COMPOSITES SCIENCE AND ENGINEERING

CALCULATION OF GFRP CATAMARAN STRUCTURAL STRENGTHUNDER THE MULTIPLE CONDITIONS

LI Yao, LIN Shao-fen, YAN Jin, CHEN Qing-lin

2016, 0(6): 5-10.

Asbtract ( 82 )

PDF (4598KB) ( 199 )

References | Related Articles | Metrics

GFRP catamaran has more dangerous situations than the steel ones under the multiple conditions. It needs to consider its particularity hull strength materials and structures when calculating its structural strength. Now very few research and attention is taken on it. In this paper, by taking the GFRP catamaran as the research object, 10 kinds of major dangerous working conditions are selected as the calculating conditions according to the structures and the actual sail area, using the finite element method to calculate its structural strength under the combined effects of multiple conditions. To change the traditional way of independent analysis towards the dangerous section, the quadratic assignment correction method was presented. The results show that torsion, transverse bending, torsion-transverse combination conditions are the main reason of strength failure. Torsion conditions are the main reason of strength failure. Also, it finds the dangerous conditions and structures which is sensitive to the change of principal stress, and the variation regularity of maximum/minimum principal stress of GFRP panels. Besides, some local structures designed by traditional method are still dangerous. The research methods and conclusions have reference value on the strength calculation of composite yacht.

OPTIMAL DESIGN OF SANDWICH PANELS WITH GFRP FACE SHEETS ANDA FOAM-WEB CORE BASED ON GENETIC ALGORITHM

HE Tao, WANG Lu, LIU Wei-qing, WAN Li

2016, 0(6): 11-15.

Asbtract ( 90 )

PDF (1268KB) ( 159 )

References | Related Articles | Metrics

The composite sandwich panels with GFRP face sheets and a foam-web core (GFFW panels) have been widely used in the structural engineering. However, It is well known that there is lack of the effective optimal design of composite sandwich members. In order to address this issue, an optimal design method was established to decrease the construction cost in this study by the use of genetic algorithms. Finally, compared to the existing GFFW panels, the construction cost of GFFW panel optimized via genetic algorithms exhibits much more economic efficiency.

EFFECT OF CARBON NANO-FIBER TO GLASS FIBER/EPOXY COMPOSITEON MECHANICAL AND WEAR RESISTANCE

DONG Meng-yao, LIU Chun-tai, LV Guang-chao, ZHANG Na

2016, 0(6): 16-20.

Asbtract ( 82 )

PDF (7734KB) ( 74 )

References | Related Articles | Metrics

Vacuum assistant spray method was used to fabricate the glass fiber/epoxy composite with 1% and 3%CNF. Meanwhile, the mechanical properties and solid particle erosion resistance of composites were measured and compared to EP and FRP. The results show that the tensile strength of 1% and 3% CNF composites reached 72 MPa and 70 MPa, compared to EP which were increased by 20% and 16.7%, and compared to FRP which were reduced by 32.7% and 30.7%. The flexural strength reached 150 MPa and 178 MPa, compared to EP which were increased by 40.2% and 66.4%, and compared to FRP which were reduced by 19.8% and 4.8%; the mass loss compared by FRP were reduced by 75% and 86.7%, enhanced the wear resistance of the composite materials.

STUDY OF BIG-VOLUME ARTIFICIAL MARBLE FOR DENSITY/LITHO-DENSITY LOGGING TOOLS

XU Qiang, FENG Dong, LIU Jie, YANG Zhi-gao

2016, 0(6): 21-24.

Asbtract ( 89 )

PDF (772KB) ( 225 )

References | Related Articles | Metrics

A series of big-volume artificial marble with two-calibration-parameters was studied, it was used as photoelectric absorption index (the symbol is P_e) and density calibration standard for petroleum traditional compensated density/litho-density logging tools. It can save half of construction and storing cost, because a set of two-calibration-parameters standard can replace a sets of density standard and a set of photoelectric absorption index standard. The processing technology was obtained based on a series of experimental data, and the compact, fissureless artificial marbles with uniform density were produced, they were synthesized with unsaturated polyester. The density of the artificial marbles was measured with a special balance, and result was accurate to 1 gram.

EXPERIMENTAL STUDY ON FLEXURAL FATIGUE PERFORMANCE OF DAMAGEDREINFORCED CONCRETE BEAMS STRENGTHENED WITH BFRP SHEETS

WANG Hai-liang, GUO Fu

2016, 0(6): 25-32.

Asbtract ( 78 )

PDF (1532KB) ( 245 )

References | Related Articles | Metrics

According to the combined analysis with the actual situation that a large number of deleterious concrete bridges which require strengthening, and the bridge mainly suffer fatigue loading, the fatigue life and stiffness degradation rate of basalt fiber reinforced concrete beams strengthened with different layers of basalt fiber are studiedunder constant and variable amplitudes fatigue loading. Research results demonstrates that: (1)Under constant and variable amplitudes fatigue loading, compared with RC beams strengthened with one layer of BFRP sheets, fatigue lives of RC beams strengthened with two and three layers of BFRP sheets are increased by 20% and 40%, separately. With the same BFRP sheets reinforcement layers, fatigue lives of the strengthened RC beams under variable amplitude fatigue loading are reduced by 16% than those under constant fatigue loading. (2) Variable amplitude fatigue loading can fasten steel bar strains and middle span deflections of beams. The curve of the middle span deflection and fatigue times is obviously "concave" shape. (3) The stiffness degradation rate of beams without BFRP sheets under constant fatigue loading is about 0.313 MN·m²/Million times, while the stiffness degradation rate of beams strengthened with one, two, three layers of BFRP sheets under constant fatigue loading is about 0.014 MN·m²/Million times, and the rate under variable amplitude fatigue loading is about 0.050 MN·m²/Million times. It demonstrates that pasting BFRP sheets reduces stiffness degradation rate of the beams, and variable fatigue loading significantly increased stiffness degradation rate of beams.

PREMILINARY EXPLORATION ON REALIABILITY DESIGN METHOD OFCOMPOSITE STRUCTURE IN WARSHIP

SUN Wei, CHEN Guo-tao, MEI Zhi-yuan, LIU Ling

2016, 0(6): 33-36.

Asbtract ( 103 )

PDF (820KB) ( 210 )

References | Related Articles | Metrics

Reliability is one of the important indexes to measure the inherent reliability of structures. The right selection of reliability analysis and calculation method is the basis and guarantee for the reliability assessment of composite structures in warship. Working environment of composite structures for naval ships is complicated, and the discrete characteristics of its structural mechanics performance is higher than that of the traditional metal structure and the problem of structural reliability is relatively serious because of the limitations of the designing technology and the production capability. For this reason, firstly, the paper analyzes structural strength properties and its regularities of distribution of composite structures for naval vessels. Then,we pesent the method of analyzing reliability of composite structures based on stress-intensity interference model and working out reliability by safety factor method for the design of allowable values of the reference design. In the two parts, it has obvious advantages and operability in solving problems and result accuracy, which has important reference value for the development of structural fatigue reliability assessment of naval vessels.

STUDY ON EVALUATION UNIFORMITY METHOD OF CONTINUOUS FIBER-REINFORCEDCERAMIC COMPOSITES BY ACOUSTIC PARAMETER

LU Ming-hui, DUAN Han-yi

2016, 0(6): 37-43.

Asbtract ( 109 )

PDF (5509KB) ( 189 )

References | Related Articles | Metrics

Continuous fiber-reinforced ceramic composites (CFCC) have excellent properties at high temperature, which is a new type of high temperature components in aerospace field, and has entered the actual use stage in recent years. It is of great significance to study the parameter control in the preparation process, the quality of the product and optimization and the characterization of the material properties. Analysis of production methods and material properties of CFCC shows that this material has coarse grain and high attenuation characteristics. So original ultrasonic method was modified to transmission method to get an accurate understanding of the acoustic characteristics of the material. The measurement of sound velocity, sound attenuation and other parameters was carried out by image. And, the coefficient of variation of "sound" and "amplitude gray-scale map" were selected as two indicators to characterize the uniformity of the material. The results show that velocity uniformity caused by density and acoustic attenuation uniformity caused by pore results are consistent, indicating that the uneven density of the material is caused by pore. Finally, control of the material quality could be realized through the control of the porosity in the material.

THE EFFECTS OF CARBON BLACK ON THE PROPERTY OF PEROXIDECROSSLINKED POLYETHYLENE

YANG Chang-long, ZHENG Wei, BIAN Jian-jian

2016, 0(6): 44-47.

Asbtract ( 107 )

PDF (906KB) ( 172 )

References | Related Articles | Metrics

Peroxide-crosslinked polyethylene (XLPE) was obtained with LDPE as base material, carbon black (CB), dicumyl peroxide (DCP) and antioxidant as assistants. The influences of CB content on XLPE′s properties including mechanics, electricity, thermal stability and weather resistance were studied by tension machine, insulating oil dielectric tester, schering bridge, high resistance meter,thermal aging oven,Xenon weatherometer et al. It was found that,with increasing of concentration of carbon black, mechanical property had no obvious change; weather resistance were improved notably; electric strength and volume resistivity gradually decreased;relative permittivity and dielectric dissipation factor increased obviously. When carbon black content was 1.8%, the insulating property and weather resistance approached optimal balance. And, using compounds of carbon black and certain sulfur-containing antioxidants, the thermal aging property of XLPE was significantly improved.

VIBRATION CHARACTERISTICS OF SINGLE-WALLED CARBON NANOTUBES EMBEDDEDIN NON-LOCAL VISCOELASTIC MEDIUM

LI Qing-li, ZHAO Jing

2016, 0(6): 48-53.

Asbtract ( 80 )

PDF (2437KB) ( 204 )

References | Related Articles | Metrics

Based on the nonlocal elasticity theory, the vibration characteristics of single-walled carbon nanotubes embedded in nonlocal viscoelastic medium are researched. The Euler-Bernoulli beam model and nonlocal viscoelastic foundation model are introduced to establish the governing equations for the vibration of the carbon nanotubes. The transfer function method is then employed to derive the natural frequencies of the embedded carbon nanotubes with arbitrary boundary conditions. Subsequently, a SWCNT embedded in nonlocal viscoelastic medium is taken as a numerical example, and the first three natural frequencies of the SWCNT are obtained for different boundary conditions and nonlocal parameters. In addition, the influences of nonlocal viscoelastic medium on the natural frequencies are examined. The results demonstrate the efficiency of the proposed modeling method for the vibration response of the SWCNTs embedded in a medium.

GEOMETRICAL MODELING OF BRAIDED STRUCTURES WITH POLYGON PRISM

NING Fang-gang, XU Xiao-xia, YU Wei-dong

2016, 0(6): 54-57.

Asbtract ( 111 )

PDF (3471KB) ( 170 )

References | Related Articles | Metrics

This paper introduces a geometric modeling method for braids structure with polygon prism based on the intersection of helical surface and braiding surface. Two kinds of surfaces are abstracted by the decomposition and re-composition of strand motions which include all braiding information. Based on this fact, the modeling method is developed based on the intersection of helical surface and braiding surface and the detailed modeling process is introduced by SolidWorks^ 2013.

STUDY ON SHEAR BEHAVIOR OF PRE-CRACKED SHORT BEAMSSTRENGTHENED WITH BFRP SHEET

ZHAO Lin, YANG Yu-chen, LIU Hua-xin, KONG Xiang-qing

2016, 0(6): 58-63.

Asbtract ( 88 )

PDF (1216KB) ( 171 )

References | Related Articles | Metrics

In order to study the shear performance of short RC beams strengthened with BFRP sheet, 6 RC pre-cracked short beams strengthened with BFRP were studied and analyzed under four-point bending test. The results indicate that the shear capacity of the strengthened beams was 31.6% greater than that of unconfined ones due to the existing of BFRP sheets. At the same time, the mid-span deflection of short beams was reduced. The shear span ratio and strengthening modes affected the shear performance of the tested beams. Strut-and-tie models were used to predict the shear capacity of tested beams and the simplified method fitted well with the test results. Short RC beams strengthened with BFRP sheet is feasible.

THE SAFETY DEGREE OF RC STRUCTURE STRENGTHENEDWITH FIBER REINFORCED POLYMER

WU Yi-bin, XU Li-hua

2016, 0(6): 64-67.

Asbtract ( 92 )

PDF (1012KB) ( 231 )

References | Related Articles | Metrics

In order to further understand the safety degree of RC structure strengthened with fiber reinforced polymer (FRP), the safety degree of the Chinese code (GB50608) and the American guildline (ACI440) are discussed. Based on reviewing on the load and reisitence factor expression and the resistance factors in different reports. It shows that the safety degree of Chinese code is lower than American guildline, the resistance factors can not well express the relationship between the performance of strengthening structure and the safety margin. Thus, some suggestions for furture research are put forward to solve the problems existing in current Chinese code.

RESEARCH ON FIBER PLACEMENT TOOL PRESETTING STRATEGY OFCOMPLEX SIMILAR ROTATION COMPONENT

MA Ding, WANG Xian-feng, XIAO Jun, WEN Li-wei

2016, 0(6): 68-71.

Asbtract ( 104 )

PDF (1163KB) ( 140 )

References | Related Articles | Metrics

In the technical field of composite fiber placement, the tool presetting strategy of similar rotation component is a key factor to judge the manufacturing precision and determine the component manufacturing quality. With the help of laser ranging probe setting at the pressure roller of fiber placement head, every tool presetting point and check point can be monitored. With those probe results, the mold manufacturing precision and adjusting precision can be checked. Based on the mold rotation and probed data, aiming at disposable molds with low cost and reusable molds with high precision respectively, this paper put forward the setting method and tool presetting strategy about mold tool presetting points. And, the experiment of S airplane inlet tape laying is carried out to validate the tool presetting strategy. The tool presetting problem of complex similar rotation component can be solved effectively by using this tool presetting strategy.

STUDY ON THE WARPAGE CAUSED BY SHARP CORNER EFFECT IN GLASS FIBERREINFORCED PA66 INJECTION-MOLDED PART

JIAN Fa-ping, WAN Jun, DU Ji-tao

2016, 0(6): 72-75.

Asbtract ( 160 )

PDF (4751KB) ( 236 )

References | Related Articles | Metrics

Through analyzing an electrical molding part produced with glass fiber reinforced PA66 by Moldflow, the reason of warpage deformation caused by sharp corner effect was found. Then the best gate location was obtained under different gate number by CAE. The result showed that the warpage caused by the sharp corner effect significantly decreased by 56.216% by three-gating injection mold, and better fiber orientation was obtained on the sharp corner.

A COMPARATIVE ANALYSIS OF TWO DIFFERENT KINDS OF ALUMINUM LINERCARBON FILAMENT-WOUND COMPOSITE GAS CYLINDERS

ZHOU Dan, WANG Ying-jun, SUN Ming-qing

2016, 0(6): 76-80.

Asbtract ( 141 )

PDF (1624KB) ( 277 )

References | Related Articles | Metrics

Based on the grid theory and the theory of composite laminated plate elastic-plastic analysis, and with the reference standards of the DOT CFFC "Basic requirements for fully wrapped carbon-fiber reinforced aluminum lined cylinders", a 70 L carbon-fiber wrapped composite cylinder lined with aluminum was designed. Then, an analysis between two cylinders lined with aluminum alloy 6061 and aluminum alloy 7075 respectively is conducted under the same auto-frottage pressure and work pressure. The results show that the distribution of liner stress is more uniform using aluminum alloy 6061 as liner, and the advantage of high strength of the outer carbon-fiber can be better brought out. Additionally, aluminum alloy 6061 is more economical. So, compared with aluminum alloy 7075, the aluminum alloy 6061 is much more suitable to be a composite material for the cylinder liner material.

THE DYNAMIC STRAIN INFLUENCED BY TEMPERATURE IN FATIGUE TEST BLADE

LIANG Ying

2016, 0(6): 81-83.

Asbtract ( 79 )

PDF (876KB) ( 191 )

References | Related Articles | Metrics

In the environment with different temperature, the modulus of unidirectional fabric composites in wind turbine blade is influenced by temperature at large extent, resulting in the change of the blade nature frequency, finally leading to dynamic strain changing in the fatigue test blade. And the fatigue test load is monitored by the dynamic strain. This paper introduced how temperatures influence fatigue test blade, and summarized how to adjust the frequency change to get relative dynamic strain in the critical area to ensure the accuracy of the applied fatigue test load.

THE DEVELOPMENT AND RESEARCH OF FLUID-STRUCTUREINTERACTION FOR COMPOSITE PROPELLER

ZHANG Xu-ting, HONG Yi, YUAN Feng, JIAO Wei-cheng

2016, 0(6): 84-87.

Asbtract ( 154 )

PDF (918KB) ( 214 )

References | Related Articles | Metrics

The method of fluid-structure interaction is one of the important tools in the composite propeller performance study because composite propeller has a larger deformation than metal propeller that makes the previous simple fluid or structure research methods unavailable. Hydrodynamic performance and structural response of composite propeller can be obtained by solving the equations of fluid-structure interaction. However, the fluid-structure interaction equations are implicit which is very difficult to be solved directly. The most effective way to solve the equations is the numerical solution methods. In this paper, the main stream fluid-structure interaction numerical analysis method(VLM/FEM, BEM/FEM, CFD/FEM)was introduced by reviewing and summarizing the composite propeller fluid-structure interaction papers from both domestic and foreign. In order to provide reference for further investigate, the paper briefly describes the research and development status of composite propeller fluid-structure interaction and points out the development trend for the future.

APPLICATIONS OF FURAN/MALEIMIDE DIELS-ALDER REACTIONSTO SELF-HEALING POLYMER COMPOSITES

ZHAO Qing-song, JIANG Sheng-ling, ZHANG Xiao-a, YUAN Rong-ping

2016, 0(6): 88-93.

Asbtract ( 169 )

PDF (4470KB) ( 226 )

References | Related Articles | Metrics

Diels-Alder reactions (DA reactions) using furans as a diene and maleimides as a dienophile are one of the most important DA reactions being used in self-healing polymer composites. Six types of DA polymerization and copolymerization from furan derivatives and maleimide derivatives including linear, branched and crosslinked reactions as well as the DA reactions of polymers containing both furan derivatives and maleimide derivatives in main chain or side chain were summarized. The progress in the applications of furans/maleimides DA reactions to self-healing both bulk and interphase of polymer composites including microcapsules, hollow glass fibers and microvascular network techniques and interfaces of polymer/fiber, polymer/silica, polymer/layered silicates and polymer/grapheme were reviewed.

Table of Content