COMPOSITES SCIENCE AND ENGINEERING

THE DEVELOPMENT OF A NEW TENSION CONTROL SYSTEM FOR AUTOMATED FIBER PLACEMENT MACHINE

HAN Zhen-yu, WANG Zhi-bin, LU Hua, FU Hong-ya

2014, 0(5): 4-8.

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Automated fiber placement is an important composite fabrication process, in which fiber tension is an important process parameter to affect the quality of the products. This paper develops a closed-loop tension control system which uses DSP as the control unit, tension brake and low-friction cylinder as the execution unit, linear displacement transducer as the feedback unit. The mathematical model is established, while the hardware and software platform of the tension control system is set up. Works on constant tension, tension step response and speed step response were carried out based on the proposed platform. Experimental results show that the proposed tension control system responses fast and the tension fluctuation rate is low, which could satisfy the requirements of the tension control for fiber placement.

RESEARCH OF FBG-BASED COMPOSITE MATERIAL MOLDING AND IMPACT MONITORING

WU Xue, LI Wei

2014, 0(5): 9-12.

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Carbon fiber composite (CFRP) is an advanced composite material that has been widely used, but internal delamination damage can easily occur when suffering an external shock due to its weak interlayer performance, which will result in mechanical properties declination and security risk. This paper considers embedding the fiber Bragg grating sensor (FBG) in carbon fiber composite laminates to monitor the RTM molding process and the impact response of CFRP plate under low-energy impact. Experimental results show that FBG can effectively monitor the temperature and strain variation during the molding process, and reflects the presence of residual strain. The strain variation and internal injuries within the composite can be monitored at low energy impact conditions. This work help to build a basis for low-energy impact damage.

STUDY ON THE INFLUENCE OF ALUMINUM ALLOY′S STRENGTHENING RANGE ON INTERFERENCE FIT OF PULTRUDED COMPOSITE MATERIALS AND ALUMINUM ALLOY

LI Fei, DENG An-zhong, ZHAO Qi-Lin, ZHANG Dong-dong

2014, 0(5): 13-19.

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In order to study the influence that aluminum alloy's strengthening range has on interference fit of aluminum alloy and pultruded composite materials, first of all this paper simplified the constitutive relation of the aluminum alloy as a bilinear model, and then worked out the relation between magnitude of interference and normal stresses on aluminum alloy and composite material interfaces via elastic-plastic mechanics. After that, it conducts verification through finite element and experiment, where the constitutive relation of the aluminum alloy is simulated through multi-linear isotropic strengthening (MISO). At last, the influence that the strengthening range has on normal stress is studied, and it concludes that (1) theoretical solution and finite element solution coincide well with the experimental values, which demonstrates the correctness of the theoretical derivation; (2) considering aluminum alloy strengthening range during interference fit of composite material and aluminum alloy, an even larger normal stress can be obtained on aluminum alloy and composite material interfaces; (3) during interference fit, non-uniformity of composite tube wall poses less influence on normal stresses of the interface, hence the influence non-uniformity of the tube wall has on the interference fit can be neglected.

THE CONSTRUCTION OF THE THREE-DIMENSIONAL ORTHOGONAL ORGANIZATION MODEL OF WOVEN FABRIC BASED ON UG SECONDARY DEVELOPMENT

YAN Chun-yun, GUO Xing-feng

2014, 0(5): 20-24.

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The purpose of this paper is to quickly and accurately establish the overall orthogonal organization model and easy to expression orthogonal woven fabric interwoven structure. On the basis of analysis of the overall orthogonal structure features, five parameters such as fabric layers (warp layers+weft layers), the number of warp columns and weft columns, the number of stitching yarn and the way of stitching are proposed to represent the overall orthogonal organization. Assuming the form of warp, weft and stitching yarns in ideal orthogonal organization, using the giant element body, the yarn cross-sectional dimension calculation was established. The model of the yarn and the orthogonal organization cad design program is written in the development environment provided by UG/Open GRIP. The overall orthogonal organization model can be quickly and accurately established by entering the necessary parameters. The model is not only able to clearly characterize the structure of the fabric, but also to calculate fabric fibers volume content and the thickness of the fabric.

STUDY OF MECHANICAL PROPERTIES AND HEAT RESISTANCE OF EPOXY RESIN MODIFIED BISMALEIMIDE COMPOSITES

WANG Ju-lin, WANG Jun

2014, 0(5): 25-31.

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In order to study the properties of epoxy (EP) resin modified bismaleimide (BMI) resins, four kinds of epoxy resin: AFG-90, TDE-85, E-14 and D-17 modified BMI resins were prepared. BMI and EP modified BMI resins were processed into prepregs with carbon fiber (CF) grid cloth. The prepregs were made into composites through laminated molding. The infrared absorption spectrum of cured resin system was tested. The curing curves of unmodified and four EP modified resins and the glass transition temperature (T_g) was tested by DSC. The bending strength and impact toughness of the samples were test by a universal mechanical test machine. And the damaged morphology were observed and recorded by SEM. The results indicate that the EP and BMI are cured on different temperature with good compatibility. It was found that the enhancement of TDE-85 group was best, and the D-17 has the best toughening effect which fits the strengthing and toughing rules. The T_gs of AFG-90,TDE-85,D-17 were higher than 200℃, which suggests that EP modified BMIs did not sacrifice their heat resistance.

INFLUENCE OF THE ANTI-RADICAL EFFECT OF CARBON NANOTUBES ON THE MECHANICAL PROPERTIES OF COMPOSITES

CHEN Hong-yan, HUANG Hua-bo, WANG Ji-hui

2014, 0(5): 32-36.

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Carbon nanotubes (CNTs) were incorporated into glass fiber (GF)/vinyl ester resins (VER) composites to improve their mechanical properties. However, when 0.4, 0.8, 1.2wt% CNTs were added into the composites, the interlaminar shear and longitudinal compressive strengths which were belong to the matrix-dominanted properties decreased from 52.32MPa and 258.34MPa to 45.14, 50.11, 42.14MPa and 240.99, 257.87, 235.27MPa, respectively. This indicates that the CNTs possessed an against effect to free radicals, resulting in the inhibition of the radical curing reaction of vinyl ester resin. A higher temperature initiator BPO was used to eliminate this negative effects from CNTs. Finally, the interlaminar shear and longitudinal compressive strengths of the CNTs/GF/VER composites increased to 63.25, 70.35, 60.57MPa and 299.12, 318.54, 280.11MPa, respectively. Meanwhile, the Dynamic Mechanical Analyzer (DMA) gave a consistent result, which confirmed the against effect to free radicals from CNTs.

BLADE LOADS CALCULATION FOR MW WIND TURBINE

ZHUANG Heng-dong, HUANG Hui-xiu, XU Yang

2014, 0(5): 37-40.

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It′s very important to estimate and analyze components′ loads of wind turbine, because it runs in hostile environment. This review maily introduces load sources and load sorts for rotor blade and load calculation method. Then, a 6MW carbon blade was taken as an example to calculate the extreme and fatigue loads using the GH bladed software.

STUDY ON CALCULATION METHODS OF SHEAR CAPACITY CONTRIBUTION OF FRP STRENGTHENED CONCRETE BOX BEAMS

ZHANG Peng-yang, YAO Yong, YANG Yong-xin, ZHANG Yan-hong

2014, 0(5): 41-45.

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The shear capacity calculation methods of the RC beam strengthened with FRP at present were introduced. Considering the influence of distribution of the oblique crack of concrete box girder on FRP strain distribution and the influence of the lateral deformation of the web on the bonding performance of the interface of FRP with concrete, the method for the determination of the average effective strain of concrete box beam strengthened with FRP, and the calculation method for the shear capacity contribution of FRP of the strengthened concrete box beam were proposed. Through the comparison with the experimental results, the calculation results of the method proposed in this paper are in good agreement with experimental values.

TENSILE TEST FOR TWO KINDS OF JOINTS BETWEEN CARBON FABRIC ROD AND METAL END

YANG Li-wei, LI Zhi-lai, DONG De-yi, XIN Hong-wei

2014, 0(5): 46-50.

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At present,truss structures are used in most of the space camera structure. Generally, truss structures are composed of benches, truss rods and ends. Most of truss rods are made of carbon fabric composites, and most of ends are made of metal. There are two kinds of modes of joints between carbon fabric rod and metal end: bonded joints and bonded-pinned joints. In order to compare the strength of the joint between bonded joints and bonded-pinned joints,two kinds of tensile samples are designed and manufactured based on current requirements. Then, tensile test was done. The results show that: the maximum tensile load that bonded joints can bear was 42.25kN, joints strength was 5.83MPa; the maximum tensile load that bonded-pinned joints can bear was 42.10kN, joints strength was 5.81MPa. Compared to bonded joints, bonded-pinned joints did not distinctly increase joints strength, but the strength was reduced merely. Test results lay the foundation for subsequent research.

STUDY OF THE EFFECTS OF PROCESSING CONDITIONS ON VOID DEFECT IN CARBON FIBER/EPOXY COMPOSITES

CHEN Chao, ZHANG Ya-ting, GU Yi-zhuo, ZHANG Hua-ting

2014, 0(5): 51-55.

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A experimental simulation system for composites in hot pressing process was established for studying void formation evolution. By means of this system, the effects of molding pressure, pressure applying moment, bleeding mode and sample thickness on void were investigated. The results indicate that the simulation system can be used to obtain the relationship between void and processing factors. For MT300/603 carbon fiber/epoxy prepreg, increasing molding pressure and decreasing pressure applying temperature can reduce porosity and void size, and the molding pressure is more obvious for eliminating void. Moreover, resin flow plays an important role in void elimination mechanism rather than pressure squashing and venting effects. Thickness of prepreg stack has significant effect on void formation. These results provide important studying method and experimental evidences for void defect control in composites for hot pressing process.

PREPARATION AND STUDIES OF PROPERTIES FOR EPOXY RESIN-BASED BMC

CHAI Hong-mei, DAI Hai-tao, DING Yong-gang

2014, 0(5): 56-58.

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Epoxy resin-based BMC was prepared by mixing glass fiber, fillers, bisphenol A and bisphenol F blends. The curing process and mechanical properties were studied. The influence of different mass ratio of bisphenol A/bisphenol F resin and fillers types on tensile properties were discussed. The results show that when the mass ratio of bisphenol A/bisphenol F is 1∶1, and SiO2 filler, epoxy resin-based BMC had the best properties.

STUDY ON THE PREIMPREGNATION PROCESS OF HOT-MELT PREPREG

HAN Cheng-zhi, ZHENG Yi-meng, LING Hui, CHENG Lei

2014, 0(5): 59-63.

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The processing parameters of impregating temperature,clearance of roller,velocity in manufaturing hot-melt prepreg of carbon fiber/epoxy have been studied with hot-melt prepreg machine of 300mm width. Several problems in the preimpregating process were analyzed. And the optimum process parameters were obtained as follows:preimpregating temperature:100~105℃,preimpregating velocity:4~5m/min,interval of pressure roller:380~400μm,temperature of cooling plate:about 16℃,winding tension:300N/m.

APPLICATION OF GLASS FIBER REINFORCED PLASTIC ON THE DESIGN OF LIGHTWEIGHT PASSENGER BRIDGE

XIONG Hui-zhong, SHAN Wei, WANG Ping, ZHANG Da-yong

2014, 0(5): 64-68.

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Due to the advantages such as lightweight, high-strength, damping, anti-corrosion, glass fiber reinforced plastic (FRP) has been widely used in bridge engineering severing in extreme environment. This work designed a 10m+10m span passenger bridge which mainly employs the pultrusion FRP, and verified its mechanical response to the static load, free vibration and earthquake impact load by the finite element method. The results show that the bridge has low weight, with high safety margin and the natural frequency of vibration, and can effectively shorten the construction period of the scene. The analysis results in this paper would be a certain engineering significance for the FRP bridge design.

THE OVERALL DESIGN AND MANUFACTURE TECHNIQUES OF WIND POWER BLADE MOLD

YAN Chen, LI Xiao-ling, LI Yi-quan

2014, 0(5): 69-74.

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Based on the experience on large composite wind power blade mold of Sinomatech Wind Power Blade Co., Ltd., wind power blades mold design and manufacture technology are introduced in detail. At last, some problems on mold design and manufacture are discussed.

ANALYSIS ON THE EFFECT OF SUPERVISION ON GLASS FIBER REINFORCED PLASTICS MORTAR PIPES QUALITY CONTROL

HE Ping, ZHANG Li-ping, YANG De-xu, ZHANG Lin-wen

2014, 0(5): 75-78.

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According to the performance characteristics of FRPM, illustrated by the case of Baiyang River diversion project in Tacheng area, the paper introduces the quality control method of FRPM in production and install process, analyzes the effect of supervision in water project, propounds the long-term performance test proposal for FRPM.

DESIGN ON HYDRAULIC REVERSAL SYSTEM FOR WIND TURBINE BLADE MOULD

YANG Shuai, YIN Xiu-yun, HU Wen-jie, GUO Wen-tao

2014, 0(5): 79-81.

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In the production process of large-scale wind power blade production, the control of blade mould hydraulic turnover action plays a vital role in the quality of the productand life. So during the production process, stringent requirements are proposed for the synchronization and reliability of blade mold opening and clamping flips.This articlemainly introduces the hydraulic and electrical control systems of large-scale wind turbine blade multiple turnover mechanism. Key content such as oil cylinder action characteristics and electrical control in the mold turning process is analyzed in detail. The control system can better solve the control problems such as the synchronization and reliability of large-scale wind turbine blade mold flip process in practical applications.

RESEARCH PROGRESS OF FRP STRENGTHENED MASONRY STRUCTURE

ZHANG Bo

2014, 0(5): 82-86.

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The application of FRP composites in strengthening field for masonry structure is presented, and the progress of the shear, seismic, bond behavior between masonry and FRP of the masonry structure reinforced by FRP is introduced in detail, which provides the reference for the design and construction of masonry structure reinforcement and masonry structure reinforcement.

PROGRESS AND DISCUSSION ABOUT REPAIR AND AIRWORTHINESS SUBSTANTIATION COMPOSITE STRUCTURE IN GENERAL AIRCRAFT

YANG Wen-feng

2014, 0(5): 87-91.

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The wide application of advanced composite structures brings about a great many advantages for general aircraft. However, it also generates various kinds of damages and the later repair problems during usage. The airworthiness substantiation and appraisal after maintenance has been the key to keep the validity and compliance of repairs, and the qualification approval to maintain/restore the intrinsic availability and safety of aircraft. Based on the difference contrast of European/American and Chinese in commercial composite material application and maintenance field, including the technical level status, the engineering application accumulation, and achievements etc., this paper aims to point out that China should prospectively consider the basic theories and key technologies involved in airworthiness substantiation and appraisal of civil aircraft composite material application and maintenance. Works should be carried out to provide technical reservation and independent intellectual property rights for airworthiness substantiation and appraisal of composite repair for the imported commercial aircraft (above repair manual), general aircraft and domestic commercial aircraft.

Industry information contents

2014, 0(5): 92-128.

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