In this paper,an experimental study of an air inflated membrane was carried out based on the China National Stadium (the Bird's Nest). After the 2008 Olympic Games,it was apparent that the future use of the Bird&#...In this paper,an experimental study of an air inflated membrane was carried out based on the China National Stadium (the Bird's Nest). After the 2008 Olympic Games,it was apparent that the future use of the Bird's Nest would be enhanced if rainfall could be prevented from entering the stadium. The installation of an air inflated membrane across the opening of the steel structure was proposed as a solution to this problem. To verify the scheme,a theoretical analysis and experimental study of an air inflated membrane was carried out. Experimental and computational models were developed,form-finding was carried out using both experimental and theoretical methods,and the results from the two approaches,including the deflection of the air inflated membrane and deformation of the support structure,were analyzed and compared. The force-transfer path and deformation of the air inflated membrane under loads was studied. Conclusions and suggestions are presented.展开更多
This paper proposes a frequency reconfigurable triangular antenna actuated by an inflated triangular structure.The open path antenna is transformed from an open type to a closed structure by inflating.Inflatable struc...This paper proposes a frequency reconfigurable triangular antenna actuated by an inflated triangular structure.The open path antenna is transformed from an open type to a closed structure by inflating.Inflatable structures are easy to manufacture by fusing 2 inextensible membranes together along a defined pattern of lines.However,the prediction of their deployed shape remains a challenge.To solve the pattern changed problem,guided by geometric analyses and local buckle characteristics,the inflated triangular structure has been designed and verified by experiment and simulation.In the process of transformation of the antenna,the resonant frequency of the antenna is changed because this frequency is determined by the conformational change.The resonant frequency changes from GHz to kHz when the design of initial structure sizes is from millimeter to meter.The measured peak gains,the frequency,and the radiation direction are also reconfigurable by the initial size.Finally,the reconfigurable resonator array is presented,which is coupled to electric fields to absorb all incident radiation.In this work,the changed pattern design by inflating is applied to the antenna design,and its frequency reconfigurability is achieved.Through the electricity performance analysis of the reconfigurable antenna,precise manufacturing will be possible and provide guidance for manufacturing frequency reconfigurable antennas.展开更多
The bending stiffness of the inflated beam is considered as a constant before wrinkles appear, and it decreases obviously as wrinkles propagate. The formula of the bending stiffness is obtained based on the membrane t...The bending stiffness of the inflated beam is considered as a constant before wrinkles appear, and it decreases obviously as wrinkles propagate. The formula of the bending stiffness is obtained based on the membrane theory in this paper. Furthermore, the definition of dimensionless bending stiffness factor is presented; the relationship of bending stiffness factor and wrinkling factor is derived; the bending stiffness factor is simplified as different linear functions with wrinkling factor, and the simplified model of bending stiffness of inflated beam under bending is also obtained. The bending stiffness including expression of wrinkling factor is substituted into the deflection differential equation, and then the slope and deflection equation of the inflated beam is deduced by integrating the deflection differential equation. Finally, the load-deflection curve is obtained, which is compared with the experimental data in a previous paper. It has a good agreement with each other.展开更多
China National Stadium,also known as "Bird's Nest",is the main stadium of the 29th Olympic Games in Beijing in 2008,which has successfully held not only the Opening and the Closing ceremonies but also th...China National Stadium,also known as "Bird's Nest",is the main stadium of the 29th Olympic Games in Beijing in 2008,which has successfully held not only the Opening and the Closing ceremonies but also the track and field events.A new problem of rain preventing is brought out to improve the utilization of the Bird's Nest after the Olympic Games.The scheme of installing an air inflated membrane at the opening of the steel structure is proposed in this paper to solve the rainproof problem of the Bird's Nest.The form-finding and mechanical analyses of the air inflated membrane are carried out.Comparison between the mechanical performance and dynamical character before and after installing the air inflated membrane structure is given.To verify the analysis results,based on the practical structure of the Bird's Nest,a test of a 1:20 model membrane is worked out.展开更多
A new model is proposed to accurately predict the wrinkling and collapse loads of a membrane inflated beam. In this model, the pressure effects are considered and a modified factor is introduced to obtain an accurate ...A new model is proposed to accurately predict the wrinkling and collapse loads of a membrane inflated beam. In this model, the pressure effects are considered and a modified factor is introduced to obtain an accurate prediction. The former is achieved by modifying the pressure-related structural parameters based on elastic small strain considerations, and the modified factor is determined by our test data. Compared with previous models and our test data, the present model, named as shell-membrane model, can accurately predict the wrinkling and collapse loads of membrane inflated beams.展开更多
A floating air weapon system(such as airborne floating mines)plays an important role in modern air defense operations.This paper focuses on aeroelastic characteristics of airborne floating mine named inflated pillow.F...A floating air weapon system(such as airborne floating mines)plays an important role in modern air defense operations.This paper focuses on aeroelastic characteristics of airborne floating mine named inflated pillow.Firstly,the dynamic deployable process of the pillow and characteristics of the local instability of the edge are studied,and the evolution mechanism of wrinkles and kinks is analyzed.Secondly,in the cruising stage,the fluid-structural-thermal coupling analysis is performed on the pillow,and the aeroelastic characteristics are studied.Thirdly,the shapepreserving effect of the inflated pillow during the“negative pressure”slow landing stage is evaluated.It is found that when the wind velocity is higher,the pillow has a collapsed instability(surface extrusion and contact),and when the wind velocity is lower,snap-through instability occurs.Finally,for the collapsed instability,a carbon fiber skeleton is added to discrete the large global collapsed fold into small local folds,thus achieving shape-preserving effect of pillow.For snapthrough instability,the critical internal pressure and different shape evolution under different wind velocity are evaluated.Through the analysis of the mechanical mechanism and control of the structural morphological evolution,it provides theoretical guidance for the application of the curved shell structure in floating air weapon system.展开更多
The present paper studies the contact problem of an inflated toroidal nonlinear anisotropic hyperelastic membrane laterally pressed between two flat rigid plates.The material is assumed to be homogeneous,and an anisot...The present paper studies the contact problem of an inflated toroidal nonlinear anisotropic hyperelastic membrane laterally pressed between two flat rigid plates.The material is assumed to be homogeneous,and an anisotropic term is included in the incompressible Mooney–Rivlin hyperelastic model.Initially,two annular-shaped flat membranes,bonded at both equators,are considered in an undeformed state,which results in a toroidal geometry upon uniform internal pressurization.The contact problem of the inflated torus laterally pressed between two flat parallel plates is solved.Two different contact conditions,namely frictionless contact and no-slip contact,are considered within the contact region.The enclosed amount of gas within the inflated membrane is considered to be constant during the solution of the contact problem,which is solved in a quasi-static manner.In the case of no-slip contact,the stretch locking has been observed,and the frictionless contact causes the free flow of material points.The membrane’s stiffness increases with increasing anisotropic,material,and geometric parameters depicted in the force versus displacement curve under contact conditions.展开更多
The fluid-structure interaction (FSI) between the canopy and flow field on the inflating and inflated conditions is investigated based on the arbitrary Lagrange-Euler (ALE) method,in both a single-and double-cruciform...The fluid-structure interaction (FSI) between the canopy and flow field on the inflating and inflated conditions is investigated based on the arbitrary Lagrange-Euler (ALE) method,in both a single-and double-cruciform parachute systems.The projection area of canopy is calculated in the inflation process.The flow field characteristics and the interaction between canopies are analyzed.Results showed that,with free stream velocity of 50m/s,overinflation phenomenon would not occur during the inflation process of the double-cruciform-parachute system,because the collision and extrusion of the two canopies during inflation obstructed the oscillation of the inner gores.Concurrently,compared with the single-cruciform parachute,the vortex motion in the wake of double-cruciform-parachute is more intense.Thus the double-cruciform parachute system oscillated at a velocity of 50 m/s with an angle of less than 6.8°.By comparison,the oscillation angle of the single-cruciform parachute was within 3.5° at the velocity of 50m/s.The results are consistent with those of the wind tunnel test.展开更多
This paper is dedicated to applying the Fourier amplitude sensitivity test(FAST)method to the problem of mixed extension and inflation of a circular cylindrical tube in the presence of residual stresses.The metafuncti...This paper is dedicated to applying the Fourier amplitude sensitivity test(FAST)method to the problem of mixed extension and inflation of a circular cylindrical tube in the presence of residual stresses.The metafunctions and the Ishigami function are considered in the sensitivity analysis(SA).The effects of the input variables on the output variables are investigated,and the most important parameters of the system under the applied pressure and axial force such as the axial stretch and the azimuthal stretch are determined.展开更多
In recent years, inflatable structures have been a subject of interest for space applications such as communication antenna, solar thermal propulsion and entry/landing systems. The inflatable structures characterized ...In recent years, inflatable structures have been a subject of interest for space applications such as communication antenna, solar thermal propulsion and entry/landing systems. The inflatable structures characterized by high strength-to-mass ratios, minimal stowage volume, which makes them suitable for cost-effective large space structures. A typical example for the inflatable structure is the inflated torus which often used in order to provide structure support. In this study, our main focus is to understand the dynamic characteristics of an inflated torus in order to formulate an accurate mathematical model suitable for active vibration control applications. A commercial finite element package, ANSYS, is used to model the inflated torus. To verify the model the obtained frequencies and mode shapes are compared with the published results, which are derived using analytical approach, the verification shows a good agreement between the FEM and the analytical results. Based on the verified model, parametric study was investigated; the material thickness increase causes the natural frequencies decrease, while the increase of the inflation pressure simply results in stiffening the ring, which means that the natural frequency increased. The FEM analysis gives an easy and fast way for the vibration analysis of the structures compared with the complicated analytical solutions.展开更多
It is very important for gas-structure interaction between compressible ideal gas and elastic structure of space folded membrane booms during the inflatable deployment. In order to study this gas-structure interaction...It is very important for gas-structure interaction between compressible ideal gas and elastic structure of space folded membrane booms during the inflatable deployment. In order to study this gas-structure interaction problem, Arbitrary Lagrangian-Eulerian （ALE） finite element method was employed. Gas-structure interaction equation was built based on equilibrium integration relationship, and solved by operator split method. In addition, numerical analysis of V-shape folded membrane booms inflated by gas was given, the variation of inner pressure as well as deployment velocities of inflatable boom at different stage were simulated. Moreover, these results are consistent with the experiment of the same boom~ which shows that both ALE method and operator split method are feasible and reliable methods to study gas-structure interaction problem.展开更多
Hollow tubular tissues and organs of our body have various functions: gastrointestinal (esophagus), respiratory (trachea), and vascular (veins, arteries). A panel of pathologies is associated with each of these tissue...Hollow tubular tissues and organs of our body have various functions: gastrointestinal (esophagus), respiratory (trachea), and vascular (veins, arteries). A panel of pathologies is associated with each of these tissues and therapeutic interventions, surgery or replacement may be necessary. A precise knowledge of the mechanical properties of these tissues is thus required in order to understand their functioning in native conditions, to be able to elaborate some prostheses, or to design appropriate surgical training tools. These tissues may undergo expansions or contractions (peristalsis) and are exposed to internal pressures. The wall of tubular organs is organized in different layers, and each layer consists of various cell types and extra-cellular matrix, depending on the physiological functions that the organ has to fulfil. This yields anisotropic and compliant structures. In inflation experiments, the linear elasticity approach is acceptable as long as the organ’s inflation remains moderate. In this paper, elasticity laws are revisited and supplemented in order to show that, coupled with modern experimental characterization tools, they provide useful information (compliances, directional Young moduli, Poisson ratios) for the design of artificial tubular organs. The importance of a precise determination of the wall thickness and its evolution during inflation is pointed out.展开更多
We investigate the existence and the continuity of the inflated attractors for a class of non–autonomous strongly damped wave equations through differential inclusion.
Arabic Sign Language(ArSL)recognition plays a vital role in enhancing the communication for the Deaf and Hard of Hearing(DHH)community.Researchers have proposed multiple methods for automated recognition of ArSL;howev...Arabic Sign Language(ArSL)recognition plays a vital role in enhancing the communication for the Deaf and Hard of Hearing(DHH)community.Researchers have proposed multiple methods for automated recognition of ArSL;however,these methods face multiple challenges that include high gesture variability,occlusions,limited signer diversity,and the scarcity of large annotated datasets.Existing methods,often relying solely on either skeletal data or video-based features,struggle with generalization and robustness,especially in dynamic and real-world conditions.This paper proposes a novel multimodal ensemble classification framework that integrates geometric features derived from 3D skeletal joint distances and angles with temporal features extracted from RGB videos using the Inflated 3D ConvNet(I3D).By fusing these complementary modalities at the feature level and applying a majority-voting ensemble of XGBoost,Random Forest,and Support Vector Machine classifiers,the framework robustly captures both spatial configurations and motion dynamics of sign gestures.Feature selection using the Pearson Correlation Coefficient further enhances efficiency by reducing redundancy.Extensive experiments on the ArabSign dataset,which includes RGB videos and corresponding skeletal data,demonstrate that the proposed approach significantly outperforms state-of-the-art methods,achieving an average F1-score of 97%using a majority-voting ensemble of XGBoost,Random Forest,and SVM classifiers,and improving recognition accuracy by more than 7%over previous best methods.This work not only advances the technical stateof-the-art in ArSL recognition but also provides a scalable,real-time solution for practical deployment in educational,social,and assistive communication technologies.Even though this study is about Arabic Sign Language,the framework proposed here can be extended to different sign languages,creating possibilities for potentially worldwide applicability in sign language recognition tasks.展开更多
Continuously increasing inflation is a major challenge in presenting reliable and relevant financial reports,especially in developing countries like Indonesia.This study aims to analyze the role of inflation accountin...Continuously increasing inflation is a major challenge in presenting reliable and relevant financial reports,especially in developing countries like Indonesia.This study aims to analyze the role of inflation accounting in increasing the reliability of financial reports during times of high inflation.With a qualitative-descriptive approach,this research examines two main methods in inflation accounting,namely General Price Level Accounting(GPLA)and Current Cost Accounting(CCA),and their impact on the value of assets,liabilities,income,and costs.The analysis results show that historical cost-based financial reports do not reflect actual economic conditions during inflation,so they can be misleading in decision making.The application of inflation accounting,through adjustments to purchasing power and current prices,has been proven to be able to increase the relevance and reliability of financial information.However,limitations in implementation in Indonesia are due to the lack of regulations and practical understanding regarding this method.Therefore,the application of inflation accounting is important in supporting the quality of financial reports and more accurate decision making amidst economic instability.展开更多
In the Turkish Economy,there were radical changes in the structure of the economy with the policies of opening up to the outside world and transition to a free market economy in the 1980s,and the last step of this ope...In the Turkish Economy,there were radical changes in the structure of the economy with the policies of opening up to the outside world and transition to a free market economy in the 1980s,and the last step of this opening up and liberalization process was realized with the decision number 32 in 1989.We can say that with the liberalization of capital movements in the 1990s,economic growth and development were tried to be achieved through hot money inflows rather than direct foreign investments.This trend made the economy more open to crises,and for the first time,a crisis occurred in the form of the 1994 economic crisis,which was understood to be caused by hot money.The same economic structure experienced a financial and economic crisis caused by hot money again in November 2000 and February 2001.While the crisis was overcome with the stand-by agreement made with the IMF(International Monetary Fund)and the announced Transition to a Strong Economy program,the economy started to grow rapidly with the ease of using foreign resources,and political stability seems to have enabled this economic growth process to continue uninterruptedly except 2009.There was also a decrease in inflation rates.The same economic structure continued in the period between 2010 and 2020,and the financing need of economic growth was met by outsourcing.However,this process was different from the previous decade and there was no economic and financial crisis other than the sudden increase in exchange rates in 2018.We can say that the sudden exchange rate increase in 2018 was perceived as a harbinger of possible exchange rate shocks in the following years.展开更多
In the first half of 2025,the global textile machinery market continued to face significant headwinds,including economic slowdown,persistent inflation,and dampened consumer sentiment.According to Dr.Harald Weber,Manag...In the first half of 2025,the global textile machinery market continued to face significant headwinds,including economic slowdown,persistent inflation,and dampened consumer sentiment.According to Dr.Harald Weber,Managing Director of the VDMA Textile Machinery Association,German exports of textile machinery and accessories saw a yearon-year decrease of approximately 9%between January and May.This trend was not unique to Germany,as exports from all European countries also declined amid ongoing geopolitical tensions and unpredictable trade policies.Despite these challenges,the incoming orders are bottoming out,potentially signaling the beginning of an industry recovery.However,the protectionist policies have contributed to a cautious investment climate worldwide.And the protectionism is not limited to the U.S.,with subsidies and other unfair advantages for domestic companies distorting competition in multiple regions.Now,trade barriers are the most pressing challenge for the global textile industry,urging manufacturers to reduce strategic dependencies to mitigate risks.展开更多
The Philippine economy slowed in 2025 as domestic shocks,weaker investment,and soft global demand weighed on growth.However,a modest recovery is expected in 2026-2027,supported by resilient consumption and easing infl...The Philippine economy slowed in 2025 as domestic shocks,weaker investment,and soft global demand weighed on growth.However,a modest recovery is expected in 2026-2027,supported by resilient consumption and easing inflation,according to the World Bank's latest Phil-ippines Economic Update(PEU).展开更多
文摘In this paper,an experimental study of an air inflated membrane was carried out based on the China National Stadium (the Bird's Nest). After the 2008 Olympic Games,it was apparent that the future use of the Bird's Nest would be enhanced if rainfall could be prevented from entering the stadium. The installation of an air inflated membrane across the opening of the steel structure was proposed as a solution to this problem. To verify the scheme,a theoretical analysis and experimental study of an air inflated membrane was carried out. Experimental and computational models were developed,form-finding was carried out using both experimental and theoretical methods,and the results from the two approaches,including the deflection of the air inflated membrane and deformation of the support structure,were analyzed and compared. The force-transfer path and deformation of the air inflated membrane under loads was studied. Conclusions and suggestions are presented.
基金supported by the National Natural Science Foundation of China(No.12172102).
文摘This paper proposes a frequency reconfigurable triangular antenna actuated by an inflated triangular structure.The open path antenna is transformed from an open type to a closed structure by inflating.Inflatable structures are easy to manufacture by fusing 2 inextensible membranes together along a defined pattern of lines.However,the prediction of their deployed shape remains a challenge.To solve the pattern changed problem,guided by geometric analyses and local buckle characteristics,the inflated triangular structure has been designed and verified by experiment and simulation.In the process of transformation of the antenna,the resonant frequency of the antenna is changed because this frequency is determined by the conformational change.The resonant frequency changes from GHz to kHz when the design of initial structure sizes is from millimeter to meter.The measured peak gains,the frequency,and the radiation direction are also reconfigurable by the initial size.Finally,the reconfigurable resonator array is presented,which is coupled to electric fields to absorb all incident radiation.In this work,the changed pattern design by inflating is applied to the antenna design,and its frequency reconfigurability is achieved.Through the electricity performance analysis of the reconfigurable antenna,precise manufacturing will be possible and provide guidance for manufacturing frequency reconfigurable antennas.
基金Sponsored by the Program for New Century Excellent Talents in University (Grant No. NCET-08-0150)
文摘The bending stiffness of the inflated beam is considered as a constant before wrinkles appear, and it decreases obviously as wrinkles propagate. The formula of the bending stiffness is obtained based on the membrane theory in this paper. Furthermore, the definition of dimensionless bending stiffness factor is presented; the relationship of bending stiffness factor and wrinkling factor is derived; the bending stiffness factor is simplified as different linear functions with wrinkling factor, and the simplified model of bending stiffness of inflated beam under bending is also obtained. The bending stiffness including expression of wrinkling factor is substituted into the deflection differential equation, and then the slope and deflection equation of the inflated beam is deduced by integrating the deflection differential equation. Finally, the load-deflection curve is obtained, which is compared with the experimental data in a previous paper. It has a good agreement with each other.
文摘China National Stadium,also known as "Bird's Nest",is the main stadium of the 29th Olympic Games in Beijing in 2008,which has successfully held not only the Opening and the Closing ceremonies but also the track and field events.A new problem of rain preventing is brought out to improve the utilization of the Bird's Nest after the Olympic Games.The scheme of installing an air inflated membrane at the opening of the steel structure is proposed in this paper to solve the rainproof problem of the Bird's Nest.The form-finding and mechanical analyses of the air inflated membrane are carried out.Comparison between the mechanical performance and dynamical character before and after installing the air inflated membrane structure is given.To verify the analysis results,based on the practical structure of the Bird's Nest,a test of a 1:20 model membrane is worked out.
基金supported by the National Natural Science Foundation of China (10902027)Specialized Research Fund for the Doctoral Program of Higher Education of China (200802131046)+2 种基金China Postdoctoral Science Foundation (200801290)Development Program of Outstanding Young Teachers in Harbin Institute of Technology(HITQNJS.2008.004)Specialized Fund for Innovation Talents of Science and Technology in Harbin (2008RFQXG057)
文摘A new model is proposed to accurately predict the wrinkling and collapse loads of a membrane inflated beam. In this model, the pressure effects are considered and a modified factor is introduced to obtain an accurate prediction. The former is achieved by modifying the pressure-related structural parameters based on elastic small strain considerations, and the modified factor is determined by our test data. Compared with previous models and our test data, the present model, named as shell-membrane model, can accurately predict the wrinkling and collapse loads of membrane inflated beams.
基金the financial support from the National Natural Science Foundation of China(11872160)the Science Foundation of National Key Laboratory of Science and Technology on Advanced Composites in Special Environments,China(JCKYS2020603C007)。
文摘A floating air weapon system(such as airborne floating mines)plays an important role in modern air defense operations.This paper focuses on aeroelastic characteristics of airborne floating mine named inflated pillow.Firstly,the dynamic deployable process of the pillow and characteristics of the local instability of the edge are studied,and the evolution mechanism of wrinkles and kinks is analyzed.Secondly,in the cruising stage,the fluid-structural-thermal coupling analysis is performed on the pillow,and the aeroelastic characteristics are studied.Thirdly,the shapepreserving effect of the inflated pillow during the“negative pressure”slow landing stage is evaluated.It is found that when the wind velocity is higher,the pillow has a collapsed instability(surface extrusion and contact),and when the wind velocity is lower,snap-through instability occurs.Finally,for the collapsed instability,a carbon fiber skeleton is added to discrete the large global collapsed fold into small local folds,thus achieving shape-preserving effect of pillow.For snapthrough instability,the critical internal pressure and different shape evolution under different wind velocity are evaluated.Through the analysis of the mechanical mechanism and control of the structural morphological evolution,it provides theoretical guidance for the application of the curved shell structure in floating air weapon system.
文摘The present paper studies the contact problem of an inflated toroidal nonlinear anisotropic hyperelastic membrane laterally pressed between two flat rigid plates.The material is assumed to be homogeneous,and an anisotropic term is included in the incompressible Mooney–Rivlin hyperelastic model.Initially,two annular-shaped flat membranes,bonded at both equators,are considered in an undeformed state,which results in a toroidal geometry upon uniform internal pressurization.The contact problem of the inflated torus laterally pressed between two flat parallel plates is solved.Two different contact conditions,namely frictionless contact and no-slip contact,are considered within the contact region.The enclosed amount of gas within the inflated membrane is considered to be constant during the solution of the contact problem,which is solved in a quasi-static manner.In the case of no-slip contact,the stretch locking has been observed,and the frictionless contact causes the free flow of material points.The membrane’s stiffness increases with increasing anisotropic,material,and geometric parameters depicted in the force versus displacement curve under contact conditions.
基金supported in part by the Aeronautical Science Foundation of China(No.20172952031)the Aeronautical Science Foundation of China (No.20142952026)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The fluid-structure interaction (FSI) between the canopy and flow field on the inflating and inflated conditions is investigated based on the arbitrary Lagrange-Euler (ALE) method,in both a single-and double-cruciform parachute systems.The projection area of canopy is calculated in the inflation process.The flow field characteristics and the interaction between canopies are analyzed.Results showed that,with free stream velocity of 50m/s,overinflation phenomenon would not occur during the inflation process of the double-cruciform-parachute system,because the collision and extrusion of the two canopies during inflation obstructed the oscillation of the inner gores.Concurrently,compared with the single-cruciform parachute,the vortex motion in the wake of double-cruciform-parachute is more intense.Thus the double-cruciform parachute system oscillated at a velocity of 50 m/s with an angle of less than 6.8°.By comparison,the oscillation angle of the single-cruciform parachute was within 3.5° at the velocity of 50m/s.The results are consistent with those of the wind tunnel test.
文摘This paper is dedicated to applying the Fourier amplitude sensitivity test(FAST)method to the problem of mixed extension and inflation of a circular cylindrical tube in the presence of residual stresses.The metafunctions and the Ishigami function are considered in the sensitivity analysis(SA).The effects of the input variables on the output variables are investigated,and the most important parameters of the system under the applied pressure and axial force such as the axial stretch and the azimuthal stretch are determined.
文摘In recent years, inflatable structures have been a subject of interest for space applications such as communication antenna, solar thermal propulsion and entry/landing systems. The inflatable structures characterized by high strength-to-mass ratios, minimal stowage volume, which makes them suitable for cost-effective large space structures. A typical example for the inflatable structure is the inflated torus which often used in order to provide structure support. In this study, our main focus is to understand the dynamic characteristics of an inflated torus in order to formulate an accurate mathematical model suitable for active vibration control applications. A commercial finite element package, ANSYS, is used to model the inflated torus. To verify the model the obtained frequencies and mode shapes are compared with the published results, which are derived using analytical approach, the verification shows a good agreement between the FEM and the analytical results. Based on the verified model, parametric study was investigated; the material thickness increase causes the natural frequencies decrease, while the increase of the inflation pressure simply results in stiffening the ring, which means that the natural frequency increased. The FEM analysis gives an easy and fast way for the vibration analysis of the structures compared with the complicated analytical solutions.
基金supported by the National Natural Science Foundation of China (10902032)the National Key Laboratory Opening Funding of Advanced Composites in Special Environments (HIT.KLOF.2009035)
文摘It is very important for gas-structure interaction between compressible ideal gas and elastic structure of space folded membrane booms during the inflatable deployment. In order to study this gas-structure interaction problem, Arbitrary Lagrangian-Eulerian （ALE） finite element method was employed. Gas-structure interaction equation was built based on equilibrium integration relationship, and solved by operator split method. In addition, numerical analysis of V-shape folded membrane booms inflated by gas was given, the variation of inner pressure as well as deployment velocities of inflatable boom at different stage were simulated. Moreover, these results are consistent with the experiment of the same boom~ which shows that both ALE method and operator split method are feasible and reliable methods to study gas-structure interaction problem.
文摘Hollow tubular tissues and organs of our body have various functions: gastrointestinal (esophagus), respiratory (trachea), and vascular (veins, arteries). A panel of pathologies is associated with each of these tissues and therapeutic interventions, surgery or replacement may be necessary. A precise knowledge of the mechanical properties of these tissues is thus required in order to understand their functioning in native conditions, to be able to elaborate some prostheses, or to design appropriate surgical training tools. These tissues may undergo expansions or contractions (peristalsis) and are exposed to internal pressures. The wall of tubular organs is organized in different layers, and each layer consists of various cell types and extra-cellular matrix, depending on the physiological functions that the organ has to fulfil. This yields anisotropic and compliant structures. In inflation experiments, the linear elasticity approach is acceptable as long as the organ’s inflation remains moderate. In this paper, elasticity laws are revisited and supplemented in order to show that, coupled with modern experimental characterization tools, they provide useful information (compliances, directional Young moduli, Poisson ratios) for the design of artificial tubular organs. The importance of a precise determination of the wall thickness and its evolution during inflation is pointed out.
文摘We investigate the existence and the continuity of the inflated attractors for a class of non–autonomous strongly damped wave equations through differential inclusion.
基金funding this work through Research Group No.KS-2024-376.
文摘Arabic Sign Language(ArSL)recognition plays a vital role in enhancing the communication for the Deaf and Hard of Hearing(DHH)community.Researchers have proposed multiple methods for automated recognition of ArSL;however,these methods face multiple challenges that include high gesture variability,occlusions,limited signer diversity,and the scarcity of large annotated datasets.Existing methods,often relying solely on either skeletal data or video-based features,struggle with generalization and robustness,especially in dynamic and real-world conditions.This paper proposes a novel multimodal ensemble classification framework that integrates geometric features derived from 3D skeletal joint distances and angles with temporal features extracted from RGB videos using the Inflated 3D ConvNet(I3D).By fusing these complementary modalities at the feature level and applying a majority-voting ensemble of XGBoost,Random Forest,and Support Vector Machine classifiers,the framework robustly captures both spatial configurations and motion dynamics of sign gestures.Feature selection using the Pearson Correlation Coefficient further enhances efficiency by reducing redundancy.Extensive experiments on the ArabSign dataset,which includes RGB videos and corresponding skeletal data,demonstrate that the proposed approach significantly outperforms state-of-the-art methods,achieving an average F1-score of 97%using a majority-voting ensemble of XGBoost,Random Forest,and SVM classifiers,and improving recognition accuracy by more than 7%over previous best methods.This work not only advances the technical stateof-the-art in ArSL recognition but also provides a scalable,real-time solution for practical deployment in educational,social,and assistive communication technologies.Even though this study is about Arabic Sign Language,the framework proposed here can be extended to different sign languages,creating possibilities for potentially worldwide applicability in sign language recognition tasks.
文摘Continuously increasing inflation is a major challenge in presenting reliable and relevant financial reports,especially in developing countries like Indonesia.This study aims to analyze the role of inflation accounting in increasing the reliability of financial reports during times of high inflation.With a qualitative-descriptive approach,this research examines two main methods in inflation accounting,namely General Price Level Accounting(GPLA)and Current Cost Accounting(CCA),and their impact on the value of assets,liabilities,income,and costs.The analysis results show that historical cost-based financial reports do not reflect actual economic conditions during inflation,so they can be misleading in decision making.The application of inflation accounting,through adjustments to purchasing power and current prices,has been proven to be able to increase the relevance and reliability of financial information.However,limitations in implementation in Indonesia are due to the lack of regulations and practical understanding regarding this method.Therefore,the application of inflation accounting is important in supporting the quality of financial reports and more accurate decision making amidst economic instability.
文摘In the Turkish Economy,there were radical changes in the structure of the economy with the policies of opening up to the outside world and transition to a free market economy in the 1980s,and the last step of this opening up and liberalization process was realized with the decision number 32 in 1989.We can say that with the liberalization of capital movements in the 1990s,economic growth and development were tried to be achieved through hot money inflows rather than direct foreign investments.This trend made the economy more open to crises,and for the first time,a crisis occurred in the form of the 1994 economic crisis,which was understood to be caused by hot money.The same economic structure experienced a financial and economic crisis caused by hot money again in November 2000 and February 2001.While the crisis was overcome with the stand-by agreement made with the IMF(International Monetary Fund)and the announced Transition to a Strong Economy program,the economy started to grow rapidly with the ease of using foreign resources,and political stability seems to have enabled this economic growth process to continue uninterruptedly except 2009.There was also a decrease in inflation rates.The same economic structure continued in the period between 2010 and 2020,and the financing need of economic growth was met by outsourcing.However,this process was different from the previous decade and there was no economic and financial crisis other than the sudden increase in exchange rates in 2018.We can say that the sudden exchange rate increase in 2018 was perceived as a harbinger of possible exchange rate shocks in the following years.
文摘In the first half of 2025,the global textile machinery market continued to face significant headwinds,including economic slowdown,persistent inflation,and dampened consumer sentiment.According to Dr.Harald Weber,Managing Director of the VDMA Textile Machinery Association,German exports of textile machinery and accessories saw a yearon-year decrease of approximately 9%between January and May.This trend was not unique to Germany,as exports from all European countries also declined amid ongoing geopolitical tensions and unpredictable trade policies.Despite these challenges,the incoming orders are bottoming out,potentially signaling the beginning of an industry recovery.However,the protectionist policies have contributed to a cautious investment climate worldwide.And the protectionism is not limited to the U.S.,with subsidies and other unfair advantages for domestic companies distorting competition in multiple regions.Now,trade barriers are the most pressing challenge for the global textile industry,urging manufacturers to reduce strategic dependencies to mitigate risks.
文摘The Philippine economy slowed in 2025 as domestic shocks,weaker investment,and soft global demand weighed on growth.However,a modest recovery is expected in 2026-2027,supported by resilient consumption and easing inflation,according to the World Bank's latest Phil-ippines Economic Update(PEU).
