Table of Content

28 January 2009, Volume 0 Issue 1

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BASIC STUDY

INVESTIGATION OF DAMAGE MECHANISMS OF PE/PE LAMINATES
BY ACOUSTIC EMISSION TECHNIQUE

WANG Xu, ZHANG Hui-Ping, YAN Xiong

2009, 209(1):  3-6. 

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The main purpose of this paper is to investigate the acoustic emission (AE) property of PE/PE laminates as well as tensile rupture mechanism AE signals were processed by the method of clustering and discriminance From the discussion, the conclusion can be listed as follows: the main reason of macrodamage is that lots of and different kinds of microdamages were generated simultaneously According to distribution of AE signals, early micro damages with large number and small energy mainly come from interface and matrix, then damage grade increased and accompany with a little bit fiber fractured, finally, main damages with small number but large energy mainly come from fiber fractured together.

THERMOELASTIC BENDING OF FUNCTIONALLY GRADED
 MATERIALS BEAMS UNDER THERMAL LOAD

WANG Ming-Lu, Ma-Wen-Lei, Wei-Gao-Feng

2009, 209(1):  7-9. 

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The material properties of FGM beams are assumed to vary continuously through the thickness of the eam according to a power law distribution.The mathematical model and its corresponding variational principle for FGM elastic beams are set up on the basis of the assumption that plane section remains plane and normal to the beam axis.With the help of the analytical solution and Ritz solution，the deflection and the stress distribution are discussed，in which the phenomena of stress overturn is found.

NONLINEAR MICROMECHANICS ANALYSIS OF COMPOSITES

ZHOU Zhu-Lin, YAO Hui, LIU Jian

2009, 209(1):  10-14. 

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 Composites  have obvious nonlinear behavior on offaxis tensioncompression and shear.There are several reasons for this:①nonlinear behavior of matrix；②rotation of the fiber；③crack of matrix gradually.This paper presents micromechanics analysis for nonlinear behavior of composites.Theoretical values are in agreement with that of experimental results.This theory can be applied for strength analysis of multidirection composites.

STUDY ON NATURAL FREQUENCY OF PLAIN WOVEN FABRIC LAMINATE WITH CUTOUT

LI Ding-He, WANG Xuan, FENG Zhen-Yu, XU Jian-Xin

2009, 209(1):  15-18. 

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The existence of the cutout has a great effect on the structural mechanical performance. Dynamic mechanical characteristics of inplane woven composite laminates with one edge simply supported are studied by means of the experimental in this paper. Based on MSC.Patran, a finite element model is developed to study the free vibration response of square inplane woven composite laminates having an eccentrically. An attempt is made to gain a complete understanding of the effect of a circular or elliptical cutout on natural frequencies of the laminate. The results show that natural frequencies gain from means of experimental tallies with finite element model. The effect of circular cutout on natural frequencies is equivalent approximatively to elliptical cutout whose long axis parallel specimens length in whole cutout size range. When the elliptical cutout size or eccentricity ratio is under a val

RESEARCH ON LOWENERGY IMPACT OF AIRCRAFT COMPOSITE MATERIAL
BASED ON INFRARED THERMAL IMAGING TESTING

ZHENG Li-Qing, DAI Yong-Chao, YANG Xiao-Lin, XIAN Ming-Le

2009, 209(1):  19-22. 

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The antiimpact capability of aircraft composite structure is very important.In this paper,according to study the familiar impacting source,by the technique of falling body impact experiment and infrared thermal imaging testing，the typical lowenergy impact damages of aircraft composite material were simulated and studied.The main form and characteristic of the damages were got by the study.

MATERIAL RESEARCH

EFFECT OF ACIDIFICATION TREATMENT ON THE PROPERTIES OF CARBON
NANOFIBERS AND COMPOSITES

MEI Qi-Lin, Yuan-Lu, Wang-Ji-Hui, Huang-Zhi-Xiong

2009, 209(1):  23-27. 

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Concentrated acidification (vitriol/nitric acid) method was applied to the surface treatment of carbon nanofibers (CNFs).The carbon nanofibers/epoxy resin composites were fabricated under hydrothermal and ultrasonic conditions.Xray photoelectron spectroscopy analysis showed that hydroxyl and carboxyl functional groups，which could participate in the cure reaction of epoxy resin，were introduced into the surface of carbon nanofibers after acidification treatment.Rheology properties tests indicated that the fluidity of composite fluid was improved.Results of fracture toughness tests and scanning electron microscope (SEM) exhibited that the interface combination between the carbon nanofibers and the resin was effectively improved and the fracture toughness of composites was remarkably increased after acidification treatment.

 STUDY ON THE MODERATE TEMPERATURE
 CURING EPOXY RESIN SYSTEM FOR RESIN TRANSFER MOLDING

CHAI Hong-Mei, WANG Lei, LV Jin-Yan

2009, 209(1):  28-30. 

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In this paper, the epoxy resin system was prepared by applying liquid amine to the modified epoxy resin,which was the mixture of CYD128 and epoxy A. The results showed that the viscosity of the resin system was 255cps at 30℃. It was the moderate temperature curing epoxy resin system. And the tensile strength, tensile module, flexural strength, flexural module of the cured resin product were 67.7 MPa, 3.1GPa, 101MPa and 2.87GPa respectively. The system can meet the requirement of RTM.

RESEARCH ON CONTINUOUS BASALT FIBER AND ITS REINFORCED COMPOSITE MATERIAL

ZHENG Jin-Dong, ZHANG Xin-Gang, YANG Yong

2009, 209(1):  31-33. 

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By analyzing the component and fiber forming process of continuous basalt fiber effect on its performance,and studying the composite material made from the basalt fiber of Hengdian Group Shanghai Russia & Gold Basalt Fiber Co., Ltd., the current situation of study and manufacture in home were concluded, and the application prospects were predicted

THE PREPARATION OF MODERATETEMPERATURE CURING EPOXY
 RESINS USED AS HOTMELT PREPREG

LI Ming-Qi, Li-Peng, Yang-Xiao-Ping

2009, 209(1):  34-37. 

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Moderatetemperature curing epoxy resins used as hotmelt prepreg were prepared by adding acrylamide.The relationships among viscosity，gel time and temperature，as well as the curing technology of resins were determined.Meanwhile，the mechanical properties of the composites were studied.The results showed that the viscosity of resin systems decreased with increasing the contents of acrylamide resulting in good impregnation of reinforced fibers.The mechanical properties of such composites were better than those of composite without acrylamide.SEM analysis demonstrated that the interfacial adhesion between fiber and resin was excellent.

EFFECTS OF FLEXIBLE AMINE T403 ON THE MECHANIC PROPERTIES
AND CROSSLINKING DENSITY IN EPOXY SYSTEMS

CAI Hong-Yang, Li-Gang, Liu-Hai-Yang

2009, 209(1):  38-41. 

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Epoxy modified by a flexible amine (T403) was prepared by casting molding method. The effects of T403 contents on the static and dynamic properties and fracture surfaces of epoxy casts were studied. The relationships between effective average molecular weight of the network chain (Mc) and the mechanical properties of epoxy casts were investigated. With increasing the content of T403, the tensile and flexible strength decreased, while the impact strength increased, which demonstrated that the toughness of epoxy could be improved effectively by T403. SEM analysis showed that the roughness of fracture surfaces of epoxy casts increased with the addition of T403. The theoretical Mc was larger than that of effective Mc, which indicated the complexity of curing reaction.

STUDY ON POLY (LACTIC ACID)/STARCH COMPOSITE FOAMS (Ⅰ):
STUDY ON FOAM TECHNOLOGY

YUAN Hua, ZHAO Qiu-Feng, LIU Zhi-Yong, REN Jie

2009, 209(1):  42-46. 

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PLA/starch composite foams were prepared by reactive extrusion and the influences of the content of starch、AC、maleic anhydride、BPO and screw speed on the properties of the foams were discussed. The results showed that the starch content was better to be lower than 20%, or it would have unfavorable effect on foamability. AC content should be 3phr~4phr, MAH and BPO could improve the compatibility of the composite system so that foam performance was improved, screw speed should be kept in 100rprm~200rpm.

STUDIES ON MODIFICATION OF PHENOLIC RESIN BY CTBN

XU Xin-Feng, WU Zhan-Peng, WU De-Zhen, JIN Ri-Guang

2009, 209(1):  47-50. 

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Phenolic resin was modified by carboxyl terminated butadieneacrylonitrile (CTBN) to improve its toughness. The effect of CTBN content on mechanical properties of the modified phenolic resin was discussed. Results showed that the tensile strength and elongation at break of the phenolic resin increased with the increase of the content of CTBN. When the content of CTBN was 10%, the mechanical properties reached the maximum. The structure and properties of the modified phenolic resin were characterized by SEM,FTIR and TGA respectively.The results proved that chemical reaction happened between phenolic resin and CTBN，and the heat resistance of  modified phenolic resin decreased.

BENDING PROPERTIES OF MULTILAYERED BIAXIAL WEFT KNITTED FABRIC
 REINFORCED COMPOSITE

WANG Wen-Yan, JIANG Ya-Meng, LIU Liang-Sen

2009, 209(1):  51-53. 

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The paper mainly studies the bending properties of multilayered biaxial weft knitted fabric reinforced composite. The inserted yarns are glass fiber and UHMWPE fiber, there are three kinds of fabrics for reinforcement，which are fabrics made of glass fiber, UHMWPE fiber and fabric made of the two kinds of fibers. The resin employed is VE. The research results show that this kind of composite bears excellent bending properties, the transversal property of composite that include glass fiber are particular. The breakage of glass fiber is brittle, but UHMWPE is flexible.

EQUIPMENT PROCESS

PROPERTIES OF A NOVEL AROMATIC DIAMINE CURING AGENT

FENG Xin-Xian, Wang-Yao-Xian, Cheng-Shu-Jun

2009, 209(1):  54-57. 

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A novel diamine 2，2bis(3amido4hydroxy)phenylpropane (HAPP) was prepared by nitrifying and reduction reactions of Bisphenol A.The curing behaviors of system composed of this new curing agent and epoxy resin was studied by means of the gel property of the system and differential scanning calorimeter (DSC).The curing reaction activation energy of HAPP/Epoxy calculated by Kissinger and Ozawa methods were 4230 kJ/mol and 4668 kJ/mol respectively，and the cure reaction followed firstorder kinetics.These results show that HAPP containing hydroxyl and phenyl exerts an influence of autocatalysis on the curing system.HAPP is able to lower the activation energy and curing temperature of the system.With HAPP as curing agent，the epoxy resin matrix composites reinforced with aramid fibre cloth exhibited excellent mechanical properties and their interlaminar shear strength，flexural strength and tensile strength are 341MPa, 375MPa and 380MPa respectively.

THE ANILINEPOLYVINYL ALCOHOL MICROEMULSION ELECTRIC
 CONDUCTION COATING DEVELOPMENT AND PERFORMANCE TEST

ZHONG Ping, HUANG Jian-Jun

2009, 209(1):  58-61. 

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Used the oxypolymerization method to synthesize soluble poly aniline/polyvinyl alcohol（PAn/PVA)compound electric conduction coating.Studied the influence of the aniline content, reaction time, temperature and acid concentration on the compound electric conduction coating conductivity, determined the better polyreaction condition. Meanwhile tested its stability, electrical conductivity, mechanics and surfacetexture. The result indicates PAn/PVA conduction coating has good stability,  the highest conductivity of paint coating may achieve 4.57s/cm, the adhesion of coating can be significantly improved by epoxy resin.

MECHANICAL PROPERTIES OF PANELS OF COCURED SANDWICH STRUCTURE

ZHAO Peng-Fei, ZHAO Jing-Li, HE Ying

2009, 209(1):  62-64. 

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Directing to needs about designing UAVs airframe and working out technological process, this article compares the mechanical properties of composite laminates and panels of honeycomb sandwich structure made from different kinds of prepregs at the same cure condition. It comes to the conclusion that cocure technique can be directly used to make honeycomb sandwich structure used for UAVs airframe. The results show that mechanical properties are basically about the same, but the shear strength of the panels is lower than the laminates obviously.

TECHNOLOGY AND PROPERTY OF PULTRSION FIBREGLASS REINFORCED
PLASTICS FOR GARDEN TOOL HANDLE

WANG Hui

2009, 209(1):  65-67. 

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In this paper,the technology of pultrsion FRP garden tool handle have been introduced, the influence of filling materials,fibre glass,mats,rapid and temperature on the property of products have been discussed.

FLEXURAL BEHAVIOR OF FRP PROFILE ASSEMBLED BOX BEAM

GE Chang, XUE Wei-Chen

2009, 209(1):  68-72. 

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The FRP profile assembled box beam is a box beam composed of pultruded cellular profiles that interlocking connected with other profiles through square tubes and togglebars. The FRP profile assembled box beam is a light, corrosionproof structural member and can be quickly fabricated and applied in short span highway bridges or pedestrian bridges. In this paper, a linear constitutive shell FE model was created and validated by existing laboratory testing to discuss the monotonic flexural behavior of the box beams. Moreover, parametric analysis was con

ANALYSIS ON THE FLEXURAL BEHAVIOR OF PARTIALLYPRESTRESSED
CONCRETE BEAMS REINFORCED WITH CFRP

TONG Gu-Sheng, LIU Yong-Qing, WU Qiu-Lan

2009, 209(1):  73-76. 

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The flexural experiments of 7 partiallyprestressed beams were conducted, and the ultimate bearing capacity, deflection and failure mode of the beams were analyzed The beams include 1 nonreinforced contrasting sample and 6 reinforced with CFRP ones.The breadth of the initial damage and the number of layer of CFRP were considered.The experimental results showed that the ultimate bearing capacity of the beams with CFRP increased clearly and the crack expanded more slowly than the contrasting beam This explained that CFRP could reinforce the capability of the partiallyprestressed concrete beams

REVIEW

RESEARCH ON PLASMA SURFACE MODIFICATION
OF ORGANIC HIGHPERFORMANCE FIBER

ZHOU Zheng-Gang

2009, 209(1):  77-79. 

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As a method of fiber surface modification，plasma surface modification takes the advantages of simple operation，high efficiency，energy source saving and nonpollution，which is research hotspot in recent years.This paper reviews the progress of the plasma surface modification method in research and development of the high performance fiber reinforced composites，points out the development trend.

THE DEVELOPMENT OF VACUUM ASSISTED RESIN INFUSION (VARI)

ZHAO Chen-Hui, ZHANG An-Cheng, ZHANG Yue-Zhou

2009, 209(1):  80-84. 

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VARI plays a very important role in affordable composites. The strongpoint, shortcoming, manufacturing, resin distribution system and its application at home and abroad are introduced in this paper. The summarization indicates that VARI which is a lowcost technology fabricating composites has been widely applied, especially for bigsize production. The development of VARI will reduce the cost of composites and widen the application of composites. In addition, accurate simulation of resin distribution is very important for VARI, but there is few related research at home. This means a lot of works need to be done.

ADVANCES IN DAMPING PERFORMANCE OF FIBER REINFORCED
POLYMERBASED COMPOSITE MATERIAL

TIAN Nong, XUE Zhong-Min, CHEN Chun, ZHANG Zuo-Guang

2009, 209(1):  85-88. 

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As fiberreinforced composite are more widely used in hightech field of aeronautics and astronautics, wind blade etc, the knowledge in damping of composites is becoming more important for controlling the noise and vibration in the structuresIn recent years,the researches on composite damping mechanisms and prediction methods have received extensive attention This paper reviews recent achievements in damping studies for fiberreinforced composites The content can be divided into three parts, such as damping mechanisms, study status, the effect of interface Finally, some recommendations regarding future research are prospected.