Table of Content

28 September 2013, Volume 0 Issue 6

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ASSESSMENT FOR PLACEMENT SUITABILITY OF PREPREG-PART of TACK

HUANG Wen-zong, SUN Rong-lei, LIAN Hai-tao, WANG Qing-you

2013, 0(6):  3-11. 

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In the process of automated tape laying (ATL), tack and drape are two characteristics that describe the suitability of prepreg for lay-up. Tack and drape researched individually can help us understand placement suit-ability of prepreg better. This paper aims at tack of prepreg. Firstly, physical meaning of prepreg's tack was dis-cussed. Secondly, The existing measurement and characterization methods of prepreg's tack were summarized and using“average peeling force”quantitatively characterizing the tack of prepreg was proposed. Finally, influences of the main processing parameters of ATL, such as out time, lay-up pressure, lay-up velocity, hot-air temperature etc.on prepreg's tack were researched on the test platform which was constructed by ourselves. The experimental results indicate that the tack increases first and then decreases with out time, while increases with higher pressure of lay-up, higher temperature of hot-air and lower velocity of lay-up in the range of concentrations. The research provides a reference for the control of the processing parameters of ATL.

COMPARISON OF VARTM AND RTM PROCESS BY SIMULATION

WANG Qing-tao, ZHU Jia-qiang, LI Wei

2013, 0(6):  12-15. 

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This paper tested viscosity of the unsaturated polyester resin (UPR) adding aluminum hydroxide (ATH) in different temperatures and the content of accelerator by digital viscosity instrument, and simulated VARTM(resin transfer molding) and RTM(vacuum assisted resin transfer molding) process using a composite part. The simulation results show that: the filling time of VARTM process is not longer than RTM process, and when the inlet is larger than the outlet, the filling time of VARTM process is almost equal to RTM process, when the inlet is smaller than the outlet, the filling time of VARTM Process is less than RTM's.

STUDY ON THE LIQUID COMPOSITE MOLDING AND THE PROPERTIES OF CARBON FIBER REINFORCED EPOXY RESIN COMPOSITES

MU Shu-xiang, JIA Zhi-yuan

2013, 0(6):  16-20. 

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The viscosity and pot life of RIM145 resin at different temperatures were studied and the wettability between carbon fiber and RIM145 resin under varied temperatures were also analyzed. Using RIM145 rein as the matrix and UD carbon fabric as the reinforcement, carbon fiber reinforced epoxy resin (CF/EP) composites were prepared by the vacuum assisted resin transfer molding (VARTM) process. The mechanical properties of the CF/EP composites were investigated and SEM morphology of the fracture and slip surface of the sample used for interlaminar shear strength testing were observed. The research results showed that the RIM145 resin matrix had a series of characteristic performance such as low-viscosity, a long-working life and good-wettablity with carbon fiber filament at 50 ~ 70℃, was suitable for VARTM process. The prepared CF/EP composites had excellent mechanical performance and middle-level bonding performance interface.The porosity of the CF/EP composites can be lowered by assisting the VARTM process using VAP membrane.

INFLUENCE OF TWIST NUMBER ON SATURATION AND MECHANICAL PROPERTIES OF CHAIN-STITCH COMPOSITES

CHEN Ji-ping, SU Jia-zhi, ZHENG Yi-zhu

2013, 0(6):  21-26. 

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The Kevlar-29 fiber yarns of different twist numbers are used to stitch carbon fiber laminate performs respectively with chain-stitch style, and then process them with VARI (vacuum assisted resin infusion). The tensile strength, flexural strength and interlaminal shearing strength of the composite laminates with different twist numbers are studied. The saturation of Kevlar yarns with different twist numbers in the resin matrix was also presented in this paper. The results show that the tensile and flexural strength of the stitched laminate will enhance in varying degrees with increase of twist number which the interlaminal shearing strength reduced. According to the test data, tensile and flexural strength of the stitched laminate (80m–1 ) enhance 2. 5% and 9% comparing with stitched laminate(20m–1 ), and the interlaminal shearing strength reduces 12%. Meanwhile, the resin can saturate the Kevlar yarns well when twist number is low which the result will be opposite with high twist number.

ANALYSIS ON REFINED FINITE ELEMENT METHOD OF GLASS FIBER REINFORCED POLYMER CHIMNEY

WANG Ying-jun, ZHAO Ying, HE Fu-tian, CHEN Jian-zhong

2013, 0(6):  27-30. 

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Since there are not many specifications applied to design fiber-reinforced-plastic (FRP) chimney in China, so specifications on steel chimney, reinforced concrete chimney and masonry chimney are employed to design FRP chimney. However, this method has many limitations: for FRP chimney is simplified as the isotropic cantilever model which has neglected characters of composites, so it's hard to make local structural analysis. In this article, a sophisticated finite element model of FRP chimney is built, then the structural responses under multiloading cases according to current codes are performed. Stress and strain condition of the local area of FRP chimney are obtained, and strength analyses are proceeded according to laminated anisotropic composite shell theory and Tsai-Wu failure criteria. This way can realize more exact design than the conventional method.

FINITE ELEMENT ANALYSIS OF PLUG-IN COMPOSITE SINGLE POLE

ZHU Ke, HE Chang-lin, MA Xiao-min

2013, 0(6):  31-35. 

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Taking the single tower of a flange type made of composite material as study background, composite single pole of a plug-in type was designed in the same design conditions as the original project, and under three typical load conditions, its stresses, deflections and stability safety factors were simulated and analyzed by FEM(finite element method) software. Results reveal that the hoop stress in the plug-in area is too large and in the weak location of the structure. Two reinforcement programs in the plug-in area were put forward and calculated and results show: for internal intubation, the effect of using steel liners as reinforcement is relatively obvious. Finally, the single pole of plug-in type was designed for anti-torsion, and a methods of using glue and bolts to prevent the pole from torsion was put forward.

RING STIFFNESS ANALYSIS OF GLASS FIBER REINFORCED PLASTICS MORTAR PIPE

YANG Jian-ming, CHEN Jian-zhong

2013, 0(6):  36-39. 

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The concepts of ring stiffness, pipe stiffness and nominal stiffness of the glass fiber reinforced plastics mortar pipe are analyzed. Ring stiffness is a kind of ability of pipe ring under the action of the external load resistance to deformation. Pipe stiffness and ring stiffness is not the same concept, and nominal stiffness is the initial specific ring stiffness level. The basic method of design and test of ring stiffness is analyzed, and according to the design requirements of nominal stiffness required in practical engineering are analyzed from two aspects of deflection and buckling. The basic principles and methods of determine nominal stiffness and the relationship between ring stiffness and embedment conditions are obtained. It has reference significance to correctly understand ring stiffness of glass fiber reinforced plastics mortar pipe and ring stiffness design, test and selection.

MEASURES AND TEST OF LIGHTNING PROTECTION OF AIRPLANE COMPOSITE MATERIALS

ZHAO Jin-long, CHEN Xiao-ning, GENG Yong, ZHANG Bin

2013, 0(6):  40-43. 

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With the use of composite materials on aircraft, the lightning protection problems gradually get people's attention. This paper briefly describes several lightning protection measures currently widely used. From view of physical tests, the paper uses simulated lightning test to verify the effect of lightning protection for composite plates with protective measures. The test involves two different samples: regular composite plates and composite plates covering the protective layer of copper mesh. Through comparing the different results after two samples being struck by lightning, the paper finds that the protective layer of copper mesh is effective and important.

EVALUATION OF A HIGH TEMPERATURE-RESISTANT BISPHENOL A TYPE 2H-CHROMENE RESINS AS THE MATRIX OF COMPOSITES

CHENG Kai, YANG Guang, GAO Long-fei

2013, 0(6):  44-47. 

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Bisphenol A type 2H-bichromene resins (BCA resins) were successfully prepared by heating bipropargyl ether bisphenol A (BPA) in infrared-ray oven at 185℃ for 3h. The curing behaviors of BCA resins were studied by differential scanning calorimetry (DSC). It showed the cured enthalpy was decreased to 620J/g for BCA resin. Thermal stability of the cured BCA resin was also investigated by thermal gravimetric analysis (TGA). The results of TGA revealed that the cured BCA resin possessed excellent thermal stability. Based on the BCA resins, the glass fiber reinforced composites were prepared via press molding process. In comparison of Epoxy matrix composites, the composites of BCA resins presented higher mechanical properties. The flexural strength, flexural modulus and shear strength reached to 580MPa, 24. 7GPa and 40MPa respectively. In additional, the result of dynamic mechanical thermal analysis (DMTA) indicated composite had excellent thermal stability.

THE DISCUSSION OF DESIGNING FIBER REINFORCE PLASTIC TRANSMISSION TOWER

LIU Huan-huan, LIU Ming-hui, YU Xin

2013, 0(6):  48-52. 

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The paper introduced a method to design FRP transmission tower, used an optimization algorithm calculating the most suitable structure for FRP transmission tower, and build a mathematical model in ANSYS for 110kV FRP transmission tower. The experiment illustrated that the mathematical model in this paper is credible.

SYNTHESIS AND CHARACTERIZATION OF POLYANILINE-PALLADIUM NANOCOMPOSITES VIA IN-SITU REDUCTION METHOD

FAN Jing-xiong, YANG Ji-ping

2013, 0(6):  53-56. 

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In this paper, polyaniline-palladium nanocomposites, a kind of fuel cell catalysts in the system of formic acid, were successfully prepared by the method of in-situ reduction, in which palladium nitrate was used as the precursor of palladium nanoparticles and polyaniline (PANI) as the reductant and supporter of resulting palladium nanoparticles. The difference between doping PANI and dedoping PANI was studied and the final products were characterized using FT-IR, UV-Vis, X-ray diffraction (XRD), SEM and cyclic voltammetry(CV). The CV results suggested that the composites had the capability of catalyzing formic acid, while the dedoping one showed better performance than the doping one.

THE RESEARCH PROCESS OF SMART MATERIALS

ZHANG Xin-min

2013, 0(6):  57-63. 

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As a kind of new multifunctional materials, smart materials have drawn many attentions, plentiful and substantial research results in this field are also obtained. This paper summarized the research process of smart materials and presented the piezoelectric materials, shape memory materials, electrostriction materials, magnetostriction materials, electroreoloical fuids materials and magnetorheologieal fluids materials based on their operating principle, materials classification and application. Finally, the researching development tendency of the smart materials was prospect.

DISCUSSION ON THE APPLICATION OF FMEA IN THE DESIGN AND DEVELOPMENT OF COMPOSITE MATERIALS

DU Zhi-hua, XIONG Hong-mei, YANG De-xu, CUI Qiao-li

2013, 0(6):  64-66. 

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In the early stages of product formation, it was important to identify potential failure causes and take preventive measures for the development of composite products, especially for engine parts and other high-tech products. This paper introduced the application of FMEA technology in the composite engine component design and development. Through the analysis of potential causes of failure, it found that the design of oil pan external ribs was the main factors affecting the product whether withstand the flying rocks impact to avoid product leakage. Through the stone impact test, it verified the reliability of the external structure design and effectively reduced the risk of product development.