COMPOSITES SCIENCE AND ENGINEERING

ASSESSMENT FOR PLACEMENT SUITABILITY OF PREPREG-PART OF DRAPE

HUANG Wen-zong, SUN Rong-lei, ZHANG Peng, SONG Wen-juan

2013, 0(8): 3-8.

Asbtract ( 97 )

PDF (823KB) ( 110 )

References | Related Articles | Metrics

In the process of automated tape laying (ATL), tack and drape are two characteristics that describe the suitability of prepreg for lay-up. Tack and drape researched individually can help us understand placement suitability of prepreg better. This paper aims at drape of prepreg. Firstly, the meaning of prepreg's drape was discussed and the existing measurement methods and quantitative characterization of prepreg's drape were summarized; Secondly, using“Max. bending force”quantitatively characterizing the drape of prepreg was proposed and viscoelasticity of prepreg and influence of the main processing parameters of ATL, such as lay-up velocity, humidity, hot-air temperature, aging time etc., on prepreg's drape were researched by three point bending test. The experimental results indicate that prepreg's drape increases with the higher temperature and humidity, but decreases with the longer aging time and lower velocity of lay-up; Finally, the engineering significance of drape test was summarized, which provides a reference for the control of the processing parameters on ATL.

NUMERICAL AND EXPERIMENTAL ANALYSIS OF THE NATURAL DYNAMIC CHARACTERISTICS OF COMPOSITE HUB

XU Zhen-yu, SHI Peng, LI Sha

2013, 0(8): 9-11.

Asbtract ( 57 )

PDF (501KB) ( 80 )

References | Related Articles | Metrics

In this paper, based on one composite oar hub, the finite element modal of the hub structure was established with ANSYS. Through the model simulation and calculation, the modal shape and vibration characteristics were obtained, and the model was confirmed by modal experiment. With this analysis, the dynamic characteristics of the hub was known. It provides reference for further kinetic studies and optimization to the composite hub.

NUMERICAL SIMULATION OF PULLING OUT OF SOIL NAIL

MA Chong-wu, LIU Zhong-yu

2013, 0(8): 12-15.

Asbtract ( 44 )

PDF (448KB) ( 86 )

References | Related Articles | Metrics

The hyperbolic model was introduced to describe the relationship between the friction shear stress and the relative shear displacement at the interface between the soil nail and its surrounding soils. Based on the assumpution that the poll-out resistance of the nail follows the Mohr-Coulomb criterion and considering the soil dilatancy effects, the differential equation of dislpacement was derived and its numerical solution was obtained by using the finite difference method. Then the pull-out process was simulated. The results of the proposed model are in good agreement with results of pullout tests, which illustrated that the dilatancy of the soil-nail interface should be taken into account of estimating its pull-out bearing capacity.

RESIDUAL STRENGTHS STUDY OF LAMINATE CONTAINING NOTCH BASED ON 0° LAYER STRESS

TIE Ying, ZHAO Hua-dong, ZHENG Bao-sen

2013, 0(8): 16-20.

Asbtract ( 47 )

PDF (690KB) ( 59 )

References | Related Articles | Metrics

A method to predict the residual strength of composite laminates with notch is presented based on the analytical solved model of the notch-edge stress. Using the 0° layer average stress ratio of the laminate with notch to the one without notch as failure characterization parameter, the residual strengths are studied comparatively. As results are: trend which the failure characterization parameters change with the notch distance and aperture of 90° and 0°layer is calculated, the residual strengths are also obtained, for T300/1034-C laminate plate. Change trends of the failure characterization parameters are compared, for four kinds of common engineering laminate plate. The analytical results are compared with the experimental ones, which certified the validity of the developed method.

CORROSION OF E-GLASS FIBER IN SIMULATED OILFIELD ENVIRONMENTS

MAO Xue-qiang, LI Hou-bu, ZHANG Wen-bo, QI Dong-tao

2013, 0(8): 21-26.

Asbtract ( 72 )

PDF (770KB) ( 70 )

References | Related Articles | Metrics

In order to have a better understanding of corrosion behaviors and mechanisms of E-glass fibers in oilfield environments, two different oilfield atmospheres including CO₂, H₂S and Cl^- were firstly given. After different simulated corrosion tests, morphologies of E-glass fibers were gathered using SEM. Chemical bonding status and elemental analysis were systematically investigated by XPS, IR and EDS. The results reveal that corrosion of E-glass fibers in simulated oilfield acidic media is primarily attributed to ion exchange mechanism, which is not only controlled by acid concentration, but also dominate by formation of complex ions or insoluble salts. The depletion of cations on E-glass fiber surface can disrupt the continuity of glass network, thus disturb the glass structure, therefore reducing the strength of fibers.

THE SURFACE PROPERTIES OF FLUORINATED COPOLYMERS

LI Guo-jun, LI Xin-xin

2013, 0(8): 27-30.

Asbtract ( 42 )

PDF (736KB) ( 86 )

References | Related Articles | Metrics

Wettability is an important property of solid surface and is governed by both the chemical composition and the geometrical micro-structure of the surface. Super-hydrophobic surfaces have attracted significant attention recently for both fundamental research and practical applications. In the paper, the copolymers were synthesized by reversible addition-fragmentation chain transfer (RAFT) in cyclohexanone with monomers methylmethacrylater (MMA), methacrylic acid (MAA) and perfluoroalkyl ethyl methylacrylate (FEMA). The structure of compound was confirmed by FT-IR spectra, ¹H-NMR and MS. The micellization behavior of the block copolymer in toluene solvent was studied. Meanwhile, different hydrophobic surfaces were prepared by solvent evaporation-phase separation process with different solvents such as toluene, tetrahydrofuran, benzotrifluoride and F113. And the contact angle of surfaces generated by toluene was 152.5°, which was significant for the preparation of the cost-effective, lowpollution.

STUDY OF BENDING PROPERTIES OF FILAMENT WINDING PIPE

CAI Hao-peng, WANG Jun-peng, ZHAO Xi-xin, WANG Jun

2013, 0(8): 31-34.

Asbtract ( 47 )

PDF (725KB) ( 135 )

References | Related Articles | Metrics

The influence of filament winding angle on bending properties and failure mode is studied. Results revealed ±45° laminate and pipe present the maximum failure strain. ±45° winded products have the highest deformability when subjected bending load and the radius of curvature is 0.35m after rupture. When winding angle increases, flexibility of FRP pipe decreases drastically. Radius of curvature after rupture is 0.53m when winding angle is 60°, increased by 51% compared to ±45 winding. As the winding angle increases, failure mode turns from buckling to material failure. Increasing winding angle can effectively suppress buckling.

STUDY ON THE PERFORMANCE OF GLASS FABRIC/MEDIUM TEMPERATURE CURING RESIN COMPOSITES

WUYUN Qi-qige, HU Ren-wei

2013, 0(8): 35-38.

Asbtract ( 46 )

PDF (542KB) ( 83 )

References | Related Articles | Metrics

3233B/EW250B prepreg is a type of glass fabric/medium temperature curing resin prepreg which was prepared using hot-melt method in this paper. Then the prepreg was made into composites and its performance was tested. The results show that the processing properties, flame retardancy, dielectric properties and mechanical performance are well-behaved. 3233B resin has good toughness, the roller peeling strength of the sandwich structure is high and the prepreg can curing with the sandwich directly.

THE STUDY AND PREDICTION OF AGING PROPERTIES OF CFRC

YU Qian-qian, HOU Jun-feng, CHEN Gang, WU Zhong-quan

2013, 0(8): 39-43.

Asbtract ( 96 )

PDF (736KB) ( 121 )

References | Related Articles | Metrics

The aging mechanical properties of composites is very important, so accelerated thermo-aging text on carbon fiber composites is performed at 110℃, 120℃, 130℃ and 140℃ temperatures for 300, 600, 900, 1200, 1600 and 2000 hours in this paper. It examines the influence of aging temperature and aging time on tensile strength, compress strength and bending strength of carbon fiber composites, and analyses the influence process. The experiment result indicates that bending property is more sensitive with the change of aging temperature and aging time than tensile property and compress property. At the last, the prediction model of CFRC bending strength is obtained base on the binary regression analysis, and the conspicuousness of model has been tested. The test result shows that the most relative error is only 3.61%, the prediction precision is very good, the model is credible in certain condition.

INTERFACIAL MODIFICATION OF QUARTZ FIBER REINFORCED SILICON-ARYLACETYLENE-CONTAINING RESIN COMPOSITE BY COUPLING AGENT

LIANG Xiu-hua, HU Yan-hong, DU Lei, HUANG Fa-rong

2013, 0(8): 44-50.

Asbtract ( 42 )

PDF (985KB) ( 91 )

References | Related Articles | Metrics

Silicon-arylacetylene-containing resins are organic and inorganic hybrid resins. They were potentially useful as functional materials and exhibited remarkable heat resistant properties and good anti-ablative performances. While, the poor interfacial adhesion with quartz fiber limited the mechanical properties of their composites, due to the resins'weak molecular polarity and low surface energy. A silane coupling agent containing isocyanate was designed and employed in this paper in order to modify the interface of quartz fiber reinforced silicon containing arylacetylene (PSA) composite. The results showed that the interlaminar shear strength (ILSS) of the treated quartz fiber-PSA composite has been greatly improved by 44.7% compared with those untreated. The characterization of the fibers and composites with X-ray photoeletron spectroscopy (XPS), surface energy analysis, atom force microscope (AFM) and scanning electron microscope (SEM) revealed that the coupling agent reacted with the active groups on fiber surface and polar functional groups generated, which increased the quartz fiber's surface energy. As the result, the interfacial adhesion performance between the fibers and the resin improved, the composite's interlaminar shear strength increased.

ONE-STEP SYNTHESIS OF OCTYLENE TERMINATED SILICON NANOPARTICLES BY A SOLUTION ROUTE

ZHAO Qing-peng, DONG Xu, GAO Yun, PAN Zhao-qi

2013, 0(8): 51-54.

Asbtract ( 48 )

PDF (822KB) ( 73 )

References | Related Articles | Metrics

A one-step synthesis, octylene terminated silicon nanoparticles were prepared via co-reduction of silicon tetrachloride and octenyltrichlorosilane using LiAlH4. The particle size and distribution were investigated by transmission electron microscopy. The optical properties were analyzed with UV-visible absorption and fluorescence spectroscopy. Their surface chemistry was characterized using fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. TEM showed that the average diameter of silicon quantum dots was 5.07 ±0.80nm. Optical characterization proved the highly photoluminescence of octylene terminated silicon quantum dots. ¹H NMR and FTIR indicated that octylene group was connected to the surface of silicon nanoparticles with Si-C bond. These results lay the foundation for the further preparation and application of core-shell type silicon nanoparticles and polymer composite fluorescence biological materials.

INFRARED DETECTION TO SANDWICH STRUCTURES WITH INSIDE DEFECTS

YU Yi, LIU Wei-qing, WAN Li, FANG Hai

2013, 0(8): 55-59.

Asbtract ( 38 )

PDF (1137KB) ( 65 )

References | Related Articles | Metrics

The inside detection can course a difference in conduction of the heat wave which leads to a difference of the surface temperature which can be received by thermal imager in the form of images of different colours. The paper makes a research on the defects of sandwich structures including the parametric analysis under transient thermal and steady thermal conditions using finite element software depending on the theories above. By the comparison of the software simulation and the test result, the paper gives the accuracy of infrared detection to sandwich structures with defects. At the same time, some effects which may affect the testing result are analysed and some suggestions about using infrared detection to sandwich defects are made.

EFFECTS OF FABRIC REINFORCEMENT ON THE PROPERTIES OF SANDWICH COMPOSITE PANELS

LIU Yin-yin, JIA Li-xia, LIU Ying

2013, 0(8): 60-64.

Asbtract ( 36 )

PDF (802KB) ( 65 )

References | Related Articles | Metrics

Textile structural composite is a newly developed composite, which is reinforced by textile preforms. There are three different types of sandwich composite panels such as non-fabric reinforced, flat fabric reinforced and spacer fabric reinforced composites. In this paper, the compressive, three points flexural loads, shear and peel properties of each type of sandwich composite panels were tested, and the effects of fabric reinforcement on the properties were investigated. The results indicate that there are synergy effects between pile and foam, the compression performance, shear performance and peel performance of spacer fabric reinforced composite plate are significantly better than the former. The flexural stiffness was no significant difference, but owing to the spacer fabric, the flexural toughness of spacer fabric reinforced composite plate is superior to the former.

Table of Content