COMPOSITES SCIENCE AND ENGINEERING

STUDY ON MODIFIED THERMOPLASTIC POLYMER TOUGHENED TGDDM EPOXY RESIN

CAI Hao, WANG Ji-kui, WANG Yao-xian

2015, 0(7): 5-11.

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The modified thermoplastic polymer (MTP30) was used for tetraglycidyl 4, 4'-diaminodiphenyl methane (TGDDM) epoxy resin toughening modification. The pre-polymerization and curing reaction kinetics of TGDDM were studied with infrared spectrum and differential scanning calorimetry (DSC). The mechanism of curing reaction and toughening effects were discussed. The microstructure morphology was observed by SEM. The results indicate that by using 15phr MTP30 toughened TGDDM/MNA system, the elongation at break and impact strength of the casting were 7.19% and 15.6 kJ/m², respectively, while the heat distortion temperature and the glass transition temperature (Tg) only slightly decreased, and that MTP30 uniformly dispersed in TGDDM resin system, which shows obvious toughening effect.

RESIN MATRIX COMPOSITES SIMULATION AND ANALYSIS OF INTERNAL-EXTERNAL COORDINATION CURING

XU Jia-zhong, LI Shuang, QIAO Ming, YOU Bo

2015, 0(7): 12-17.

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In the traditional curing process of thick-walled shell winding, the inner temperature is often not enough to meet the requirement of its curing or time is too long, so it usually adopt molding process of many winding and much curing, high energy, low efficiency, which not only has greatly increased the cost, and as a result of layered of curing resin cross-linking, so difficult to guarantee the quality of the product. So the new internal-external coordination curing process is advanced in this paper and its principles are introduced. Two mathematical models including heat conduction model and cure kinetics model of fiber composite thick-walled shell of the internal-external coordination curing process are built. The finite element software ANSYS and APDL language are used to develop numerical simulation procedure of the process, the numerical simulation program of the internal-external coordination curing process is developed to study the distribution and the variation of temperature and curing degree. The numerical simulation of the new process shows that with external heating source temperature and preheating temperature, changing curve of temperature, curing and strain of center node is increased, and walled housing internal-external coordination curing time is shorted to 1/3 of the curing time of traditional method.

RESEARCH ON PROPERTIES OF A ABLATIVE MODIFIED PHENOLIC RESIN

LI Ting, LIU Jian-jun, YANG Xue-jun, ZHAO Wen-bin

2015, 0(7): 18-21.

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In this paper, a modified phenolic resin was studied, including viscosity property, heat resistance and ablative property. It is found that the viscosity of resin system is lower than 800mPa·s in the range of 60~120℃, process applicable period is longer than 150 mins at 70℃ and 80℃. The glass transition temperature is 253℃, carbon residue rate at 800℃ is 67.1% in the Nitrogen atmosphere, quality ablation rate and linear ablation rate are 0.0766g/s and 0.119mm/s. Carbon fiber needling preform reinforced the modified phenolic resin composite was made by RTM, its interlayer shear strength and axial compressive strength are 39.3MPa and 177MPa, respectively. The linear ablation rate and quality ablation rate are 0.044mm/s and 0.0762g/s. Experimental results show that this modified phenolic resin system, which has low viscosity, long process applicable period, good heat resistance and ablative property, can meet the requirement of RTM process well, and its carbon fiber needling perform composite has the potential of being used as ablation resistant material.

RESEARCH ON DESIGN OF FILAMENT WOUND COMPOSITE SQUARE TUBES

MU Jian-qiao, ZU Lei, WANG Ji-hui, LI Shu-xin

2015, 0(7): 22-26.

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As a class of rotationally asymmetric bodies, design of filament-wound composite square tubes demands both windability and uniform coverage of winding patterns. Based on the analytic geometry, the spatial relations between the feed eye and the mandrel were outlined and the kinematic equations for coupling the motion of the mandrel and the feed eye were derived. Consequently, a design method for small-angle geodesic winding of composite square tubes was proposed, taking the non-slippage condition of winding trajectories into account. A periodically geodesic winding theory was presented and its winding error for various initial winding points was analyzed. The designed fiber patterns were then applied to the practical production of a composite square tube with small winding angles. The results show that the present design method for filament-wound square tubes is accurate and reliable. The obtained kinematic equations and motion laws of the feed eye and the mandrel satisfy the basic winding principle and manufacturability of filament-wound composite square tubes.

PREPARETION AND PROPERTIES OF A NEW SILICON-POLYTRIAZOLE RESIN AND ITS COMPOSITE

GUO Bing, DU Lei, WAN Li-qiang, HUANG Fa-rong

2015, 0(7): 27-32.

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Low molecular weight silicon-containing arylacetylene (LPSA) was designed and synthesized from diethynylbenzene and dimethyldichlorosilane. A new silicon-polytriazole (Si-PTA) resin was synthesized from 4,4'-diazidomethyl biphenyl (DAMBP) and LPSA via 1,3-dipolar cycloaddition. The results show that the resin could be cured at 80℃. The dynamic thermomechanical analysis (DMA) results show that the glass transition temperature (Tg) of the cured Si-PTA resin is 310℃. Thermogravimetric analysis (TGA) results show that the thermal decomposition temperature (T_d5, temperature at 5% weight loss) under N₂ could reach 340℃. Unidirectional T700 carbon fiber reinforced Si-PTA composite (Si-PTA/T700) was prepared through compression molding. The structures and properties of the composite were characterized by mechanical property tests and DMA. The results show that the Si-PTA composite exhibited good mechanical and thermal properties.

THERMAL PHYSICS AND MECHANICAL PROPERTIES OF CNTs/TDE85 EPOXY COMPOSITES

YANG Qiao-xin, LIU Ling, WANG Xiao-lei

2015, 0(7): 33-38.

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CNTs were added into TDE85 epoxy and formed CNTs/TDE85 composites with various CNTs mass fraction by the aid of ultrasonic and centrifugal dispersion method. Electrical and thermal conductivity, and mechanical properties of the composites were measured. Results show that the electrical and thermal conductivity were improved by 10⁶ times and 17.2%, respectively, with a CNTs weight loading of 0.5%. The obtained percolation threshold was nearly 0.2% for the CNTs/TDE85 composites. Prediction from DM software have shown that the results with aspect ratio of 10~100 was coherent with the experimental result. The glass transition temperature (Tg), flexural strength and modulus were improved by 6%, 47% and 5%, respectively, with CNTs loading of nearly 0.5%.

AN EXPERIMENTAL STUDY OF 100kW BLADE WITH FLATBACK AND THICK AIRFOILS UNDER STATIC LOAD

XU Li-jun, XU Lei, YANG Ke

2015, 0(7): 39-44.

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Increasingly large-sized wind turbine blade brings many design and production problems, static experimental of blade is the important foundation and verification means, which can be used to analyze the structure stability of the blade. This paper presents the static experimental study of the 100kW experimental blade with flatback and thick airfoils, which was designed by project team. The bucking and strain behavior of flapwise and edgewise are analyzed. Performance of the blade, including buckling and strain under the action of load is investigated, the structural performance advantages are compared with the traditional blade with sharpedge and the blade with flatback. At last, the results of failure experimental are compared with the design value to analyze the error generation causes.

INFLUENCE OF ZrSiO₄ AND Al₂O₃ PARTICLE SIZE ON FRICTION AND WEAR PROPERTIES OF BRAKE FRICTION MATERIALS

WANG Yu-ling, YAO Guan-xin

2015, 0(7): 45-49.

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The purpose of this study is to investigate the effect of the alumina and zirconium silicate grain size on friction and wear properties of friction material. The fiber reinforced organic friction materials are prepared by the way of thermoforming, and the friction and wear performance are tested. The effect of zirconium silicate and alumina particle size on the friction and wear properties of multi-fibers rein-forced resin-based friction materials has been investigated. The results show that zirconium silicate and alumina play significant role in increasing friction coefficient. With decreasing fillers particle size, the friction coefficient decrease. But coefficient stability is the best when filler size is middle. And it has also been found that the coefficients of friction changes slightly with decreasing particle size. By observing the morphology of the sample surface after wear, and to explore the mechanism of friction and wear. The SEM micrographs show that the moderate size of alumina and zirconium silicate added to the friction material play a protective role on surfaces and can reduce the wear.

STRESS INTENSITY FACTOR ANALYSIS OF CENTER-CRACKED METALLIC PLATE BONDED WITH COMPOSITE PATCHES BASED ON THE FINITE ELEMENT METHOD

MU Zhi-tao, HAO Jian-bin, GAO Xue-xia, LI Xu-dong

2015, 0(7): 50-53.

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The stress intensity factor of the crack tip for the cracked plate repaired with composite patches is still the focus of attention. At present, the majority study of the stress intensity factor is about thin plate. Therefore, based on the finite element method, the model of center-cracked thick (10mm) metallic plate bonded with composite patches was established, and the stress intensity factor of the crack tips were calculated. Meanwhile, Rose's analytical model was used here to verify the model. The changes of the SIF values and the repair effect along the thickness direction were analyzed. The results show that the finite element solution is conservative; the difference between the maximum and the minimum of the SIF along the thickness direction is significant when the thickness of the repaired plate is larger; the double repair is much better than the single repair.

RESEARCH ON THE FRP HOLDING POLE FOR TRANSMISSION & TRANSFORMER ENGINEERING

YU Cheng, NAN Wu-jiang, CHEN Ling-fei, HAO Chun-gong

2015, 0(7): 54-57.

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FRP holding pole is a new kind of overhead transmission line tower lifting tool. This holding pole is mainly produced by carbon fiber composite materials. There are two kind of structure, including round type and lattice type FRP holding pole, which compared with aluminum alloy holding pole reduces weight by 50%~80%. The maximum stress is less than 200MPa, and the maximum deformation is less than 55mm. The FRP holding pole can be applied to the cliff, scarp and other dangerous terrains, reducing the labor intensity of woker, enhancing the efficiency of construction.

THE APPLICATION OF REMOTE TEMPERATURE MEASUREMENT SYSTEM ON WIND POWER BLADE IN THE CURING PROCESS

YIN Xiu-yun, YANG Shuai, CHEN Cui, GAO Er-qi

2015, 0(7): 58-62.

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This paper mainly introduces the general implementation proposal of temperature data acquisition and monitoring design for maximum 16 moulds in a single workshop.It is convenient and reliable to realize the remote monitoring for wind power blade curing temperature through the implementation.The acquisition data can be viewed as real time curve and history curve.And the data storage function will facilitate the comparison with production record data,for the real time record data is traceable.

STRUCTURAL DESIGN AND CONSTRUCTION OF INNOVATIVE FIBER REINFORCED POLYMER FENDER FOR INLAND WATERWAY BRIDGES

ZHU Lu, LIU Wei-qing, FANG Hai, ZHOU Ding

2015, 0(7): 63-68.

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Based on the upgrading of Changlixian channel, this paper developed one kind of fixed fiber reinforced polymer (FRP) fender. The ship collision force with and without FRP fender was calculated using ANSYS/LS-DYNA software. The FRP fender can be manufactured by vacuum assistant resin infusion process (VARIP) in the factory. With the combination of concrete filled steel tubular piles and the expansion bolts, the connection between FRP fender and bridge was solved. The results show that the maximum impact force can be decreased by 38.0% if the ship directly hits the head-on FRP fender instead of bridge in the transversal direction. With the side FRP fender, the maximum impact force can be reduced by 41.8% in the transversal direction and 29.3% in the longitudinal direction, respectively. Since it can greatly decrease the impact force, the FRP fender exhibits superior performance. It can meet the demands of upgrading the channel and effectively protect the bridge structure at the same time. Overall the FRP fender provides a new idea to design the anti-collision system for the inland waterway bridges.

EXPERIMENTAL RESEARCH ON THE EFFECT OF COMPRESSIVE STRAIN RATE OF GLASS FIBER REINFORCED PLASTIC RODS

HU Rui, WANG Jian-hui, YAN Hai-chun, LIN Da-lu

2015, 0(7): 69-72.

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In order to study the compressive property of GFRP rod, quasi-static compressive test and impact performance test are carried out, by adopting WAW600 microcomputer controlled electro-hydraulic servo universal testing machine and Φ37 split Hopkinson pressure bar (SHPB). GFRP rods show typical brittle failure instead of yield characteristics and plastic deformation in quasi-static conditions. The effect of strain rate is sensitive at the low speed of 100N/s to 500N/s. The slopes of ascending stress-strain curves, the peak stresses and the peak strains increase with the strain rate under the impact loading. The compressive strength increases greatly, and the dynamic load coefficient is large than 1.35, up to 1.58.

STUDY ON THE EPOXY RESIN AND CURING SYSTEM OF MID-TEMPERATURE PREPREG

YANG Si-hui, WANG Xiang, WANG Jun

2015, 0(7): 73-77.

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This paper studies an epoxy system which could be cured at mid-temperature and is suitable for the preparation of hot-melt method, focusing on the technological properties, storage performance of the resin system and discussing the curing mechanism of dicyandiamide/epoxy resin according to DSC and IR. The results show that when the ratio of dicyandiamide and substituted urea is 6∶3, the prepreg can be achieved with an epoxy resin cured at mid-temperature and at room temperature, and it will obtain a longer shelf life.

EXPERIMENTS RESEARCH ON THE ANCHORAGE PERFORMANCE OF CFRP TENDON IN DIFFERENT POTTING MATERIAL

ZHU Yuan-lin, LIU Li-hua, ZHANG Ji-wen, JIANG Ting-hui

2015, 0(7): 78-82.

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In order to find a better potting material to improve the anchorage performance of adhesive anchorage for CFRP tendons, the static load tensile tests on the behavior of adhesive anchorage for CFRP tendons were conducted. The test parameters include four different potting material, three different cone angles and five different anchorage lengths. The analysis results shows as follows: ①the anchorage length needs up to at least 50 times of tendon diameter in the Lica building adhesive; ②the Wirelock shrinkages in the process of solidification, which can't be used to straight type anchorage. But the Wirelock can anchorage CFRP tendon when the anchorage with 3 degrees angle; ③the strength of CFRP tendon drops to about 78.87% of the original strength in the high temperature solidification process of chilled cast potting material; ④the anchorage length needs to achieve 40 times of tendon diameter as the epoxy resin mortar is used to anchor CFRP tendon; ⑤in the same condition, the ranking of the elongation in the anchor interior is Lica building adhesive glue, epoxy resin mortar, chilled cast potting material and Wirelock wire rope glue, respectively.

THE DEVELOPMENT AND IMPLEMENTATION OF COOLING TOWER THERMAL PERFORMANCE TEST SOFTWARE

YIN Zheng, XU He-hua, ZHANG Li-xin, SHEN Yan

2015, 0(7): 83-85.

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A new type of cooling tower thermal performance test software based on C# language is introduced in this paper, including the software framework structure, the system function block and the way of implementation. At the end, the actual test results comparative analysis between this software and the Cooling Technology Institute of American is listed too.

REVIEW OF PRESSURE-RESISTANCE EFFECT OF CARBON FIBER REINFORCED POLYMER

XU Zhao-hui, ZHU Jian-feng, DING Yong, SUN Yuan-zhen

2015, 0(7): 86-90.

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Carbon fiber reinforced polymer (CFRP) is a kind of excellent new structural material, and also has good self-awareness. To explore the pressure-resistance effect (change of resistance along with the strain), the domestic and foreign research situation was reviewed on the pressure-resistance effect of different CFRP forms such as monofilament,tendon and layer, and the relevant research results were summarized about the sensitivity of pressure-resistance effect, the change law and mechanism were discussed. Finally, the further research for the application of CFRP materials was put forward to build intelligent structure system.

PROGRESS ON LEADING EDGE PROTECTION TECHNOLOGY OF WIND TURBINE BLADES

LU Jia-qi, MU Shu-xiang, LI Quan-zhou

2015, 0(7): 91-95.

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The safe and reliable operation of wind turbine blade is the basis of acquiring high wind energy utilization coefficient and large economic benefit of the wind turbine as it is the only component for capturing energy of wind turbine. Due to long period work of wind turbine blade in harsh environment, corrosion phenomenon prone to occur on blade leading edge. As the leading edge of blade tip is relative thinner and the linear velocity of the tip is the highest, the erosion on this part is the most serious in the whole blade. Leading edge erosion of wind turbine blade has big effect on wind energy production. With the development of large wind turbine, blade leading edge corrosion becomes an urgent problem to be solved in wind field. In this paper,the effect of wind turbine blade leading edge corrosion on wind turbine performance, the main factors cause blade leading edge corrosion, and the progress on leading edge protection technology of wind turbine blades are reviewed. The future focus on leading edge protection of wind turbine blades is proposed.

Industry information contents

2015, 0(7): 96-128.

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