COMPOSITES SCIENCE AND ENGINEERING

RHEOLOGY ANALYSIS OF EPOXY RESIN WITH TWO AVAILABLE CURING AGENTS

SONG Qiu-xiang, GUAN Xiao-fang, JIA Zhi-yuan

2015, 0(3): 5-10.

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The rheological behavior and exothermal behavior of an epoxy resin system with two available curing agents RIMH 037 and RIMH 038 were studied. The isothermal viscosity and actual exothermal behavior were analyzed for this resin system with six different curing agent mixture ratios. A viscosity model was established after the simulation of the obtained rheological data. The results show that under the same mixture ratio, the pot life was first increased and then decreased as the temperature increased, with 35℃ for the longest. Under the same temperature, the pot life was not obviously changed as the content of RIMH 038 increased. The change law of the pot life indicated by the actual heating test was consistent with the rheological analysis results.

STUDY ON THE FLAME RESISTANCES OF THE REACTIVE PHOSPHORUS-CONTAININGFLAME RETARDANT TO UNSATURATED RESIN

CHENG Liu-feng, WANG Jun, LIU Wei

2015, 0(3): 11-14.

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A reactive phosphorus-containing fire retardant, 2-hydroxyethyl methacrylate phosphate (HEMAP), was added to the unsaturated resin to improve its flame retardant properties. The cured unsaturated resin reached limiting oxygen index of 32.5 as added 5 parts of HEMAP. Thermal properties of unsaturated resin were studied by means of TG and DTG. Decomposition temperature of 10% mass loss and maximum weight loss both dropped with the increase of HEMAP from 0 to 20 parts by weight. However, formation of phosphorus-containing acid from decomposition of P-O-C bonds inhibited effectively further decomposition of the unsaturated resin. As the HEMAP content increased, the char yield increased from 3.8% to 31.4% at 800℃ in N₂ atmospheres, and the carbonaceous char yield increased from 0 to 4 at 500℃ in air atmosphere. The glass transition temperature (Tg) was measured by dynamic mechanical thermal analysis (DMA). The Tg of different unsaturated resins increased from 120.9℃ to 122℃ after added 5 parts of HEMAP.

MECHANICAL PERFORMANCE OF KENAF/ARAMID FIBER BLENDEDFABRIC REINFORCED COMPOSITES

WANG Chun-hong, JIA Rui-ting, BAI Su-yue, XU Lei

2015, 0(3): 15-19.

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In order to explore the effect of the four different blend ratios of kenaf/kevlar on the mechanical properties of blended fabric reinforced composites, the mechanical properties of composites reinforced by epoxy resin matrix, fine processing kenaf and aramid woven fabrics of different blending ratios were tested, and the morphology and polarity of kenaf fibre were examined by SEM and FTIR. The results show that kenaf/aramid 30/70 reinforced composites have the maximum flexural strength of 248.81MPa, and improved by 4.9%, flexura modulus of 12.91GPa, and improved 7.1%, compared with pure kevlar fabric reinforced composites. The maximum shear strength of kenaf/aramid 20/80 reinforced composites are 24.58MPa, increased by 18.6%. SEM and FTIR results indicate that the kenaf fiber became fine after treatment, fiber surface roughness was increased and the polarity became lower, which improves the interfacial bonding strength of the fabric with a resin, and improves the flexural and shear properties of aramid composites.

OPTIMIZATION DESIGN OF COMPOSITE DRIVE SHAFT OFFILAMENT-WINDING BASED ON ANSYS

ZHONG Hai-feng, HE Qin-xiang, ZU Lei

2015, 0(3): 20-25.

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In recent years, with the concept of the lightweight automotive deeply rooted, CFRP is expanding the range of applications in the automotive filed. The automotive drive shafts is very important in car. It has so significant huge economic value that we designed it by using composite materials both for its theoretical research and engineering applications and the environment and enhance the upgrading of domestic automobile manufacturing industry in transition. In this paper, we first make the finite element model, then, the basic factor that is winding angle, winding layers, winding thickness of the drive shaft. The method of optimization is ANSYS parameter design language and SUBP and first-order optimization method of ANSYS. The purpose of this paper is to optimize automotive drive shaft and make its winding angle and winding thickness better and make it lighter, higher strength.

STUDY ON MODIFIED IMIDAZOLE/EPOXY CURING SYSTEM

LIU Tu-yuan, WANG Jun, SHEN Hui, HU Yan-zhi

2015, 0(3): 26-30.

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In this paper, the curing reaction kinetics equation of modified imidazole/epoxy was studied through the DSC to get a view of the influnence of the differernt content of modified imidazole on the Tg of the resin with DSC and DMA. At the same time, the reaction mechanism was studied by infrared analysis. The results showed that the Ea of modified imidazole/epoxy resin system is 60.21kJ/mol and frequency factor A is 2.459 ×10⁷s^-1; the Tg of the modified imidazole/epoxy increased with the increase of modified imidazole first, then reduce with it. The maximum is 163.3℃ when the content is 4%. Modified imidazole deblock and isocyanate react with the hydroxyl groups during the curing process.

FINITE ELEMENT ANALYSIS OF FRP BURIED DOUBLE-WALL OIL STORAGE TANK

LIU Yong, LIU Wei-sheng, NAN Yang, ZHANG Ting

2015, 0(3): 31-34.

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The glass fiber reinforced plastic (FRP) double-wall tanks not only have long life, good anticorrosion property, self-weight light, free maintenance and other advantages, but also can effectively monitor oil leakage by installing continuous monitoring system in the sandwich of double-wall. Although the FRP buried double-wall tank has been widely used in foreign countries, but the design and research about this product is very lag in China. For this reason, the finite element model of FRP buried double-wall tank was built by using the ABAQUS/CAE module and the three-dimensional design software SolidWorks, and the stiffness and strength of this tank under the load in accordance with UL1316 standard were also calculated and analyzed. This article aims to analyze the reliability and applicability of FRP buried double-wall tank on filling station construction.

STUDY THE PROGRAM-DRIVEN MODELING METHOD OF THE OPTICAL FIBER WINDING

FANG Zhou, CAO Yan

2015, 0(3): 35-39.

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Complex fiber is wound on the spindle that is the main production of the composite fiber winding package. During the winding production, the uneven tension, axial movement and the internal thermal stress are the defect resources. It needs to simulate the winding package that the shape size and the internal thermal stress can be calculated. For the winding production simulation, provided the program driven method based on the cylindrical curve equation and computer three dimension (3D) graphics transformation to calculate the coordinates of structure point quickly. And then, in the 3D design environment the center line of winding model is built. The center line is used to build the winding model by the modeling operation. Meanwhile, the problems such as the coordinate optimization of construct point, the curve segments splice and the automation assembly are solved. These problems are caused by the reason that the fibers are moved from the winding layer to the next layer or across the winding circle. The experimental results show that the method can be applied to the generation of the adhesive layer defect model for any length with multiple defects and the accumulative axial error of a single layer is no more than 1.5 times of the fiber diameter.

STUDY ON THE ADDITION OF PS MICROSPHERE TO THE DIELECTRICALAND EMI PROPERTY OF THE ELECTRICAL COMPOSITE

LI Jin-jing, WANG Jun

2015, 0(3): 40-44.

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This paper studied the addition of microspheres on the conductivity, dielectric properties and electromagnetic shielding properties of carbon black/epoxy resin composites. When the carbon black volume fraction was 36vol%, the volume resistivity value reach the lowest value of about 169Ω·cm, the density of the composite was 120kg/m³, the maximum shielding effectiveness was 12.18dB, the maximum dielectric loss was 0.48, and the maximum imaginary part of the dielectric constant was 12.58. After adding microspheres. When the carbon black volume fraction was 36vol%, the volume resistivity value was 121.1Ω·cm, the density of the composite was 80kg/m³, at the corresponding frequency, the maximum shielding effectiveness was 15.44dB, the maximum dielectric loss was 1.46, and the maximum imaginary part of the dielectric constant was 20.52. Therefore, the addtion of the microspheres not only reduce the density of the material, but also greatly improve the conductivity, dielectric properties and shielding properties of the carbon/epoxy composite.

PREPARATION AND PROPERTIES OF QUARTZ FIBER REINFORCEDPOLY(SILYLENE-ARYLACETYLENE) RESIN COMPOSITES

DAI Dan-wei, ZHANG Li-quan, DENG Shi-feng, ZHOU Yan

2015, 0(3): 45-49.

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In order to reinforce the mechanical properties of quartz fiber reinforced poly(silylene-arylacetylene) resin (QF/PSA) composites, the paper changed the structure of fabrics and the diameter of quartz fibers to study their impacts on the mechanical and electrical properties of the composites. QF/PSA composites were prepared by compression molding with five kinds of quartz fiber fabrics, including 3D vertical-crossed woven fabrics, 3D face-core woven fabrics, 3D curved shallow-crossing linking fabrics, 2D structure woven fabrics and 2D twill fabrics (woven by 7.0μm and 7.5μm). The effects of the woven structure and the fiber diameter on the mechanical and electrical properties of the composites were studied by testing the flexural strength, flexural modulus, interlaminar shear strength (ILSS) and dielectric constant. The results show that the mechanical properties of the composites which are reinforced by 7.0μm quartz fibers are better than those of the 7.5μm quartz fibers, and the mechanical properties of QF/PSA composites with 2D fabrics are better than those with 3D fabrics. Meanwhile, these changes of the woven structure and the fiber diameter do not impact the electrical properties of the composites.

EXPLORATION OF WIND TURBINE BLADE′S BONDING AREADETECTING USING ULTRASONIC TECHNIQUE

AN Jing, XU Yu, ZHANG Shu-li, XIE Cun-cun

2015, 0(3): 50-53.

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It is difficult to detect and locate the internal defects in bonding area of the wind turbine blade accurately by traditional methods, such as visual inspection and tapping test, while their development will lead to the breakdown of blades and cause a potential failure of wind energy plants. In this paper, a kind of nondestructive detecting technique, called Ultrasound-Echo, is applied to detect and localize the defects in the glass fiber reinforced plastic (GFRP) bonding area between spar-cap and shear web. The result of scanning analysis shows, the thick sound attenuating GFRP laminate could be penetrated by ultrasound and echo information of the bonding area could be obtained. Therefore, the application of this method in non-destructive inspection of wind turbine blades has certain feasibility.

AN APPLICATION OF CARBON NANOTUBES IN DELAMINATIONDETECTION OF ANGLE-PLIED LAMINATES

LI You, HUANG Zheng-ming, WANG Ke-yong, CHANG Jun-hua

2015, 0(3): 54-58.

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In this paper, carbon nanotubes were dispersed uniformly into vinyl ester resin at a concentration of 1wt% by ultrasonic to form a conductive resin. Continuous glass fibers were then impregnated with the conductive as well as non-conductive resins to fabricate combined electricity conductor and electricity resistant angle-plied laminates. So a conductive network was formed along the width direction but not through the thickness. Four-layer 20°, 30° and 40° angle-plied laminates under tensile load were studied. By measuring and observing a jump variation in the resistances of the conductive laminate, a delamination initiation load level of the laminate under a uniaxial tension at a specific position was determined. Two distribution ways of conductive and non-conductive resin were used, and both of them could reach the aim of detecting the delamination initiation. But the jump did not always appear, because the delamination might not destroy the conductive network. The all-conductive laminates was also tested. The jump was not that obvious as the laminates with both conductive and non-conductive resins.

HOT-DIAPHRAGM FORMING OF THERMOSETTING CARBON WOVEN FABRICCOMPOSITE WITH C-SHAPED STRUCTURE

WANG Yong-jun, YANG Kai, CHEN Sen-lin, ZHAO Guo-qiang

2015, 0(3): 59-65.

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The process of hot diaphragm forming for thermosetting carbon woven fabric composite with C-shaped structure is introduced in detail. The coefficient of frictional slipping between layers of the prepreg (CYCOM970/PWC-T300)were measured under 60 to 120 degrees with 10 degrees increment. And, the curing experiments of hot-diaphragm formed components were carried out in oven and autoclave. Furthermore, the values of slipping angle, thickness and springback of C-shaped structure formed by hot diaphragm forming were obtained by means of 3D laser scanning. In addition, the porosity ratios were determined by section scanning.

INFLUENCES OF TEMPERATURE AND HUMID HEAT ENVIRONMENT ON MECHANICALPROPERTIES OF GLASS FIBER REINFORCED COMPOSITE

GAO Quan-xi, ZHENG Wei, KONG Ling-mei, QI Yan-yan

2015, 0(3): 66-69.

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Samples of glass fiber reinforced composite are prepared by vacuum aided resin transfer molding process, and the influences of temperature and humid heat environment on mechanical properties of glass fiber reinforced composite are evaluated. The results show that, the aggregation state of the resin changes from glassy state to elastic state with the increasing of temperature during -50~150℃, and the mechanical properties of glass fiber reinforced composite decrease. Similarly, the mechanical properties also decrease with the increasing of test time in humid heat environment. This phenomenon is suggested to be caused by the damage of interface between resin and fibers. This study provides technological support for the engineering-application of glass fiber reinforced composite.

STUDY ON AN UNSATURATED POLYESTER RESIN CURING SYSTEM

LIU Fang-fang, YUAN Xue-hui, FENG Qian-nan

2015, 0(3): 70-72.

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In order to solve the problem about the curing speed slow with the extension of gel time in the cure reaction of the unsaturated polyester resin (UPR), the UPR was cured with redox curing system which consisted of methyl ethyl ketone peroxide, cyclohexanone peroxide, cobalt bitter and 2,4-pentanedione at room temperature in this paper, hydroquinone was regarded as an additive at the same time. The amount of each component in the redox curing system on the influence of UPR gel time, peak time and exothermic peak temperature were studied, whereby the most suitable dosage of each component which including methyl ethyl ketone peroxide, cyclohexanone peroxide, cobalt bitter, 2,4-pentanedione and hydroquinone was obtained. And, UPR has long induction period, fasted curing in the late, and cure degree high when applying this technology condition which got through the experiment in the engineering application.

DESIGN OF COMPOSITE COMPONENT MOLD FOR U-SHAPE GIRDER

HAN Pei-pei, MENG Qing-jie

2015, 0(3): 73-77.

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The three-dimensional software CATIA was used to design the composite component mold of autoclave forming and optimize the mold structure for the composite component U-shape girder. During the digital design process, the influential factors about thermal expansion coefficient, the molding structure, spring-back angle compensation, the composite structure demolding are considered. The mold of frame convex structure is made of Q235 ordinary carbon steel by welding, modifying the mold surface in order to eliminate or decrease the deformation and adding the spring-back angle (about 1degree) to guarantee the mold surface dimensional accuracy. The mold has reasonable structure, higher processing quality, lower cost, good sufficient stiffness and strength, and gas permeability. And, the tolerance of surface dimension can meet the manufacturing request. The composite component U-shape girder is manufactured by using the designed mold. The results show that the tolerance of surface dimension and the controlling of angle deformation meet the technical condition and assembly request.

EXPERIMENTAL STUDY ON THE DURABILITY OF GFRP BARS UNDER MARINE ENVIRONMENT

LIU Xiao-yan, WANG Yi, WANG Xin-rui, XU wu-jun

2015, 0(3): 78-82.

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Accelerated aging test under seawater, alkaline solution and alkaline+seawater solution(solution mixed with seawater and alkaline) at 60 ℃ was carried out to investigate the mechanical performance of GFRP bars under marine environment. Solution mixed with seawater and alkaline was selected in dry/wet and stress/corrosion conditions. Tensile tests and SEM method were used to study the durability and corrosion mechanism of GFRP bars under different conditions. The test results show that alkali ion has the largest influence to the durability of GFRP, because the chemical reaction between silicon-oxygen bond of fiber and water molecule or hydroxide ion lead to silicon-oxygen bond rupture,and promote the formation of hydration product. But in accelerated aging test, the degradation of tensile strength of GFRP bars immersed in alkaline+seawater solution for 6 months is nearly 30%, and the degradation of elasticity modulus is 12%. GFRP bars show good anti-corrosion performance under dry/wet and stress/corrosion conditions, the tensile strength and elasticity modulus retention is both nearly 90% under the two conditions.

STUDY ON THE PROPERTIES OF THREE-DIMENSIONAL SEWED SANDWICHSTRUCTURAL DAMPING COMPOSITE MATERIAL

HUANG Jing-feng, LUO Han

2015, 0(3): 83-86.

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In this article, 3-dimensional sewed sandwich composite is made by using flexible epoxy resin and different reinforcing materials, providing better damping performance and higher structural strength. By testing each performance of the 3D sewed sandwich damping composite, it is concluded that: for 3D sewed structure, it is best to use epoxy resin composite for structural layer and aramid fiber reinforced polymer (AFRP) for damping layer to reinforce the flexible epoxy resin, which provides a damping ratio of 3.33%, bending modulus of 14.3GPa, bending strength of 290MPa, and impact toughness of 338kJ/m².

RESEARCH PROGRESS OF MICROCAPSULES USED IN SELF-HEALING POLYMER MATERIALS

WANG Qing, LI Hai-yan, CUI Ye-xiang

2015, 0(3): 87-91.

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Self-healing material is a new kind of smart materials, the microcapsule embeded in the material is a method to realize the self-healing, and it is also one of the hotspots in this field. This paper introduces the concept and principle of microcapsule type self-healing, summarizes the development of DCPD microcapsules, epoxy resin microcapsules, silicone oil microcapsules and other microcapsules type self-healing in recent years, and emphatically introduces the latest research results, and the prospect of microcapsules type self-healing materials.

Industry information contents

2015, 0(3): 92-128.

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