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INCLINED LAMINAL COMBINATION MODEL OF 3D BRAIDED COMPOSITES
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作者 周光明 王鑫伟 乔新 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1995年第1期8-14,共7页
As an advanced composite material, the 3D braided composite has received more and more attention in foreign countries. However, it has received less attention in China. The geometric unit cell which can describe the b... As an advanced composite material, the 3D braided composite has received more and more attention in foreign countries. However, it has received less attention in China. The geometric unit cell which can describe the basic structure and the relationship between the braiding angle and geometric parameters of the fabric and fiber volume ratio are given in this paper based on two 3D braiding processes, namely, the four-step and the twostep ones. Several existing mechanical models to predict groperties of the 3D braided comPOsites are discussed and their shortcomings are pointed out herein. Then a new model called the inclined laminal combination model is proposed, which is based on the classical laminated plate theory and can predict the basic mechanical behavior of the two 3D braided composites with four-step or two-step braid. In the model, each yarn in the unit cell is regarded as an inclined laminate and then a 3D analysis is performed. It is found that the predicted mechanical properties of the 3D braided composites by the proposed model are compared well with the experimental data. 展开更多
关键词 COMPOSITES mechanical properties unit cell mechanical model 3d braided
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Yarn Architecture Analysis of Two-step 3D Braided Composites
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作者 孙颖 亢一澜 李嘉禄 《Journal of Donghua University(English Edition)》 EI CAS 2005年第3期126-132,共7页
A comprehensive study of yarn architecture of two-step rectangle 3D braided composites is presented. Firstly, the braided surface, the shapes of yarns and the intertwining between braider yams and axial yams are analy... A comprehensive study of yarn architecture of two-step rectangle 3D braided composites is presented. Firstly, the braided surface, the shapes of yarns and the intertwining between braider yams and axial yams are analyzed from experimentation. With the microstructure being defined, three levels of unit cell structure are identified, i.e. large unit cell, second unit cell and minimal unit cell. Secondly, based on the minimal unit cell in the interior and on the boundary of the entire cross-section, the deformations of axial yams squashed by braider yams contribute to the increase of the fiber packing factors of axial yams. Finally, the predicted fiber volume fraction of the composites decreases with the increase of linear density of the braider yam and the pitch length. Favorable correlations between the predicted and the experimental results arc found for six groups of the composites. 展开更多
关键词 composites mo -step 3d braided yarn geometry fiber volume fraction DEFORMATION
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Electrical⁃Mechanical Coupling Behaviors and Thermal⁃Resistance Effects of 3D Braided Composites
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作者 BAI Lei XUE Yousong +2 位作者 SUN Baozhong GU Bohong HU Meiqi 《Journal of Donghua University(English Edition)》 CAS 2021年第5期385-391,共7页
Electrical-mechanical coupling behaviors and thermal-resistance effects of 3D braided composites under external loads are important for structural health monitoring(SHM). Electrical conductivity and electrical-mechani... Electrical-mechanical coupling behaviors and thermal-resistance effects of 3D braided composites under external loads are important for structural health monitoring(SHM). Electrical conductivity and electrical-mechanical coupling behaviors of 3D braided carbon fiber/epoxy composites under uniaxial tension were reported. It was found that the transverse resistance decreased and the axial resistance increased with the increasing braiding angle. The fractional change in resistance increased linearly as the strain was below 1.0%, and the nonlinearity appeared when the strain exceeded 1.0%. The negative temperature coefficient(NTC) effect was observed before the glass transition temperature Tg of epoxy resin, while there was a positive temperature coefficient(PTC) effect after Tg. 展开更多
关键词 3d braided composite braided angle electrical property thermal analysis
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Defects Recognition of 3D Braided Composite Based on Dual-Tree Complex Wavelet Packet Transform
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作者 贺晓丽 王瑞 《Journal of Donghua University(English Edition)》 EI CAS 2015年第5期749-752,共4页
Textile-reinforced composites,due to their excellent highstrength-to-low-mass ratio, provide promising alternatives to conventional structural materials in many high-tech sectors. 3D braided composites are a kind of a... Textile-reinforced composites,due to their excellent highstrength-to-low-mass ratio, provide promising alternatives to conventional structural materials in many high-tech sectors. 3D braided composites are a kind of advanced composites reinforced with 3D braided fabrics; the complex nature of 3D braided composites makes the evaluation of the quality of the product very difficult. In this investigation,a defect recognition platform for 3D braided composites evaluation was constructed based on dual-tree complex wavelet packet transform( DT-CWPT) and backpropagation( BP) neural networks. The defects in 3D braided composite materials were probed and detected by an ultrasonic sensing system. DT-CWPT method was used to analyze the ultrasonic scanning pulse signals,and the feature vectors of these signals were extracted into the BP neural networks as samples. The type of defects was identified and recognized with the characteristic ultrasonic wave spectra. The position of defects for the test samples can be determined at the same time. This method would have great potential to evaluate the quality of 3D braided composites. 展开更多
关键词 3d braided composite dual-tree complex wavelet packet transform(DT-CWPT) ultrasonic wave
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Effects of Microstructure on Quasi⁃Static Transverse Loading Behavior of 3D Circular Braided Composite Tubes
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作者 ZHOU Haili LI Chao +3 位作者 HAN Chenchen LIU Zhiyan ZHOU Feng ZHANG Liquan 《Journal of Donghua University(English Edition)》 CAS 2021年第5期392-397,共6页
The effects of microstructure on quasi-static transverse loading behavior of 3D circular braided composite tubes were studied. Transverse loading tests were conducted. Transverse load-deflection curves were obtained t... The effects of microstructure on quasi-static transverse loading behavior of 3D circular braided composite tubes were studied. Transverse loading tests were conducted. Transverse load-deflection curves were obtained to analyze the effects of braiding parameters including the braiding angle, the wall thickness, and the diameter on the transverse loading of 3D circular braided composite tubes. Breaking loads, moduli and strengths had also been used to describe the transverse loading behaviors. The failure morphologies were shown to reveal damage mechanisms. From the results, the increase in braiding angle, wall thickness and diameter increases the ability of anti-deformation and breaking load of braided tubes. The breaking load of specimen with a braiding angle of 45° is about 1.68 times that of specimen with a braiding angle of 15°. The breaking load of specimen with 4 layers of yarns is about 2.15 times that of specimen with 2 layers of yarns. The breaking load of the tube with a diameter of 25.5 mm is about 2.39 times that of the tube with a diameter of 20.5 mm. 展开更多
关键词 3d circular braided composite tube quasi⁃static transverse loading test braiding parameter failure morphology
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Theoretical prediction of stiffness and strength of three-dimensional and four-directional braided composites
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作者 李典森 卢子兴 卢文书 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第2期163-170,共8页
Based on unit cell model, the 3D 4-directional braided composites can be simplified as unidirectional composites with different local axial coordinate system and the compliance matrix of unidirectional composites can ... Based on unit cell model, the 3D 4-directional braided composites can be simplified as unidirectional composites with different local axial coordinate system and the compliance matrix of unidirectional composites can be defined utilizing the bridge model. The total stiffness matrix of braided composites can be obtained by the volume average stiffness of unidirectional composites with different local axial coordinate system and the engineering elastic constants of braided composites were computed further. Based on the iso-strain assumption and the bridge model, the stress distribution of fiber bundle and matrix of different unidirectional composites can be determined and the tensile strength of 3D 4-directional braided composites was predicted by means of the Hoffman's failure criterion for the fiber bundle and Mises' failure criterion for the matrix. 展开更多
关键词 3d braiding STRENGTH STIFFNESS mechanical properties composites
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Tensile Properties of 3-Dimension-4-directional Braided C_f/Si C Composite based on Double-scale Model 被引量:1
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作者 牛序铭 SUN Zhigang +1 位作者 宋迎东 GAO Xiguang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第6期1271-1279,共9页
The longitude tensile properties of 3-Dimension-4-directional(3D-4d) braided C/Si C composites(CMCs) were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In... The longitude tensile properties of 3-Dimension-4-directional(3D-4d) braided C/Si C composites(CMCs) were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In micro-scale, the tensile properties of fiber tows which involves matrix cracking, interfacial debonding, and fiber failure are studied. The unit-cell scale model can reflect the braided structure and simulate the tensile properties of 3D-4d CMCs by introducing the tensile properties of fiber tows into it. Quasi-static tensile tests of 3D-4d braided CMCs were performed on a PWS-100 test system. The predicted tensile stressstrain curve by the double scale model is in good agreement with that of the experimental results. 展开更多
关键词 3d-4d braided C/SiC composites double-scale model stress-strain curve fiber tows
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Elastic Modulus Prediction of Three-dimension-4 Directional Braided C_f/SiC Composite Based on Double-scale Model
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作者 牛序铭 SUN Zhigang +1 位作者 KONG Chunyuan 宋迎东 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第3期500-508,共9页
Double-scale model for three-dimension-4 directional(3D-4d) braided C/SiC composites has been proposed to investigate its elastic properties. The double-scale model involves micro-scale that takes fiber/ matrix/poro... Double-scale model for three-dimension-4 directional(3D-4d) braided C/SiC composites has been proposed to investigate its elastic properties. The double-scale model involves micro-scale that takes fiber/ matrix/porosity in fibers tows into consideration with unit cell which considers the 3D-4d braiding structure. Micro-optical photographs of composites have been taken to study the braided structure. Then a parameterized finite element model that reflects the structure of 3D-4d braided composites is proposed. Double-scale elastic modulus prediction model is developed to predict the elastic properties of 3D-4d braided C/SiC composites. Stiffness and eompliance-averaging method and energy method are adopted to predict the elastic properties of composites. Static-tension experiments have been conducted to investigate the elastic modulus of 3D-4d braided C/SiC composites. Finally, the effect of micro-porosity in fibers tows on the elastic modulus of 3D-4d braided C/SiC composites has been studied. According to the conclusion of this thesis, elastic modulus predicted by energy method and stiffness-averaging method both find good agreement with the experimental values, when taking the micro-porosity in fibers tows into consideration. Differences between the theoretical and experimental values become smaller. 展开更多
关键词 3d-4d braided C/SiC composites double-scale model elastic modulus energy methodstiffness and compliance-averaging method porosity ratio
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Using Acoustic Emissions to Detect Damage in Three-Dimensional Braided Composites
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作者 李怡 万振凯 李嘉禄 《Journal of Donghua University(English Edition)》 EI CAS 2010年第4期589-592,共4页
Three-dimensional(3D)braided composites with better properties have been used in some particular industries.Some have had obvious signs of crack when they are braided.Others have had catastrophic failures occuring wit... Three-dimensional(3D)braided composites with better properties have been used in some particular industries.Some have had obvious signs of crack when they are braided.Others have had catastrophic failures occuring without warning.A new methodology for the analysis of failure modes in composite materials by means of acoustic emission techniques has been developed.The occurrence of fiber-breakage during tensile loading tests has been observed by the acoustic emission technology.Using acoustic emission technology is investigated as a means of monitoring 3D braided composites structures,detecting damage,and predicting impending damage.Some of the findings of the research project were presented. 展开更多
关键词 three-dimensional(3d)braided composites acoustic emission fiber fragmentation
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A New Scheme and Microstructural Model for 3D Full 5-directional Braided Composites 被引量:14
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作者 Zhang Fan,Liu Zhenguo,Wu Zhe,Tao Guoquan School of Aeronautic Science and Engineering,Beijing University of Aeronautics and Astronautics,Beijing 100191,China 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2010年第1期61-67,共7页
Three-dimensional(3 D)braided composites are a kind of advanced ones and are used in the aeronautical and astronautical fields more widely. The advantages, usages, shortages and disadvantages of 3D braided composite... Three-dimensional(3 D)braided composites are a kind of advanced ones and are used in the aeronautical and astronautical fields more widely. The advantages, usages, shortages and disadvantages of 3D braided composites are analyzed, and the possible approach of improving the properties of the materials is presented, that is, a new type of 3D full 5-directional braided composites is developed. The methods of making this type of preform are proposed. It is pointed out that the four-step braiding which is the most possible to realize industrialized production almost has no effect on the composites' properties. By analyzing the simulation model,the advantages of the material compared with the 3D 4-directional and 5-directional materials are presented. Finally, a microstructural model is analyzed to lay the foundation for the future theoretical analysis of these composites. 展开更多
关键词 3d braided fabrics four-step braiding 3d full 5-directional braided composites preform microstructure
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Nonlinear bending analysis of a 3D braided composite cylindrical panel subjected to transverse loads in thermal environments 被引量:5
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作者 Yi-Xi ZHAO Tao LIU Zhi-Min LI 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2018年第8期1716-1727,共12页
The aim of this study is to investigate nonlinear bending for a 3-Dimensional(3D)braided composite cylindrical panel which has transverse loads on its finite length. By refining a micro-macro-mechanical model, the 3... The aim of this study is to investigate nonlinear bending for a 3-Dimensional(3D)braided composite cylindrical panel which has transverse loads on its finite length. By refining a micro-macro-mechanical model, the 3D braided composite can be treated as a representative average cell system. The geometric structural properties of its components deeply depend on their positions in the section of the cylindrical panel. The embedded elastic medium of the panel can be described by a Pasternak elastic foundation. Via using the shell theory of the von Ka′rma′nDonnell type of kinematic nonlinearity, governing equations can be established to get higherorder shear deformation. The mixed Galerkin-perturbation method is applied to get the nonlinear bending behavior of the 3D braided cylindrical panel with a simply supported boundary condition.Based on the analysis of the braided composite cylindrical panel with variable initial stress, geometric parameter, fiber volume fraction, and elastic foundation, serial numerical illustrations are archived to represent the appropriate nonlinear bending responses. 展开更多
关键词 3d braided Analytical modeling BENDING PANEL Thermal environments
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Numerical simulation on thermal expansion coefficient of 3D braided C/C composites 被引量:6
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作者 Chun-Xia Hu He-Jun Li +1 位作者 Shou-Yang Zhang Yong-Shan Song 《Rare Metals》 SCIE EI CAS CSCD 2014年第1期99-106,共8页
To effectively get the thermal expansion coef- ficient (CTE) of three-dimensional (3D) braided C/C composites and study the variations, a VC++ program with graphical user interfaces was obtained, based on the ya... To effectively get the thermal expansion coef- ficient (CTE) of three-dimensional (3D) braided C/C composites and study the variations, a VC++ program with graphical user interfaces was obtained, based on the yam unit model and numerical analysis. With the limited basic properties of carbon fibers and carbon matrix, CTE of 3D braided C/C composites is obtained at 85 ~C. The deviation between the simulated and exl^erimental axial CTE of 3D braided C/C composites is no more than 11%. The effects of different parameters (including the braiding angle of 3D braided preform, the fiber volume fraction and the porosity of 3D braided C/C composites, and the elastic modulus, Poisson's ratio and CTEs of carbon fibers and carbon matrix) were analyzed with the program. The results show that the axial CTE of C/C composites decreases with the increase of the braiding angle, the fiber volume fraction, and the porosity of 3D braided C/C composites. The transverse elastic modulus of carbon fibers has the greatest effect on the axial CTE among the studied mechanical parameters, followed by the elastic modulus and Poisson's ratio of carbon matrix. 展开更多
关键词 3d braided C/C composites Rosen-Hashin equation Axial CTE Simulation
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Damage Simulation for 3D Braided Composites by Homogenization Method 被引量:3
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作者 Dong Jiwei Feng Miaolin 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2010年第6期677-685,共9页
In order to study the failure patterns and strength of 3D braided composites from the microscopic view, the damage propagation under tensile loading steps in three kinds of unit cells is simulated. The homogenization ... In order to study the failure patterns and strength of 3D braided composites from the microscopic view, the damage propagation under tensile loading steps in three kinds of unit cells is simulated. The homogenization formula of micro-stress and the solving approach of finite element method are given firstly. A criterion is presented to determine the damage and its pattern of each element, and then the stiffness degradation method based on Murakami's geometric damage theory is used to simulate the status of damage under tensile loading steps for three kinds of unit cells. It can be seen that the damage percentage and damage pattern of damaged unit cell are totally different for different kind of unit cells. More damaged elements are observed for face cell and corner cell than that for body cell. It is also observed that the damage firstly occurs at the area of face cell, which agrees well with experimental results. It is verified that considering the effects of face and corner cells are important for the damage and strength analysis of 3D braided composites. 展开更多
关键词 DAMAGE 3d braided composites meso-structure HOMOGENIZATION finite element method
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Postbuckling behavior of 3D braided rectangular plates subjected to uniaxial compression and transverse loads in thermal environments 被引量:3
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作者 CHU GuoPing LI ZhiMin 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第7期1439-1453,共15页
Postbuckling behavior of the 3D braided rectangular plates subjected to uniaxial compression combined with transverse loads in thermal environments is presented.Based on a micro-macro-mechanical model,a 3D braided com... Postbuckling behavior of the 3D braided rectangular plates subjected to uniaxial compression combined with transverse loads in thermal environments is presented.Based on a micro-macro-mechanical model,a 3D braided composite may be treated as a cell system and the geometry of each cell is deeply dependent on its position in the cross-section of the plate.The material properties of the epoxy are expressed as a linear function of temperature.Uniform,linear and nonlinear temperature distributions through the thickness are involved.The lateral pressure(three types of transverse loads,i.e.transverse uniform load;transverse patch load over a central area;and transverse sinusoidal load)is first converted into an initial deflection and the initial geometric imperfection of the plate is taken into account.The governing equations are based on Reddy’s higher-order shear deformation plate theory with a von Kármán-type of kinematic nonlinearity.Two cases of the in-plane boundary conditions are also taken into account.A perturbation technique is employed to determine buckling loads and postbuckling equilibrium paths of simply supported 3D braided rectangular plates.The results reveal that the temperature rise,geometric parameter,fiber volume fraction,braiding angle,the character of the in-plane boundary conditions and different types of initial transverse loads have a significant effect on the buckling and postbuckling behavior of the braided composite plates. 展开更多
关键词 3d braided composite plate higher-order shear deformation plate theory BUCKLING POSTBUCKLING transverse loads thermal environment
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