COMPOSITES SCIENCE AND ENGINEERING

RETROSPECT AND PROSPECT OF DEVELOPMENT OF FRP/CM IN CHINA

XUE Zhong-min

2015, 0(1): 5-12.

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FRP/CM has evolved into an important precursor materials in the field of new materials, which is the basic and indispensable material for developing modern industry, national defense and science and technology. The paper mainly reviews the developments, the application status of FRP/CM industry in China, and looks forward to the future prospect of domestic FRP/composite.

EXPERIMENTAL STUDY ON COMPRESSION PROPERTIES OF PULTRUDED GFRP LAMINATES

DU Ao , LIU Yu-qing , XIN Hao-hui , ZUO Yi-ze

2015, 0(1): 13-17.

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To investigate the compressive mechanical properties and the failure mechanism of pultruded glass fiber reinforced polymer (GFRP) laminates, matrix resin and fiber mass fraction were regarded as variable parameters, and longitudinal and transverse compression tests were conducted on six kinds of GFRP laminates. Compressive mechanical properties and failure modes were compared and analyzed. The result shows that matrix cracking is the typical longitudinal compressive failure mode, while the typical transverse compressive failure modes are shear failure and matrix cracking. Specimens with epoxy matrix exceled those with vinyl matrix in compressive mechanical properties. Increasing longitudinal fiber mass fraction can improve the longitudinal compressive mechanical properties to a certain extent. But, the fiber with too high mass fraction will have adverse effect. Changing fiber mass fraction has little influence on the transverse compressive mechanical properties.

CNTs/Ni/REO COMPOSITES USED TO ENHANCE THE WAVE-ABSORBING PROPERTY OF SANDWICH STRUCTURE

HE Ya-fei, HAO Li-feng, YANG Fan, JIAO Wei-cheng

2015, 0(1): 18-22.

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Study the wave-absorbing property of sandwich structures by dispersing the carbon nanotubes, lanthanum oxide in nanometer scale, Ni powder in micrometer scale and ytterbium oxide in micrometer scale into epoxy and filling the interlayer of glass fiber reinforced composites sandwich structures with the above epoxy mixture. The wave-absorbing property was characterized by using vector network analyzer. The results show that these composites structures have a good performance in wave-absorbing. The reflection ratio(dB) and the wave-absorbing bandwidth are both improved. From 2.99 to 18.00GHz, there are three wave-absorbing peaks. The bandwidth (<-5dB) of the first peak is 2.55GHz, the maximum dB is -23.78dB, and it is located at 4.86GHz. The bandwidth (<-5dB) of the second peak is 3.75GHz, the maximum dB is -21.07dB, and it is located at 10.35GHz. The bandwidth (<-5dB) of the third peak is 5.66GHz, the maximum dB is -13.65dB, and it is located at 14.04GHz. The total wave-absorbing bandwidth (<-5 dB) reach 11.96 GHz, and it accounts for 80% of all the tested frequency. Besides, the wave loss ratio of the composites structures is improved as well.

MICROMECHANICS ANALYSIS ON FIBER/EPOXY MICRODROPLET BY MICRO-RAMAN SPECTROSCOPY-CARBON FIBER AND POLYETHYLENE FIBER

DENG Li-hui, CHEN Cong-jie, CHEN Shi, XIA Shao-xu

2015, 0(1): 23-27.

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The effect of geometry on interfacial micromechanical behaviors of fiber/matrix microdroplets is investigated by microbond test and micro-Raman spectroscopy.The interfacial micromechanics of single carbon fiber(CF)/epoxy microdroplet and polyethylene fiber (PE fiber)/microdropletare were investigated. The study indicates that interfacial edge angle can affect the stress distributions in the different fibers/matrix microdroplets.The residual stress distribution and axial stress distribution caused by applied load of different end angles for carbon fiber/epoxy interface are W-and M-shaped respectively. Whereas,those for PE/epoxy interface are M-and W-shape respectively. The stress transfer efficiency is 70% for carbon fiber/epoxy, but it is only 13% for PE fiber case. Furthermore, interfacial shear stress has been acquired, which presents an antisymmetric distribution. Shear stress concentration locates at the ends of microdroplet. And shear stress of carbon fiber/epoxy is larger than that of PE fiber/epoxy.

LOAD DISTRIBUTION AND FINITE ELEMENT ANALYSIS OF MULTI-FASTENER JOINTS T800 COMPOSITE LAMINATES

ZHANG Ming-xing

2015, 0(1): 28-32.

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Tension test were performed on multi-fastener joints composite laminates samples produced with T800 carbon fiber prepreg. Load-displacement curves of whole composite samples under axial tensile load were obtained, and strain-load curves were available through the strain flowers around the holes. The results show that the first and last rows fasteners carry the most load and the middle ones take the least load. The samples break on the area near the first row fasteners. The failure modes mainly are squeezed fastener hole and tensile failure. One finite element analysis model is established and verified with the high agreement between simulated and experimental results.

THERMAL-ELECTRICAL SIMULATION ANALYSIS OF AIRCRAFT COMPOSITE

ZHANG Bin, CHEN Xiao-ning, ZHAO Jin-long, HUANG Li-yang

2015, 0(1): 33-37.

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Composite material has many advantages such as small specific gravity, high strength and good corrosion resistance. So, it is widely used to the aircraft manufacturing industry. Whereas, composite material has a poor conductivity, making lighting current difficult to quickly go out when subjected to lighting. Resistance heat would cause serious heat damage and endanger the safety of aircraft flying. In this paper, the finite element analysis software is used to simulate the thermal-electrical effect of carbon fiber epoxy composite plates when struck by lighting. Simulation results show that maximum potential of the composite is consistent with the trends of the exposed lighting current waveforms, lighting current goes along with the direction of the largest conductivity of the surface the composite plates. Resistance heat generated by lighting current also mainly goes along the surface so that the thermal damage of the composite plate are concentrated on the surface. The paper obtains the thermal damage distribution of the composite plate when struck by lighting, and provides a reference for assessing the reliability of the composite exposed to lighting.

THE STRUCTURE DESIGNING AND FEM OPTIMIZATION OF COMPOSITE DUCT

ZHOU Xiao-min, WANG Guan-shi

2015, 0(1): 38-41.

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Duct propeller can increase the propulsive efficiency. Comparing to the metal ducts, the composite duct can effectively reduce the weight of duct propeller, which is critical for the use of duct propeller. Through the designing of ring longitudinal and ring ribs, the disadvantage of composite duct's stiffness could be overcome. Based on the ANSYS APDL optimization design theory, two best duct structures have been given with the objective functions of dry and wet modal respectively. Accordingly, the best structure has been present. Meanwhile, the similarities and differences of dry and wet modal features, including the nature frequency and mode shape. The results show that the first nature frequency of wet modal is about one quarter of the dry's value, while the mode shapes are almost the same. The designing of composite duct and the optimization method have certain directive meaning to the engineering design.

SIMULATION AND TEST FOR THE LIGHTNING DAMAGE OF THE GLASS FIBER COMPOSITES

ZHAO Jin-long, CHEN Xiao-ning, ZHANG Yun-sheng, ZHANG Bin

2015, 0(1): 42-47.

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Theoretical deducing, simulated lightning test and finite element simulation are used to investigate the mechanism and state of lightning damage of the aircraft composite sandwich panels. It provides the basis for the design of the aircraft lightning protection. The three-dimensional finite element model of the composite board is constructed through the thermal-electrical-mechanical multi-physics coupling field. According to the structure and the role process, the lightning effect of the aircraft composite is analysed to study the damage mechanism and the possible state of the composite plate that is struck by lightning. The impact current generator is used to carry out the simulated lightning test to observe the lightning effect of the composite panel. By comparing the test results and the simulation results, the effectiveness of the simulation approach and the correctness of the simulation results are verified.

RESEARCH ON MODELING OF MULTI-AXIAL WARP-KNITTED FABRIC IN WIND TURBINE ROTOR BLADE

TANG Jin-qian, ZHU Xiao-qin, LU Xiao-feng, ZHANG Deng-gang

2015, 0(1): 48-53.

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Modeling of multi-axial warp-knitted fabric in wind turbine rotor blade was studied in this paper. Modeling methods were verified by fiber failure calculation. Hence, multiple fiber failure criteria of composite were discussed first and a brief comparison of their advantages and disadvantages were made. The Puck criteria was described in detail and chosen for analysis. Two modeling methods--multi-layers with one layer for one direction, and one layer with equivalent simplified properties--were compared,and the final calculation results were the same. Both methods were proved to be acceptable accordingly. Thus, the simplified modeling can reduce the workload.

ACOUSTIC EMISSION MONITORING ON MODE Ⅱ DELAMINATION DAMAGE EVALUATION OF COMPOSITE MATERIAL

LI Ya-juan, ZHOU Wei, LIU Ran, ZHANG Xue-mei

2015, 0(1): 54-58.

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In order to study the damage evolution of interlaminar interface [0/0], [0/45] and [+45/-45] in composites material for wind turbine blades, mode Ⅱ delamination growth experiment of the composites has been conducted by means of acoustic emission technique. In this flexural experiment, real-time acoustic emission monitoring was used during the entire delamination process and the delamination growth. The results show that high speed crack extension, large delaminated areas and planar crack front are obtained for [0/0] layered composite specimen, and unstable crack extension is associated with high amplitude, long duration time acoustic emission (AE) signal. In the case of [0/45] and [+/-45] composite material specimen, delamination damage and extension are affected by the fibers along ±45 ° direction, and high AE cumulative hits before unstable crack extension, low crack propagation rate, small delaminated areas and irregular crack front are induced. The delamination damage evolution of the composites could be divided into two basic stages, the micro damage accumulation around crack tip region and delamination unstable extension.

EXPERIMENTAL RESEARCH ON THE INFLUENCE OF THE SHAPE OF MATERIAL TO RESIDENCE TIME IN A RECOVERY DEVICE OF CARBON FIBER COMPOSITES

SONG Jin-mei, LIU Jian-ye, ZHANG Cui-miao, PENG Yu-gang

2015, 0(1): 59-63.

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Fluidization curve of reactor and the influence of the shape of material to residence time have been studied with EPE foam as a tracer material on the basis of establishing experiment device of recycling carbon fibre using the oxygen pyrolysis method in order to ensure that recycled carbon fibre can be moved. The minimum fluidization velocity and carryover rate have been determined through calculating with formulas and analyzing fluidization curve from experiment. The experimental results show that the critical fluidization velocity and carry-over velocity of solids are 0.15m/s and 0.24m/s, respectively. The shape of material affects its residence time in fluidized bed. The residence time order from long to short of single shape materials is the cylinder, rectangle and sphere in turn in the fluidized bed; mixture residence time order from long to short is sphere and cylinder, sphere and rectangle, rectangle and cylinder mixture. Mixture of rectangle and cylinder or single sphere as pyrolysis material should be used to thermal test in order to discharge recycled carbon fiber as soon as possible.

THE STRAIN ANALYSIS OF SHEAR-STRENGTHENED DAMAGED RC DEEP BEAMS WITH EXTERNAL BF SHEET

LIU Hua-xin, SUN Ying-ming, WANG Xue-zhi, KONG Xiang-qing

2015, 0(1): 64-68.

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In order to study the change regularity of strain of shear-strengthened damaged RC deep beams with basalt fiber reinforced polymer (BFRP) sheets, six damaged RC deep beams were tested after being shear-strengthened using BF sheets. The failure process and failure mode of the six damaged RC deep beams were studied with different shear span ratio and different ways of paste. And, the strain distribution rules of BF sheets and concrete and the different factors that affect the strain distribution were also analyzed. It lays the foundation for the theoretical calculation analysis of shear-strengthened damaged RC deep beams.

FEM STRUCTURE DESIGN OF 10kV COMPOSITE TRANSMISSION TOWER AND THE APPLICATION STUDY OF ENGINEERING

LIU Huan-huan, ZHU Xiao-dong, KE Rui, YE Li-jun

2015, 0(1): 69-73.

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To solve the application problem of composite transmission tower, based on a 10kV transmission line project, the paper calculates a variety of loads of the transmission tower and build a mathematical model using ANSYS. At last, the experiment indicates that the mathematical model in this paper is credible.

THE MECHANICAL PROPERTIES OF HOLLOW MICROSPHERES/HDPE COMPOSITE MATERIAL

XIE Ya-fen

2015, 0(1): 74-76.

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Hollow microsphere surface was modified and hollow microspheres/high-density polyethylene composite material with different proportion were prepared by extrusion. This paper systematically studies the relationship of tensile strength, elastic modulus and elongation at break of hollow microspheres/high density PE (HDPE) composite material with content (wt%) of hollow microspheres. It has been revealed that the calculated out-come is in accordance with the actual measured value. The tensile strength is slightly decreased with raising content of hollow microspheres, while the elastic modulus is increased with raising content of hollow microspheres. When the content (wt%) of hollow microspheres was 15%,the elongation at break reached the maximum.

INFLUENCE OF SOLVENTS ON MECHANICAL PROPERTIES OF GLASS FIBER REINFORCED RESIN COMPOSITES

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

2015, 0(1): 77-81.

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Glass fiber reinforced vinyl resin composites were prepared by vacuum aided resin transfer molding process (VARTM). The influence of different solvents on mechanical properties of composite was investigated, and the fracture morphology was studied by means of scanning electron microscope (SEM), for mechanical property analysis. The results indicated that the prepared composites exhibited considerable corrosion-resistance behaviors, where the modulus of the composites nearly maintained its level after being immersed in the solvents for 180 days, while its bending strength or tensile strength slightly decreased by 5%~10%, due to the reduction of interface bonding strength, showing neglectable influence on their mechanical performances. All of these results provided the technical supports for the engineering applications of composites.

A RESIN TRANSFER MOLDED(RTM) PROCESSING METHODS TO PRODUCE TYPICAL CARBON FIBER REINFORCED COMPOSITES MULTI-CLAPBOARD FRAME GIRDER

LIU Zhi-jie, YAN Chao, LUO Ji, ZHU Jun-jun

2015, 0(1): 82-87.

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In the paper, a method of resin transfer molded(RTM)was introduced to produce a typical carbon fiber reinforced composites multi-clapboard frame girder. A design of the resin flow route,the fabrication method of the prefab part and some parameters of resin injection were discussed and proposed. Based on a series of experiment results, some conclusions were drawn. At first, the line resin inlet is more compatible to the great complex structures than the point one. Secondly, the raise and appropriate maintenance of injection pressure is in favor of the surface quality of parts. Third, the improvement of vacuum of prefab part and the elimination of air inside the resin is associated with the inner quality of RTM parts. Finally, the filling of extra fibers in the corner of prefab parts will avoid the surface defects caused by the local concentration of resin and its delamination. In the end, the mechanics of RTM parts were measured and discussed.

DISCUSS OF TEST STANDARD IN OBTAINING COMPOSITE MATERIAL STRUCTURE DESIGN PARAMETERS

PAN Bei-chen

2015, 0(1): 88-91.

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For anisotropic composite structure design, it is necessary to get the necessary elastic constants and strength constants to achieve structural design and accurate verification. To obtain the elastic constants and intensity constants, this paper provided test standards, analyzed the characteristics and limitations of each standard,and proposed test standard selection recommendations.

RESEARCH PROGRESS IN EXTRINSIC SELF-HEALING POLYMER COMPOSITES

SHEN Yan-jiao, YANG Tao, NIU Xue-juan, DU Yu

2015, 0(1): 92-96.

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Self-healing polymer composites are important aspects of smart materials. Present research status of self-healing polymer composites was elaborated. Self-healing mechanisms, self-healing system characteristic and present research status of several extrinsic thermosetting polymer self-healing composite materials including microcapsule, hollow fiber, microvessel and thermoplastic self-healing are summarized. At last, development direction and application prospect of self-healing polymer composite materials are prospected.

ADVANCES IN RESISTANCE WELDING OF ADVANCED POLYMER MATRIX COMPOSITES

LIU Hong-bo, Dilmurat ABLIZ, WU Wang-qing, XIE Lei

2015, 0(1): 97-102.

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Due to the superior strength- and stiffness-to-weight ratios and high fatigue resistance, polymer matrix composites are widely used in various industrial fields,fusion bonding technology of polymer matrix composites have been a focus of the research. This paper presents an extensive overview of resistance welding of polymer matrix composites, discusses the process parameters which affect welding process and the temperature distribution. Finally, the paper reviews the realization of resistance welding of thermosetting resin matrix composites and establishment of FEM for resistance welding of polymer matrix composites, and expectations on the future development of resistance welding are put forward.

Industry information contents

2015, 0(1): 103-128.

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