Traditional dynamic analysis of mechanical structures,often limited to individual beams or plates,fails to fully capture their dynamic behaviors.In systems where space and mass are constrained,such as the battery supp...Traditional dynamic analysis of mechanical structures,often limited to individual beams or plates,fails to fully capture their dynamic behaviors.In systems where space and mass are constrained,such as the battery support structures in electric aircraft,conventional absorbers and isolators are insufficient for effective vibration control.This study simplifies the battery support structure of electric aircraft as an integrated composite beam consisting of three interconnected beams,and investigated its structural dynamics properties and nonlinear vibration control under thermal conditions caused by battery heat.The nonlinear vibration control is performed using the Nitinol steel wire ropes(Ni Ti-ST),with nonlinear damping properties.The natural frequencies of system are determined using the Rayleigh-Ritz technique.Theoretical results are validated through both Finite Element Method(FEM)and hammer tests.Moreover,the dynamic equations are derived using the Lagrange method and discretized via the Galerkin Truncation Method(GTM).The Harmonic Balance Method(HBM)is used to evaluate the vibration responses of the integrated model,with further verification through the Runge-Kutta Method(RKM).The experiments are conducted to corroborate the theoretical analysis.The results show that the system frequency changes in stages with the increase of the stiffness of the integrated composite beam connection.Especially in the case of varying environments,as the temperature increases,the frequency of system will first increase to a certain maximum value and then gradually decrease.Furthermore,the NiTi-ST effectively reduces vibration in the integrated composite beam,particularly under varying temperatures and external excitations.展开更多
Accurate boundary conditions of composite material plates with different holes are founded to settle boundary condition problems of complex holes by conformal mapping method upon the nonhomogeneous anisotropic elastic...Accurate boundary conditions of composite material plates with different holes are founded to settle boundary condition problems of complex holes by conformal mapping method upon the nonhomogeneous anisotropic elastic and complex function theory. And then the two stress functions required were founded on Cauchy integral by boundary conditions. The final stress distributions of opening structure and the analytical solution on composite material plate with rectangle hole and wing manholes were achieved. The influences on hole-edge stress concentration factors are discussed under different loads and fiber direction cases, and then contrast calculates are carried through FEM.展开更多
This study investigates the low-velocity impact and post-impact flexural properties of 3D integrated woven spacer composites,focusing on their orthotropic behavior when tested along two principal directions,i.e.,warp(...This study investigates the low-velocity impact and post-impact flexural properties of 3D integrated woven spacer composites,focusing on their orthotropic behavior when tested along two principal directions,i.e.,warp(X-type)and weft(Y-type)directions.The same composite material was tested in these orientations to evaluate the differences in impact resistance and residual bending strength.Specimens were fabricated via vacuum-assisted molding and tested at 2,3,5,and 7 J impact energies using an Instron Ceast 9350 drop-weight impact testing machine,in accordance with ASTM D7136.Post-impact flexural tests were performed using a four-point bending method in accordance with ASTM D7264.The absorbed energy increased from 1.97 to 6.98 J,and the panel damage area ranged from 121 to 361 mm^(2) as impact energy roses.Specimens tested in the weft direction(Y-type)showed greater residual strength(up to 15.83 N)and displacement(up to 0.538 mm)than those tested in the warp direction(X-type).Ultrasonic C-scan imaging revealed localized matrix cracking and fiber failure damage patterns.Results emphasize the directional differences in impact resistance and residual bending properties,highlighting the importance of material orientation in structural applications.This study provides a foundation for utilizing 3D woven spacer composites in lightweight,damage-tolerant structural components.展开更多
Nowadays fuzzy concepts are frequently used as statistical parameters, while the traditional normal distribution can only accept determinate variable. In order to design a practical model for fuzzy statistic events, t...Nowadays fuzzy concepts are frequently used as statistical parameters, while the traditional normal distribution can only accept determinate variable. In order to design a practical model for fuzzy statistic events, this paper combines the fuzzy number, like “may-occur”, “very-likely-occur”, “rarely-occur”, to optimize the normal distribution probability density function, to provide a significant method in statistics.展开更多
A bandwidth microwave second harmonic generator is successfully designed using composite right/left-handed non- linear transmission lines （CRLH NLTLs） in a GaAs monolithic microwave integrated circuit （MMIC） techn...A bandwidth microwave second harmonic generator is successfully designed using composite right/left-handed non- linear transmission lines （CRLH NLTLs） in a GaAs monolithic microwave integrated circuit （MMIC） technology. The structure parameters of CRLH NLTLs, e.g. host transmission line, rectangular spiral inductor, and nonlinear capacitor, have a great impact on the second harmonic performance enhancement in terms of second harmonic frequency, output power, and conversion efficiency. It has been experimentally demonstrated that the second harmonic frequency is deter- mined by the anomalous dispersion of CRLH NLTLs and can be significantly improved by effectively adjusting these structure parameters. A good agreement between the measured and simulated second harmonic performances of Ka-band CRLH NLTLs frequency multipliers is successfully achieved, which further validates the design approach of frequency multipliers on CRLH NLTLs and indicates the potentials of CRLH NLTLs in terms of the generation of microwave and millimeter-wave signal source.展开更多
Silicon-based material is considered to be one of the most promising anodes for the next-generation lithium-ion batteries(LIBs)due to its rich sources,nontoxicity,low cost and high theoretical specific capacity.Howeve...Silicon-based material is considered to be one of the most promising anodes for the next-generation lithium-ion batteries(LIBs)due to its rich sources,nontoxicity,low cost and high theoretical specific capacity.However,it cannot maintain a stable electrode structure during repeated charge/discharge cycles,and therefore long cycling life is difficult to be achieved.To address this problem,herein a simple and efficient method is developed for the fabrication of an integrated composite anode consisting of SiO-based active material and current collector,which exhibits a core-shell structure with nitrogen-doped carbon coating on SiO/P micro-particles.Without binder and conductive agent,the volume expansion of SiO active material in the integrated composite anode is suppressed to prevent its pulverization.At a current density of 500 mA·g−1,this integrated composite anode exhibits a reversible specific capacity of 458 mA·h·g−1 after 200 cycles.Furthermore,superior rate performance and cycling stability are also achieved.This work illustrates a potential method for the fabrication of integrated composite anodes with superior electrochemical properties for high-performance LIBs.展开更多
This review analyzes the state and recent progress in the field of information support for pollen allergy sufferers.For decades,information available for the patients and allergologists consisted of pollen counts,whic...This review analyzes the state and recent progress in the field of information support for pollen allergy sufferers.For decades,information available for the patients and allergologists consisted of pollen counts,which are vital but insufficient.New technology paves the way to substantial increase in amount and diversity of the data.This paper reviews old and newly suggested methods to predict pollen and air pollutant concentrations in the air and proposes an allergy risk concept,which combines the pollen and pollution information and transforms it into a qualitative risk index.This new index is available in an app(Mobile Airways Sentinel NetworK-air)that was developed in the frame of the European Union grant Impact of Air POLLution on sleep,Asthma and Rhinitis(a project of European Institute of Innovation and Technology-Health).On-going transformation of the pollen allergy information support is based on new technological solutions for pollen and air quality monitoring and predictions.The new information-technology and artificial-intelligence-based solutions help to convert this information into easy-to-use services for both medical practitioners and allergy sufferers.展开更多
基金supported by the National Natural Science Foundation of China(No.12272240)the Liaoning Revitalization Talents Program,China(No.XLYC2203197)。
文摘Traditional dynamic analysis of mechanical structures,often limited to individual beams or plates,fails to fully capture their dynamic behaviors.In systems where space and mass are constrained,such as the battery support structures in electric aircraft,conventional absorbers and isolators are insufficient for effective vibration control.This study simplifies the battery support structure of electric aircraft as an integrated composite beam consisting of three interconnected beams,and investigated its structural dynamics properties and nonlinear vibration control under thermal conditions caused by battery heat.The nonlinear vibration control is performed using the Nitinol steel wire ropes(Ni Ti-ST),with nonlinear damping properties.The natural frequencies of system are determined using the Rayleigh-Ritz technique.Theoretical results are validated through both Finite Element Method(FEM)and hammer tests.Moreover,the dynamic equations are derived using the Lagrange method and discretized via the Galerkin Truncation Method(GTM).The Harmonic Balance Method(HBM)is used to evaluate the vibration responses of the integrated model,with further verification through the Runge-Kutta Method(RKM).The experiments are conducted to corroborate the theoretical analysis.The results show that the system frequency changes in stages with the increase of the stiffness of the integrated composite beam connection.Especially in the case of varying environments,as the temperature increases,the frequency of system will first increase to a certain maximum value and then gradually decrease.Furthermore,the NiTi-ST effectively reduces vibration in the integrated composite beam,particularly under varying temperatures and external excitations.
基金This project is supported by National Natural Science Foundation of China(No.50175031).
文摘Accurate boundary conditions of composite material plates with different holes are founded to settle boundary condition problems of complex holes by conformal mapping method upon the nonhomogeneous anisotropic elastic and complex function theory. And then the two stress functions required were founded on Cauchy integral by boundary conditions. The final stress distributions of opening structure and the analytical solution on composite material plate with rectangle hole and wing manholes were achieved. The influences on hole-edge stress concentration factors are discussed under different loads and fiber direction cases, and then contrast calculates are carried through FEM.
基金funded by Open Foundation of the State Key Laboratory of Advanced Inorganic Fibers and Composites(Grant No.KF2024SYS02)the Jiangsu Province Special Fund for Carbon Peaking and Carbon Neutrality Technology Innovation(Grant No.BE2022008)the Prioritized Academic Program Development for Higher Education Institutions in Jiangsu.
文摘This study investigates the low-velocity impact and post-impact flexural properties of 3D integrated woven spacer composites,focusing on their orthotropic behavior when tested along two principal directions,i.e.,warp(X-type)and weft(Y-type)directions.The same composite material was tested in these orientations to evaluate the differences in impact resistance and residual bending strength.Specimens were fabricated via vacuum-assisted molding and tested at 2,3,5,and 7 J impact energies using an Instron Ceast 9350 drop-weight impact testing machine,in accordance with ASTM D7136.Post-impact flexural tests were performed using a four-point bending method in accordance with ASTM D7264.The absorbed energy increased from 1.97 to 6.98 J,and the panel damage area ranged from 121 to 361 mm^(2) as impact energy roses.Specimens tested in the weft direction(Y-type)showed greater residual strength(up to 15.83 N)and displacement(up to 0.538 mm)than those tested in the warp direction(X-type).Ultrasonic C-scan imaging revealed localized matrix cracking and fiber failure damage patterns.Results emphasize the directional differences in impact resistance and residual bending properties,highlighting the importance of material orientation in structural applications.This study provides a foundation for utilizing 3D woven spacer composites in lightweight,damage-tolerant structural components.
文摘Nowadays fuzzy concepts are frequently used as statistical parameters, while the traditional normal distribution can only accept determinate variable. In order to design a practical model for fuzzy statistic events, this paper combines the fuzzy number, like “may-occur”, “very-likely-occur”, “rarely-occur”, to optimize the normal distribution probability density function, to provide a significant method in statistics.
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.61401373)the Research Fund for the Doctoral Program of Southwest University,China(Grant No.SWU111030)
文摘A bandwidth microwave second harmonic generator is successfully designed using composite right/left-handed non- linear transmission lines （CRLH NLTLs） in a GaAs monolithic microwave integrated circuit （MMIC） technology. The structure parameters of CRLH NLTLs, e.g. host transmission line, rectangular spiral inductor, and nonlinear capacitor, have a great impact on the second harmonic performance enhancement in terms of second harmonic frequency, output power, and conversion efficiency. It has been experimentally demonstrated that the second harmonic frequency is deter- mined by the anomalous dispersion of CRLH NLTLs and can be significantly improved by effectively adjusting these structure parameters. A good agreement between the measured and simulated second harmonic performances of Ka-band CRLH NLTLs frequency multipliers is successfully achieved, which further validates the design approach of frequency multipliers on CRLH NLTLs and indicates the potentials of CRLH NLTLs in terms of the generation of microwave and millimeter-wave signal source.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 21965007, 51671062 and 51871065)the Guangxi Natural Science Foundation (Grant No. 2018GXNSFFA281005)+2 种基金the Chinesisch-Deutsche Kooperationsgruppe (Grant No. GZ1528)the Innovation Project of GUET Graduate Education (Grant Nos. 2019YCXS115 and 2019YCXS111)the Guangxi Bagui Scholar Foundation, Guangxi Advanced Functional Materials Foundation and Application Talents Small Highlands.
文摘Silicon-based material is considered to be one of the most promising anodes for the next-generation lithium-ion batteries(LIBs)due to its rich sources,nontoxicity,low cost and high theoretical specific capacity.However,it cannot maintain a stable electrode structure during repeated charge/discharge cycles,and therefore long cycling life is difficult to be achieved.To address this problem,herein a simple and efficient method is developed for the fabrication of an integrated composite anode consisting of SiO-based active material and current collector,which exhibits a core-shell structure with nitrogen-doped carbon coating on SiO/P micro-particles.Without binder and conductive agent,the volume expansion of SiO active material in the integrated composite anode is suppressed to prevent its pulverization.At a current density of 500 mA·g−1,this integrated composite anode exhibits a reversible specific capacity of 458 mA·h·g−1 after 200 cycles.Furthermore,superior rate performance and cycling stability are also achieved.This work illustrates a potential method for the fabrication of integrated composite anodes with superior electrochemical properties for high-performance LIBs.
文摘This review analyzes the state and recent progress in the field of information support for pollen allergy sufferers.For decades,information available for the patients and allergologists consisted of pollen counts,which are vital but insufficient.New technology paves the way to substantial increase in amount and diversity of the data.This paper reviews old and newly suggested methods to predict pollen and air pollutant concentrations in the air and proposes an allergy risk concept,which combines the pollen and pollution information and transforms it into a qualitative risk index.This new index is available in an app(Mobile Airways Sentinel NetworK-air)that was developed in the frame of the European Union grant Impact of Air POLLution on sleep,Asthma and Rhinitis(a project of European Institute of Innovation and Technology-Health).On-going transformation of the pollen allergy information support is based on new technological solutions for pollen and air quality monitoring and predictions.The new information-technology and artificial-intelligence-based solutions help to convert this information into easy-to-use services for both medical practitioners and allergy sufferers.
