COMPOSITES SCIENCE AND ENGINEERING

FLEXURAL EXPERIMENTAL STUDY ON CONTINUOUS BEAMS STRENGTHENED WITH BFRP

OUYANG Li-jun, LU Zhou-dao, DING Bin

2013, 0(2): 3-7.

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Continuous basalt fibre reinforced polymer/plastic(BFRP) is a new fibrous composite. Compared with other fiber reinforced polymer/plastic,BFRP has many advantages in ductility,high thermal resistance,corrosion resistance and cost. Flexural experimental are conducted on four two-span T section continuous beams strengthened with BFRP and one comparative beam. Bearing capacity and failure mode of each beam is studied. The results show that yield load,ultimate load,and ductility of strengthened beams are remarkably increased and improved.

INFLUENCE OF BRAIDED FORMS ON TENSILE STRENGTH OF THREE-DIMENSIONAL FULL FIVE-DIRECTIONAL BRAIDED COMPOSITES

ZHONG Chong-yan, CAO Hai-jian1, LI Juan

2013, 0(2): 8-12.

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Glass fibers were used as raw materials to weave three-dimensional full five-directional braided fabrics by using three-dimensional braiding machine used with automatic module-combination rotation method. Braiding forms of 1×1,1×2,1×3 and 2×2 are included,and the four braided fabrics were then compounded with epoxy matrix to form three-dimensional full five-directional braided composites. Tensile properties were tested by using universal material testing instrument (Instron) and the influence of braided forms on the tensile properties of the composites were investigated. The results show that the tensile property of braiding form 1×1 is the highest,and that of braiding form 1×3 is the lowest. The braiding form 1×2 makes the best use of single yarn strength,while the braiding form 1×3 makes the worst.

STUDY ON THE STABILITY OF THE COMPOSITE LAMINATES WITH ONE-SIDE BONDED REPAIR

GUO Yan-jiang, HUANG Jun, MENG Zhi-jun, HE Wei

2013, 0(2): 13-16.

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In this paper,Three-dimensional finite element analysis models based on MSC. Patran are created in order to calculate the bucking factor of the repaired laminates. The effects of repair parameters (the patch radius, the thickness of patch etc.) on the stability of repaired structures are discussed in detail. Some conclusions are shown as follows: The critical load of the structure do not increase linearly with the parameter of the patch. The most stable situation happens when the patch thickness is about 40% ～ 60% of the laminate thickness. For the composite laminates with stiffeners,since the stiffeners can receive loads,the stability of laminates with stiffeners is more excellent than that of laminates without stiffeners.

MODIFICATION OF EPOXY RESIN WITH MALEIC ANHYDRIDE AND SODIUM HYDROGEN SULFITE

LI Peng, ZHANG Xue-mei, CHENG Bin, YANG Xiao-ping

2013, 0(2): 17-21.

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Epoxy resin was modified by maleic anhydride, then reacted with sodium hydrogen sulfite to attach sulfonyl group on it. The effects of reaction temperature,catalyst amount,the concentration of raw materials,and the ratio of mixed solvents on the synthesis process were investigated experimentally during the process of epoxy resin modified by maleic anhydride. The side reaction which produces cross-linked molecular will be significantly enhanced with increasing temperature,concentration of catalyst and raw material. When solvent ratio of methylbenzene and acetone is relative low,acid value is hard to monitor and side reaction with cross-lined products is enhanced, which is not conducive to the reaction. In further reaction with sodium hydrogen,structure of product is examined through elemental analysis to monitor,and particle size distribution of the according modified epoxy emulsion is monitored by Size Distribution Modal Analysis. Particle size of self-emulsifier aqueous dispersion system prepared under optimal conditions is about 100nm,which also shows great stability.

THE EFFECT OF STOICHIOMETRIC RATIO OF EPOXY AND AMINE ON THE MECHANICAL PROPERTY OF EPOXY/CURING AGENTS FABRICATIONS

WANG Peng, SUI Gang, YANG Xiao-ping

2013, 0(2): 22-27.

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Epoxy/curing agents fabrications play an important role in a variety of industria fields. Using curing agents with different molecular structure and different quantity can influence the networks of epoxy resin,and further influence the mechanical properties of epoxy/curing agents fabrications effectively. To investigate how the quantity of different curing agents influence the property of epoxy and carbon fiber composites,we use 2 different kinds of aromatic amine curing agents DETDA、DDS with different quantity of them. The different molecular structure and quantity of the curing agents will result in modulus change of the epoxy resin. Test different epoxy/curing agents fabrications using soxhlet extracts, tensile strength test,DSC and DMA method. The results reveals that the reaction activity of DDS is lower than DETDA,and the tensile property,T_g and ILSS of composites of DDS curing system are generally better than DETDA curing system of the same r. In both of the 2 curing systems,with the increasing of r, which is ranging from 0.5 to 1.25, the tensile modulus of resin decrease while the tensile strength increase. And T_g decrease after an increasing. In both 2 systems, it reaches the highest T_g when r=0.75. At the same time, the ILSS of composites decrease while the modulus of resin matrix decrease in both 2 curing systems. The failure modes of composites translate from matrix failure to interface failure as matrix modulus increase.

INFLUENCES OF TEMPERATURE AND HUMIDITY ON POLYETHER-BASED POLYURETHANE CURING QUALITY

LU Wu-gang, WANG Jun

2013, 0(2): 28-33.

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In order to study the influences of temperature and humidity on cured products of two-component polyether-based polyurethane used as resin matrix,its curing reaction kinetic equation and the surface foaming rate of its products cured at different temperature and humidity were studied and charactered by use of differential scanning calorimetry (DSC) instrument and polarizing microscope analysis software. The liquefied methylene diphenyl diisocyanate and polyether polyols were used as materials. The results show that, the curing reaction order,n,apparent activation energy,E,and frequence factor,A,equals 0.87, 43.59kJ/mol,and 2.344×10⁵s^-1 respectively. When temperature and humidity are below 25℃and 60%,the cured PU products have a low foaming rate, small foams and relatively smoother surface.

THERMAL OXIADATIVE DEGRADATION KINETICS OF SILICON-ARYLACETYLENE-CONTAINING RESIN

CHI Tie, QI Hui-min, HUANG Fa-rong, DU Lei

2013, 0(2): 34-38.

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Silicon-arylacetylene-containing resin (PSA-R) offers excellent high-temperature resistance,low dielectric constant,high-temperature mechanical property and easy processability. The kinetics of the thermal oxidative degradation of silicon-arylacetylene-containing resin was investigated by thermogravimetric analysis (TGA) under air. The thermal oxidative degradation of PSA-R had three different processes: thermal oxidation of unsaturated chain,thermal oxidative degradation of end-,side-chain scission and main-chain. The corresponding kinetic parameters include activation energy,pre-exponential factor and empirical order of the thermal oxidative degradation stages were evaluated by using Ozawa and Kissinger metnods,respectively.

RESEARCH ON THE TENSION-TENSION FATIGUE PERFORMANCE OF GLASS FIBER REINFORCED PLASTIC

MEI Duan, WANG Jun, LI Jun-ming, SI Hong-xiao

2013, 0(2): 39-42.

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The author prepared GFRP Specimen by way of vacuum assisted resin infusion process,using vinyl ester resin,epoxy resin and glass fiber as raw material in this paper. Through the dynamic fatigue test,this paper analyzes the influence of stress amplitude,layer mode and resin system on the tension-tension fatigue performance of GFRP. The result show that the tensile modulus of the GFRP decreased monotonously along with the increasing of the stress amplitude. Furthermore,the tension-tension fatigue performance of GFRP will be significantly decreased as the number of layers increasing. In addition,the fatigue performance of composites with epoxy resin matrix is significantly better than the one with vinyl ester resin matrix.

FINITE ELEMENT ANALYSIS OF FUNCTIONALLY GRADED MATERIALS BASED ON LAYERING METHOD

HUANG Li-xin, YAO Qi, ZHANG Xiao-lei, YANG Ming

2013, 0(2): 43-48.

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Based on layering method,finite element model is used to analyze a plane structure of functionally graded materials (FGMs). The FGMs plane structure is divided into a certain number of homogeneous layers with the material property between adjacent layer varying in a functional manner and the conventional homogeneous element can be employed to mesh the plane structure for its analysis. Numerical example shows that the stress and displacement results by finite element method (FEM) are satisfactorily agreed with the analytical solutions. By designing Young's Modulus nonhomogeneity parameters of material component Y-TZP in three cases,the influence on the FEM solutions is discussed. Numerical results demonstrate that the increase of nonhomogeneity parameters has effects on the FEM solutions of stress and displacement and the effects on stress are more than those on displacement.

A METHOD OF AERODYNAMIC PARAMETER CALCULATION USED FOR THE MATERIAL SELECTION OF WIND TURBINE BLADES

CHEN Li-xin, YAN Lei, CUI Yan

2013, 0(2): 49-51.

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Using Fluent software,we study the coefficient of lift and drag of NA 63-210 airfoil and obtain a fitting curve which changed by the angle of attack by Matlab. Through the analysis and comparison,we verify the feasibility of the method and obtain a basis of selection of the material of wind turbine blades.

RESEARCH ON THE RELATIONSHIP MODEL BETWEEN THE POROSITY OF C/C PREFORM AND PERFORMANCE OF C/SIC COMPOSITES FABRICATED BY GASEOUS SILICON INFILTRATION

LIU Wei, LIU Rong-jun, CAO Ying-bin, YANG Hui-yong

2013, 0(2): 52-56.

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A model used to in search of the relationship between the porosity of C/C preforms and the constitute of C/SiC composites was established and validated,where the C/SiC composites was fabricated by the gaseous silicon infiltration process with the C/C preforms possessed different porosities. The results showed that the value derived from the experiment in accord with predicted ones mostly. With the increase of porosity of C/C perform,the density of C/SiC composites also increased at first and then decreased after a critical value,so are the mechanical properties and phase content which derived from XRD analysis. The main reason for the deviation between the model and experiment is the un-totally reaction of pyrolysis carbon.

ANALYSIS AND RESEARCH ON DYNAMIC TEST OF WIND TURBINE ROTOR BLADE

SA Hao-liang, LI Cheng-liang, YU Qi-ming, CHENG Chun

2013, 0(2): 57-59.

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Dynamic test is an important method to verify rotor blade's fatigue life. This article analyzes and discusses some problems in blade dynamic test,especially about vibration mode,the relationship between vibration amplitude and vibration times. Feasible solutions in actual operation are also been proposed.

STUDY ON MECHANICAL PROPERTIES OF HYBRID FIBER REINFORCED CONCRETE

LI Yan-fei, YANG Jian-hui, DING Peng, ZHAO Hong-bing

2013, 0(2): 60-64.

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Fiber concrete is widely used in the engineering with its small plastic deformation,high strength and larger toughness. But as a result of the different scale and performance of different fibers,the influence of mechanical properties on concrete is different. So the experiments of macro-synthetic fiber,polypropylene hybrid fiber,hybrid fiber on the compressive strength,splitting strength and flexural strength are researched in this paper,which are compared with the mechanical properties of common concrete. Results show that the compressive strength,splitting strength and flexural strength of fiber reinforced concrete has been greatly improved than ordinary concrete,and the strength of hybrid fibers has been increased more significantly than single fiber reinforced concrete. The strength of hybrid fibers and steel fiber are not significant,so steel fiber can be completely replaced by the hybrid fibers in the project application with its low cost,good dispersion and weak corrosion.

RESEARCH OF FLAME-RESISTANT AND MECHANICAL PROPERTIES OF POLYESTER FIBER

GAO Wei-wei, CAO Hai-jian, QIAN Kun, CHENG Yong-gang

2013, 0(2): 65-68.

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In this paper,it uses microencapsulated red phosphorus which are the flame retardants and nano-SiO₂ which are the flexibilizers to manufacture flame-retardant polyester fiber splines by melt blending method,and study the effect of the amount of flame retardants and tougheners to the flame-resistant and mechanical properties of polyester. The results showed that microencapsulated Red Phosphorus can significantly enhance the flame retardant properties of polyester fibers splines,and nano-SiO₂ can improve the mechanical properties of the polyester fiber splines; When the content of microencapsulated red phosphorus was 5%,the polyester fiber splines exhibited a LOI value of 33,tensile strength of 17.99MPa,flexural strength of 26.75MPa,and impact strength of 1.97kJ/m²,and the mechanical properties of the materials declined seriously. When the content of microencapsulated red phosphorus was 3% and the content of nano-SiO₂ was 2%,the polyester splines exhibited a LOI value of 29,tensile strength of 35.51MPa,flexural strength of 31.54MPa,and impact strength of 2.03kJ/m².

STUDY ON TENSILE PROPERTIES OF CARBON NANOTUBES/ACIDIFICATION GRAPHENE HYBRID MATERIALS AND THEIR EPOXY RESIN COMPOSITES

JIA Yu-chen, YU Ke-jing, QIAN Kun, CAO Hai-jian

2013, 0(2): 69-73.

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The multi-walled carbon nanotubes (MWCNTs) and grapheme nanoplatelets were oxidized by the vitriol/nitric acid,and then the carbon nanotubes/graphene hybrid materials were prepared through the ultrasonic function method by the π-stacking interactions between the MWCNTs and graphene. Finally,we dispersed the carbon nanotubes/graphene hybrid materials into epoxy resin system to study the effect of the hybrid materials on the tensile properties of epoxy composites. The FTIR experimental results indicated that the hybrid materials were prepared and the acidification on the carbon nanotubes and graphene were successful resulting increasing the functional groups. The results of tensile tests showed that the addition of carbon nanotubes/graphene hybrid materials in epoxy resin can effectively increase the toughness and strength of the epoxy resin. Moreover,the tensile strength and toughness of the epoxy resin composites were gradually increased by the addition of the carbon nanotubes/graphene hybrid materials.

RESEARCH IN THE PERFORMANCE OF LFT-D CARBON FIBER REINFORCED NYLON

WANG Jing, ZHU Hai-feng, GAO Hong-mei, GAO Guo-qiang

2013, 0(2): 74-76.

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Through the LFT-D-CM (long fiber reinforced thermoplastic direct composite molding) process to produce CFRP (carbon fiber reinforced engineering plastics),the process greatest reserves the length of the carbon fiber of products,compare with the GFRP (glass fiber reinforced engineering plastics),and CFRP mechanics performance is better than that of GFRP,the material mechanical properties increased by the fiber content increased, online recycling waste can solve the recycling problem of carbon fiber reinforced thermosetting composite material, reduce energy consumption and pollution.

RESEARCH AND PERPATION OF THE INSULATING MATERIAL USED FOR LAMINATED BUSBAR

WANG Xian-quan

2013, 0(2): 77-79.

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An insulating material coated on the PET film,the PI film,or the NOMEX paper with epoxy adhesive is introduced in this paper. The material is mainly used for adhesion and insulation of laminated busbar. All properties of the has excellent electrical properties,adhesive strength and good manufacturability,can satisfy the requirement of laminated busbar insulating material.

THE FINITE ELEMENT ANALYSIS AND EXPERIMENTAL RESERCH OF AXIAL COMPRESSION PROPERTIES OF THE COMPOSITES CONICAL SHELL

DONG Wen-wu, WANG Peng-fei

2013, 0(2): 80-83.

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The finite element analysis of the composites conical shell are worked by the ANSYS finite element software in this paper,mean while,the conical shell axial compression test is worked by the mechanical testing machine. Establish the relationship between the finite element analysis and experimental research by comparing the finite element analysis and experimental results. The result indicated that the finite element analysis results consistent with experimental results to a certain extent. The finite element analysis can play a guild role in the experiment research.

TO EXPLORE TROUBLESHOOTING METHORD OF 40 LITERS OF A CERTAIN JYPE OF FUEL

DONG Wen-wu, YUAN Kun, PENG Hui

2013, 0(2): 84-87.

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The failure reasons of a certain type of fuel regulator 40 liters during the common plant commissioning process was analyzed in this paper. Corresponding troubleshooting method was proposed,which was verified by practical application.

CAUSE ANALYSIS OF FAN CYLINDER VIBRATION OF INDUSTRIAL COOLING TOWER AND SOLUTIONS

LIU Wen-hong

2013, 0(2): 88-89.

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In this paper,through the analysis of fan cylinder vibration cases,expounds the reason of vibration, and through the the two successful examples of solving the vibration problems,introduce the importance of the cooling tower air flow test and simulation software to solve the vibration problem. Based on these means,develop different solutions such as structure design and reasonable air flow rate for the vibration problem of FRP cylinder.

THE RESEARCH OF THE HEAT TRANSFER PERFORMANCE WHEN ETHYLENE GLYCOL SOLUTION USED IN THE CLOSED COOLING SYSTEM ANTIFREEZE

ZHANG Lin-xin, SHEN Yan, LIU Jing-nan, ZOU Yan-fang

2013, 0(2): 90-93.

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In the winter,ethylene glycol solution usually used in the closed cooling system instead of water as the antifreeze. Due to the changes in physical properties,its heat carrying capacity and convective heat transfer coefficient has declined. Based on the theory of closed-tower design,we studied the influence of the heat transfer different concentrations and different seasons to the Ethylene Glycol solution used in the closed cooling tower circulation; supposed that use a large diameter-thin walled tube,increase the flow rate of Ethylene Glycol solution cycle working fluid or increase the amount of ventilation rate,and reveals the variation in the different operating modes.

APPLICATION TENDENCY OF ADVANCED COMPOSITE MATERIALS FOR MILITARY UNMANNED AERIAL VEHICLES

HE Nan, YANG Jia-bin, GAO Feng

2013, 0(2): 94-97.

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The fundamental properties and application advantages of advanced composite materials were presented. In particular,the application requirements,development statuses and research frontiers of advanced composite materials for military unmanned aerial vehicles were emphatically discussed. In addition,some key problems,including low-cost manufacturing technology,structure/design integration technology and damage tolerance evaluation technology,were comprehensively analyzed.

SURVEY ON ENGINEERING STRUCTURE REINFORCING METHOD

ZHANG Chun-sheng, YAN Bao-shan

2013, 0(2): 98-101.

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With the increasing use of time, the environmental erosion and impact of various types of disasters,or due to the changes in the structural function, the design and construction errors and many other reasons, that result in engineering structures' structural performance can not continue to meet the functional requirements, so it needs to carry out the necessary repair and reinforcement. Through reading the large amounts of data, the research about components' bending, shear and compressive properties and application results of the engineering were summarized, the current reinforcement technology's advantages and disadvantages were analyzed, the direction of future research was put forward,and provide reference for related research.

THE DEVELOPMENT OF RECYCLING TECHNOLOGY OF COMPOSITE SCRAP

XU Wei, YUAN Kun

2013, 0(2): 102-105.

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In this paper,three methods of composite scrap recycling technology including mechanical recycling, thermal recycling and chemical recycling were introduced. The current development of the fluidised bed,pyrolysis, and solvent solution of the chemical technology to recycle and reuse composite scrap at domestic and abroad were briefly elaborated. Under the guidance of the policies of china,new technologies of low power consumption and high recovery of fiber should be greatly developed to recycle and reuse composite scrap.

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