric switching,and the reduction of alloy particle spacing during bending/compres-sive strain can be used to generate switchable tunneling effects for insulator-conductor transition.By synergizing dielectric switching and insula-tor-conductor transition,the final flexible thermoplastic polyurethane elastomer/low-melting-point polyalloy composite film achieves the func-tional integration of multi-level overheating warning and small deformation monitoring.
文摘In this study, the results of 1-g shaking table tests performed on small-scale flexible cantilever wallmodels retaining composite backfill made of a deformable geofoam inclusion and granular cohesionlessmaterial were presented. Two different polystyrene materials were utilized as deformable inclusions.Lateral dynamic earth pressures and wall displacements at different elevations of the retaining wallmodel were monitored during the tests. The earth pressures and displacements of the retaining wallswith deformable inclusions were compared with those of the models without geofoam inclusions.Comparisons indicated that geofoam panels of low stiffness installed against the retaining wall modelaffect displacement and dynamic lateral pressure profile along the wall height. Depending on the inclusioncharacteristics and the wall flexibility, up to 50% reduction in dynamic earth pressures wasobserved. The efficiency of load and displacement reduction decreased as the flexibility ratio of the wallmodel increased. On the other hand, dynamic load reduction efficiency of the deformable inclusionincreased as the amplitude and frequency ratio of the seismic excitation increased. Relative flexibility ofthe deformable layer （the thickness and the elastic stiffness of the polystyrene material） played animportant role in the amount of load reduction. Dynamic earth pressure coefficients were compared withthose calculated with an analytical approach. Pressure coefficients calculated with this method werefound to be in good agreement with the results of the tests performed on the wall model having lowflexibility ratio. It was observed that deformable inclusions reduce residual wall stresses observed at theend of seismic excitation thus contributing to the post-earthquake stability of the retaining wall. Thegraphs presented within this paper regarding the dynamic earth pressure coefficients versus the wallflexibility and inclusion characteristics may serve for the seismic design of full-scale retaining walls withdeformable polystyrene inclusions. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.
文摘As human aeronautic and aerospace technology continues to prosper and the aerial flight space domain further expands,traditional fixed-shape air vehicles have been confronted with difficulties in satisfying complex missions in cross-domain scenarios.Owing to their flexible and deformable appearance,morphing air vehicles are expected to realize cross-domain intelligent flight,thus emerging as the most subversive strategic development trend and research focus in aeronautic and aerospace fields.This paper primarily reviews the research background and challenges of flexible and deformable cross-domain intelligent flight,proposing a corresponding research framework and mode as well as exploring the scientific issues and state-of-the-art solutions,where key research progress is introduced.The explorations covered in this paper also provide ideas and directions for the study of deformable cross-domain intelligent flight,which has critical scientific significance in promoting the study itself.
基金supported by Scientific and technological breakthroughs in Henan Province (No.222102220101), (No.212102210067)National natural science foundation of China (Grant No.52075500).
文摘This work presents a novel highly adaptable flexible soft glove composed of multimode deformable three-jointed soft fingers.The soft fingers are assembled by soft actuators and plastic materials that can be driven and controlled with single Degree of Freedom(DOF).A variety of different soft actuators are used as joint drive components to meet the motion requirements of fingers under different working conditions.We established a theoretical model to describe the deflection of the soft actuators based on reciprocal theorems.In addition,the finite-element method(FEM)was used to simulate the curvature change of the soft actuator and the soft finger,the soft actuators theoretical and simulation results were verified by experiments,and the multimode deformable soft fingers were simulated by FEM.Finally,a five-finger soft rehabilitation glove was prototyped and presented experimentally where the flexibility and functionality endowed by the soft fingers were demonstrated and highlighted.The versatility was also showcased in the applications.
基金supported by the National Key R&D Plan of China(Grant No.2023YFB3210400)the National Natural Science Foundation of China(No.62174101)+2 种基金the Major Scientific and Technological Innovation Project of Shandong Province(2021CXGC010603)the Fundamental Research Funds of Shandong University(2020QNQT001)Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong,Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong,the Natural Science Foundation of Qingdao-Original exploration project(No.24-4-4-zrjj-139-jch).
文摘Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabrication,low-power consumption,fast response times,and versatility.Graphene,known for its exceptional mechanical properties,high electron mobility,and biocompatibility,is an ideal material for FET channels and sensors.The combination of graphene and FETs has given rise to flexible graphene field-effect transistors(FGFETs),driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors.Here,we first provide a brief overview of the basic structure,operating mechanism,and evaluation parameters of FGFETs,and delve into their material selection and patterning techniques.The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities.We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors,focusing on the key aspects of constructing high-quality flexible biomedical sensors.Finally,we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors.This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing.
基金funded by the National Natural Science Foundation of China(52475580)the Special Foundation of the Taishan Scholar Project(tsqn202211077,tsqn202311077)+3 种基金Shandong Provincial Excellent Overseas Young Scholar Foundation(2023HWYQ-069)the Shandong Provincial Natural Science Foundation(ZR2023ME118,ZR2023QF080)the Natural Science Foundation of Qingdao City(23-2-1-219-zyyd-jch,23-2-1-111-zyyd-jch)the Fundamental Research Funds for the Central Universities(23CX06032A).
文摘The complex wiring,bulky data collection devices,and difficulty in fast and on-site data interpretation significantly limit the practical application of flexible strain sensors as wearable devices.To tackle these challenges,this work develops an artificial intelligenceassisted,wireless,flexible,and wearable mechanoluminescent strain sensor system(AIFWMLS)by integration of deep learning neural network-based color data processing system(CDPS)with a sandwich-structured flexible mechanoluminescent sensor(SFLC)film.The SFLC film shows remarkable and robust mechanoluminescent performance with a simple structure for easy fabrication.The CDPS system can rapidly and accurately extract and interpret the color of the SFLC film to strain values with auto-correction of errors caused by the varying color temperature,which significantly improves the accuracy of the predicted strain.A smart glove mechanoluminescent sensor system demonstrates the great potential of the AIFWMLS system in human gesture recognition.Moreover,the versatile SFLC film can also serve as a encryption device.The integration of deep learning neural network-based artificial intelligence and SFLC film provides a promising strategy to break the“color to strain value”bottleneck that hinders the practical application of flexible colorimetric strain sensors,which could promote the development of wearable and flexible strain sensors from laboratory research to consumer markets.
基金The project supported by the National Natural Science Foundation of China(10472066,10372057)The English text was polished by Yunming Chen.
文摘In this paper, nonlinear modeling for flexible multibody system with large deformation is investigated. Absolute nodal coordinates are employed to describe the displacement, and variational motion equations of a flexible body are derived on the basis of the geometric nonlinear theory, in which both the shear strain and the transverse normal strain are taken into account. By separating the inner and the boundary nodal coordinates, the motion equations of a flexible multibody system are assembled. The advantage of such formulation is that the constraint equations and the forward recursive equations become linear because the absolute nodal coordinates are used. A spatial double pendulum connected to the ground with a spherical joint is simulated to investigate the dynamic performance of flexible beams with large deformation. Finally, the resultant constant total energy validates the present formulation.
基金Ordinary University Graduate Student Research Innovation Projects of Jiangsu Province(No.CXZZ12 0177)the National Natural Science Foundation of China(No.61304137)
文摘In this paper, the substructuring technique is extended for the dynamics simulation of flexible beams with large deformation. The dynamics equation of a spatial straight beam undergoing large displacement and small deformation is deduced by using the Jourdain variation principle and the model synthesis method. The longitudinal shortening effect due to the transversal deformation is taken into consideration in the dynamics equation. In this way, the geometric stiffening effect, which is also called stress stiffening effect, is accounted for in the dynamics equation. The transfer equation of the flexible beam is obtained by assembling the dynamics equation and the kinematic relationship between the two connection points of the flexible beam. Treating a flexible beam with small deformation as a substructure, one can solve the dynamics of a flexible beam with large deformation by using the substructuring technique and the transfer matrix method. The dynamics simulation of a flexible beam with large deformation is carried out by using the proposed approach and the results are verified by comparing with those obtained from Abaqus software.
基金support given by the National Natural Science Foundation of China(No.51275202)
文摘The flexible rolling process(FRP) is a novel three-dimensional(3 D) forming process that combines the multipoint and traditional rolling forming. The principle of FRP is based on thickness thinning, so the deformation path significantly impacts the forming effect. In this study, the multistep forming process with different deformation paths was introduced to improve the forming effect of FRP. For instance, with the convex surface part, three finite element models of multistep FRP(MSFRP) were established. The corresponding numerical simulations and forming experiments performed among different deformation paths showed the surface part with a longer effective forming region was obtained and the forming regions with more steps in MSFRP were smoother. Thus, the sheet-metal utilization rate was greatly improved. Moreover, the MSFRP can improve the longitudinal bending effect dramatically and thereby endowing the forming part with a better forming effect. Therefore, MSFRP is a prospective method for broad applications.
基金Project 2004GG3204001 supported by the Science and Technology Development Plan of Shandong Province
文摘The flexible inner pressure bolt is a new kind and new structural bolt (anchor rod). A number of structural improvements and performance test have been carried out. The bolt has superior compatibility to the soft crag and the large distortion tunnel with its flexibility. In order to study its stress, deformation and interaction mechanism thoroughly, a number of large distortion calcula- tions and analyses have been carried out on the bolt by FEM (finite element method), especially with the ANSYS software, based on the updated Lagrangian law. The results show that the maximum stress of the inner wall of the bolt is consistent with an elastic analytic solution. The maximum stress on the body occurs in the vicinity of the enhancement material. The link enhancement of the body seems to be quite essential. The experimental results indicate that the maximum injection pressure in the bolt is 2.5 MPa without link enhancement and 8.3 MPa with the enhancement. This link enhancement effect is highly significant. These results provide some basis for the design, application and anchoring stress analysis of the bolt.
基金the National Natural Science Foundation of China(Nos.11902017 and 11672022).
文摘The Flapping Rotary Wing(FRW)is a micro air vehicle wing layout coupling flapping,pitching,and rotating motions.It can gain bencfits in high lift from a fast passive rotating motion,which is tightly related to the passive pitching motion directly caused by wing flexible deformation.Therefore,flexible deformation is crucial for the wing kinematics and aerodynamic performance of an FRW.In this paper,we explored the effct of flexibility on wing kinematics and acrodynamics on the basis of a mechanical FRW model.A photogrammetric method was adopted to capture motion images according to which wing orientations and deformations were reconstructed.Corresponding acrodynamic force was computed using computational fluid dynamic method,and wing kinematics and deformations were used as simulation inputs.The experimental measurements presented the real orientation and deformation pattem of a real FRW.The wing passive deformation of a high-intensity FRW was found to be mainly caused by inertial force,and a linear positive spanwise twist was observed in the FRW.The effects of wing deformation on aerodynamic force production and the underlying mechanism were addressed.Results showed that lift augment,rotating moment enhancement,and power efficiency improvement can be achieved when a wing becomes flexible.Wing spanwise twist mainly accounts for these changes in aerodynamics,and increment in spanwise twist could further contributes to aerodynamic improvement.
基金supported by the National Natural Science Foundation of China(Grant No.52275304 and 51975014).
文摘T-joint titanium alloy structures are commonly used in aircraft manufacturing,and their laser welding process is relatively mature,but due to the strict requirements of the airplane production,the angular deformation caused by uneven heat input across the sheet is still not negligible,so active control needs to be imposed.In this paper,an active deformation control method based on programmable multi-point flexible support is proposed and validated.In response to the problem that the traditional rigid clamping and pre-stressing are not adapted to the T-structure thin sheet,this study has designed a multi-point flexible support with microcontroller and electric actuators,which can monitor the stress state of the current support position in real time during the welding process and make dynamic adjustment,so that the weld deformation could be effectively reduced in this way.
文摘Electrospinning technology has emerged as a promising method for fabricating flexible lithium-ion batter-ies(FLIBs)due to its ability to create materials with desir-able properties for energy storage applications.FLIBs,which are foldable and have high energy densities,are be-coming increasingly important as power sources for wear-able devices,flexible electronics,and mobile energy applica-tions.Carbon materials,especially carbon nanofibers,are pivotal in improving the performance of FLIBs by increas-ing electrical conductivity,chemical stability,and surface area,as well as reducing costs.These materials also play a significant role in establishing conducting networks and im-proving structural integrity,which are essential for extend-ing the cycle life and enhancing the safety of the batteries.This review considers the role of electrospinning in the fabrication of critical FLIB components,with a particular emphasis on the integration of carbon materials.It explores strategies to optimize FLIB performance by fine-tuning the electrospinning para-meters,such as electric field strength,spinning rate,solution concentration,and carbonization process.Precise control over fiber properties is crucial for enhancing battery reliability and stability during folding and bending.It also highlights the latest research findings in carbon-based electrode materials,high-performance electrolytes,and separator structures,discussing the practical challenges and opportunities these materials present.It underscores the significant impact of carbon materials on the evolution of FLIBs and their potential to shape future energy storage technologies.
文摘Photodetectors with weak-light detection capabilities play an indispensable role in various crucial fields such as health monitors,imaging,optical communication,and etc.Nevertheless,the detection of weak light signals is often severely interfered by multiple factors such as background light,dark noise and circuit noise,making it difficult to accurately capture signals.While traditional technologies like silicon photomultiplier tubes excel in sensitivity,their high cost and inherent fragility restrict their widespread application.Against this background,perovskite materials have rapidly emerged as a research focus in the field of photodetection due to their simple preparation processes and exceptional optoelectronic properties.Not only are the preparation processes of perovskite materials straightforward and cost-effective,but more importantly,they can be flexibly integrated into flexible and stretchable substrates.This characteristic significantly compensates for the shortcomings of traditional rigid electronic devices in specific application scenarios,opening up entirely new possibilities for photodetection technology.Herein,recent advances in perovskite light detection technology are reviewed.Firstly,the chemical and physical properties of perovskite materials are discussed,highlighting their remarkable advantages in weak-light detection.Subsequently,the review systematically organizes various preparation techniques of perovskite materials and analyses their advantages in different application scenarios.Meanwhile,from the two core dimensions of performance improvement and light absorption enhancement,the key strategies of improving the performance of perovskite weak-light photodetectors are explored.Finally,the review concludes with a brief summary and a discussion on the potential challenges that may arise in the further development of perovskite devices.
