Table of Content

28 October 2015, Volume 0 Issue 10

Previous Issue    Next Issue

BASIC STUDY

RESEARCH IN CURING KINETICS OF THE COMPLEX INITIATION SYSTEM USING IN SYNTHETIC QUARTZ OF UNSATURATED POLYESTER RESIN

WU Xia, WANG Ji-hui, NI Ai-qing

2015, 0(10):  5-9. 

Asbtract ( 42 )   PDF (1720KB) ( 89 )  

References | Related Articles | Metrics

The mechanical properties of synthetic quartz of unsaturated polyester resin are compared for different recipes of the complex initiation system. The initiation system consists of benzoyl peroxide (BPO) and tert-butyl peroxy-2-ethylhexanoate (OT). The non-isothermal curing kinetics of the unsaturated polyester resin with complex initiation system was studied using differential scanning calorimetry (DSC). Kissinger and Crane equations are used to obtain the curing kinetics model of unsaturated polyester based on the experimental data obtained. Then, the model developed was verified and modified and better agreement with experiments was achieved.

PREPARATION AND CHARACTERIZATION OF POLYIMIDE/TiO₂ COMPOSITE FILM

YANG Zhi-lan

2015, 0(10):  10-13. 

Asbtract ( 44 )   PDF (2488KB) ( 56 )  

References | Related Articles | Metrics

Polyimide/TiO₂ composite films were prepared via sol-gel reaction using tetrabutyl titanate (TBT) as the inorganic precursor and incorporating it into poly (amic acid) (PAA) derived from 3,3',4,4'-biphenyl tetracarboxylic diandhydride (BPDA)and 4,4'-diaminodiphenyl ether (ODA) in N,N-dimethylacetamide (DMAc). The chemical structure and compatibility of the hybrid film were characterized by FFIR and SEM, respectively. The effect of TiO₂ content on mechanical property and thermal behavior of hybrid film was studied. The results indicated that the nano TiO₂ particles dispersed uniformly in polyimide matrix. And the comprehensive properties were optimal when the content of TiO₂ is about 2wt.%.

OPTIMAL SENSOR PLACEMENT FOR WIND TURBINE BLADE BASED ON MULTIPLE STRATEGIES

ZHAO Yu, GU Gui-mei

2015, 0(10):  14-18. 

Asbtract ( 47 )   PDF (1345KB) ( 77 )  

References | Related Articles | Metrics

In order to collect date by sensors effectively and improve the accuracy of wind turbine blade's monitoring system, a new sensor placement method based on the multiple optimization strategies was presented. Firstly, to improve the convergence rate, QR-factorization method was used to screen the initial test point group. Secondly, the modal assurance criterion (MAC) matrix was taken as the target function, and a method of determining sensors number was proposed by the maximum off-diagonal element of MAC. Finally, in order to solve the problem that the traditional genetic algorithm is easy to fall into, local optimal solution and slow convergence SA was used as an operator of the genetic algorithm. The two kinds of mature intelligent algorithm was combined under the framework of Memetic by complementary advantage. The plan of optimal sensor placement for a 2-MW wind turbine blade was performed and compared with the traditional QR method and the standard genetic algorithm. The final results indicate that the arrangement through the new optimal method could solve the optimal sensor placement of blade and have better performance in convergence and optimization effect than the QR method and genetic algorithm.

RESEARCH ON WINDING PATTERNS FOR FILAMENT WOUND COMPOSITE ELBOWS

LI Yan-hu, ZU Lei, GAO Feng, ZHANG Gui-ming

2015, 0(10):  19-25. 

Asbtract ( 40 )   PDF (3887KB) ( 72 )  

References | Related Articles | Metrics

The mathematical model of filament-wound composite elbows is presented based on geodesic trajectories. The cylindrical sections are used for transiting the torus part in the middle and the both end parts. The torus part is overwound using geodesics, and the both cylindrical parts are produced using non-geodesics to ensure a smooth transition of fiber trajectories at the both ends. The stability-ensuring conditions of composite elbows are derived with the aid of differential geometry. The equations for determining the winding patterns and the minimum-required winding angles are formulated. The influence of various relative bending radii and tube radii on the resulting winding angles is evaluated. The obtained winding patterns are simulated and validated using MATLAB codes. The results show that the winding patterns obtained using the present method satisfy the windability of the elbow and meet the basic requirements for filament winding technology.

STUDY OF THE INFLUENCE OF WINDING TENSION TO THE THIN WALL METAL LINING COMPOSITE GAS CYLINDER

LIN Song, WANG Jun-feng, MU Han, LIU Sheng-li

2015, 0(10):  26-30. 

Asbtract ( 69 )   PDF (3043KB) ( 62 )  

References | Related Articles | Metrics

In order to study the influence of winding tension to the mechanical properties of metal inner lining composite gas cylinder, the NOL ring samples and composite gas cylinders were fabricated by different winding tensions. The fatigue and abruption tests were carried out, which were followed by acoustic emission test. Moreover, the external pressure of the thin wall metal inner lining was also tested. The results indicated that external pressure of the thin wall metal lining (1.4mm) was low. Winding tension presented great impact on the fatigue properties and blowing up pressure of the composite gas cylinders. Water pressure experiments and acoustic emission test could be used to frame the best winding tension of the gas cylinders.

STUDY ON THE PROPERTIES OF SOLVENT-FREE MWNTs NANOFLUIDS/PP NANOCOMPOSITES

ZHANG Jun, ZHENG Ya-ping, YANG Rui-lu,QIN Ming

2015, 0(10):  31-35. 

Asbtract ( 66 )   PDF (5503KB) ( 69 )  

References | Related Articles | Metrics

Ionic solvent-free multi-walled carbon nanotubes (MWNTs) nanofluids were obtained with the MWNTs as core, N,N-didecyl-N-methyl-N-(3-trimethoxysilylpropyl)ammonium chloride as corona and poly(ethylene glycol)4-nonylphenyl3-sulfopropyl ether potassium salt as canopy. And N,N-didecyl-N-methyl-N-(3-trimethoxysilylpropyl) ammonium chloride by ion exchange reaction. The structure and properties of nanofluids were studied by TEM, DSC, TGA and rheological testing. Solvent-free MWNTs nanofluids/PP nanocomposites were prepared through solution blending and mechanical blending. The effect of solvent-free MWNTs nanofluids on crystallinity of PP was studied. As a result, the MWNTs content is 23.67wt%. The solvent-free nanofluids have liquid-like behaviour. The solvent-free MWNTs nanofluids can improve the formation and number of crystal nucleus. The degree of crystallinity of the polypropylene matrix was improved a lot.

STUDY ON THE REPRESENTATION METHOD OF DISPERSION DEGREE IN THE C/G HYBRID COMPOSITE LAMINATED BOARD

MA Teng, LI Wei

2015, 0(10):  36-41. 

Asbtract ( 42 )   PDF (2448KB) ( 73 )  

References | Related Articles | Metrics

In this paper, the C/G hybrid composite laminated boards are classified. The quantitative and qualitative representation methods of interlayer mixing dispersion are summarized and analyzed. A method that applies to the characterization of both interlayer composite and unidirectional inner ply composite is presented. The shortage of only using hybrid ratio to describe the relationship between the enhanced components and mechanical property of hybrid composite is solved. And it can be applied to the characterization of both interlayer composite and unidirectional inner ply composite.

PREPARATION AND PROPERTIES OF A GF/EPOXY-NOMEX HONEYCOMB CORED SANDWICH COMPOSITE

WANG Wei, ZUO Xiao-biao, FENG Zhi-hai, YAN Xue

2015, 0(10):  42-47. 

Asbtract ( 47 )   PDF (1613KB) ( 59 )  

References | Related Articles | Metrics

Glass fiber reinforced epoxy prepreg, flame retardant adhesive film and high density Nomex honeycomb core were used to manufacture sandwich composites by co-curing process in autoclave. The rheological properties of epoxy resins from prepreg face and adhesive film, the influences of applied pressure and heating during co-curing process on the mechanical properties of as-prepared sandwich panels, were investigated to determine a moderate processing profile. Combined with the above results, the properties of sandwich panels manufactured by using different areal density adhesive films and ply structures were further measured. It is found that by increasing the areal density of adhesive film, climbing drum peel strength and long beam bending properties both improve obviously and there is no significant effect on flatwise compressive strength. However, the flame retardant properties, smoke density and toxic gas release properties all decrease. The experiment results also show that the Nomex honeycomb cored sandwich panels with symmetric ply structure have more mechanical stability than unsymmetric ply structures.

EFFECTS OF ADDING GLASS-FIBER SURFACE MAT TO THE IMPROVEMENT OF FRP INTER-LAMINAR TOUGHNESS

WEI Hao, ZHU Ling, WANG Ji-hui

2015, 0(10):  48-52. 

Asbtract ( 46 )   PDF (3431KB) ( 71 )  

References | Related Articles | Metrics

Improving the impact toughness and energy absorption abilities of the composite is very important. In this paper, the improvement of inter-laminar toughness through adding glass-fiber surface mat was investigated. S-4800 field emission scanning electron microscope (FESEM), optical microscopy, compression-shearing, 3-piont bending as well as tensile tests were carried out on the specimens of fiber-glass/resin laminates with and without fiber-glass surface mat, respectively. Fracture morphology showed that specimens with surface mat fractured in the surface mat laminar and short fibers worked as bridges which connect the adjacent layers and the fracture surface were relatively rough. The fiber bridging affected the failure mechanism and increased energy absorption ability. It was observed that the energy absorption of specimens with the surface mat increased by 7.3%. Mechanical tests indicated that the force-displacement slope of specimens with the surface mat became more smoothly and the fracture displacement was bigger as compared to the specimens without the surface mat. The results revealed that adding the surface mat reduced the shear stress and the shear modulus by 15.7% and 24.5%, respectively. Besides, adding the surface mat may decrease the curvature of fiber yarns, which will increase the resistance to fail.

APPLICATION RESEARCH

EXPERIMENTAL STUDY ON FLEXURAL BEHAVIOR OF PAULOWNIA WOODEN CORE SANDWICH COMPOSITE BEAM REINFORCED WITH LATTICE WEB

WU Zhong-yuan, FANG Hai, LIU Wei-qing, ZHU Lu

2015, 0(10):  53-57. 

Asbtract ( 47 )   PDF (1686KB) ( 65 )  

References | Related Articles | Metrics

Composite and its sandwich structures are featured in high strength, corrosion resistance, energy-saving, insulation and heat preservation, etc. The paper tries to forge a lattice plate interface plus paulownia wood core composite beam by taking glass fiber reinforced composite as the surface layer and the lattice plate, by using paulownia wood as the core material and by adopting the molding process of vacuum infusion. It makes an experimental comparative study between the four-point (on planes and flanks) flexural property of wood beam and that of the non-lattice wood core beam and lattice wood core beam under the condition that total sizes of the test items remain unchanged. The paper has come out with the conclusion that: when a same test item is under pressure, the ultimate bearing capacity and rigidity of the plane are higher than those of the flank; the ultimate bearing capacity and rigidity of non-lattice wood core beam and lattice wood core beam test items are higher than those of wood beam test items; the ultimate bearing capacity and rigidity of lattice wood core beam test items are higher than those of non-lattice wood core beam test items.

EXPERIMENTAL INVESTIGATION OF THE RESISTANCE WELDING FOR THERMOSETTING-MATRIX COMPOSITES

LIU Hong-bo, XIE Lei, DUAN Yu-gang, LI Di-chen

2015, 0(10):  58-63. 

Asbtract ( 82 )   PDF (4090KB) ( 135 )  

References | Related Articles | Metrics

A experimental investigation of the resistance welding of carbon fibre reinforced epoxy laminate is presented. The bonding surface of the laminate is coated with a layer of binder as welding medium and the interpenetration polymer network was created between epoxy and binder during curing process. The temperature distribution of the welding interface was measured and compared to those simulated by finite element model, the statistical distribution of the resistance of the unidirection and fabric heating elements was characterized, and the effects of the temperature on the heating element resistance were evaluated. Maximum lap shear strengths of 7.35MPa was obtained using unidirectional heating element for the AX8900 bindered epoxy/CF laminate. Three failure mechanisms, leading to different values of lap shear strength, were identified including tearing of heating element, cohesive failure of the binders and interfacial failure. A comparison between unidirectional, fabric and mental mesh heating element, in terms of lap shear strength was performed. The results show that fabric and mental mesh heating element can significantly improve the lap shear strength. A processing window based on the parameters, i.e. power level and welding time, was crated.

RESEARCH ON THICKNESS CONTROL METHODS FOR HIGH-PERFORMANCE THERMOPLASTIC PLATE

XU Guang-lei, HU Zhao-hui, ZHANG Bo-ming, ZHENG Yong-zhe

2015, 0(10):  64-67. 

Asbtract ( 54 )   PDF (950KB) ( 85 )  

References | Related Articles | Metrics

As a kind of out-of-autoclave process, moulding process which has advantages of low energy consumption, short process cycle, fine process window and high dimensional accuracy,is the development trend of low-cost process for high-performance thermoplastic composite. Mould design, prepreg laying and process window optimizion are studied in order to obtain thickness control methods for thermoplastic plate. Considering above factors, CF/PPS plate is manufactured and thickness of the plate are tested by special measuring tool. It is shown that dimensional accuracy of CF/PPS plate is fine and thickness uniformity is controlled within ±5.7%. This result will provide technical support for design and manufacturing of thermoplastic plate, and lay the foundation for moulding process application on high-performance thermoplastic product.

PREPARATION OF GLASS FIBER REINFORCED COMPOSITE TAPE

WANG Da-peng, WANG Qing-zhao, CHENG Quan-biao, XIE Zhi-wei

2015, 0(10):  68-71. 

Asbtract ( 56 )   PDF (862KB) ( 67 )  

References | Related Articles | Metrics

The glass fiber reinforced composite tape can be prepared by first treating the glass fiber by coupling reagent and removing water through heating box, then compositing it with HDPE in the mold and finally making it to be a tape under pressure. This article describes how the glass fiber reinforced composite tapes were prepared under different processing conditions. The purpose of testing the mechanical performance of the tape was to find out the optimal process condition. The results showed that the optimal heating temperature was 170℃ and the optimal speed of fiber passing through the heating box was 6m/min.The optimal pressure for the tape formation was 500N and the optimal tension force was 7N.

STUDY ON MOULD DESIGN TECHNOLOGY OF COMPOSITE COMPLEX MULTI-RIB SHELL

LIU Gui, CHAI Peng-jun, LIU Hai-xin, ZHAO Zhi-ying

2015, 0(10):  72-74. 

Asbtract ( 43 )   PDF (1610KB) ( 62 )  

References | Related Articles | Metrics

According to the structure features of composite complex multi-rib shell, and the forming features of the VARTM plan,a new easily broken mould was presented. The easily broken mould was designed and manufactured on the basis of conventional mould. By suing the vacuum assisted forming process, the prototype of the shell was successfully manufactured, and it had met the requirements of the product design. It provides a new way for the mould design technology of composite structure shell with staggered reinforcement ribs.

DEVELOPMENT AND TESTING OF GLASS FIBER REINFORCED PLASTICS ANCHOR RING MADE THROUGH WET WINDING

LIU Jian-yue, CUI Xiao-chao, LIU Wei-jing, ZHAGN Zhu

2015, 0(10):  75-77. 

Asbtract ( 70 )   PDF (1296KB) ( 77 )  

References | Related Articles | Metrics

For a long period, anchor ring in supporting system used metal as its producing material. Coal road has a moist and corrosive situation, which may cause the pyramidal faces of anchor ring and clips to rust and even lose work. When rock faces has the tendency of motion, the clips and anchor ring will not bite well due to the increase of friction coefficient in contact area. The corrosion problem has been influencing the safety problem and durability of permanent anchor supporting system. Glass Fiber Reinforced Plastics (GFRP) is a kind of material which composited by high-strength and low-density glass fiber material and hardener. GFRP has the properties of high strength of extension and low shear strength. For acid and alkali resistance and its outstanding mechanics properties, it has been used increasingly in anchor supporting system. In this paper, we designed a glass fiber reinforced plastics anchor ring in supporting structure of mining anchor and its production process of wet winding forming. After the period of production, loading test and tensile test were conducted on the produced anchor ring. The pressure-bearing capacity of GFRP anchor ring is more than 500kN and the ultimate tensile strength is 464kN. According to the results, unsaturated polyester resin anchor ring which is made of alkali-free glass fiber and made through filament winding has the advantages of light quality, easily forming, acid and alkali resistance, etc.

THE DEGRADATION OF EPOXY COMPOSITE WITH PRESSURE METHOD AND THE RECOVERY AND UTILIZATION OF CARBON FIBER

ZOU Zhen-yue, QIN Yan, XU Ya-feng, CHEN Lin-kai

2015, 0(10):  78-82. 

Asbtract ( 39 )   PDF (3834KB) ( 71 )  

References | Related Articles | Metrics

This article studies the composites degradation process by the one-step pressure method consisting of solvent method, tests composition and characteristic of the degradation product and explores the possibility of using recovery carbon fiber. By using the infrared analysis to determine the bond breaking mainly in the form of cleavage of ether bond. Analysis of degradation products were identified, which is mainly associated with propane and 2-ketone by GC-MS. The SEM micro-structure and fracture morphology of material fracture show that the resin adhere to carbon fiber is almost removed and there is a good interface bonding between the fiber and resin. Fiber mechanical properties testing identified recovery carbon fiber also has good mechanical property. The test of mechanical properties of composite materials indicates that the performance loss is little. Research shows that: the method has high degradation efficiency and monofilament tensile strength of recovery fiber retention rate is high, and the recovery fiber has a very good application prospect.

REVIEW

RESEARCH PROGRESS IN THERMOFORMABILITY OF CONTINUOUS FIBER REINFORCED THERMOPLASTIC COMPOSITES

XU Zi-hang, LIU Dong, QIAN Qun, ZHU Ying-dan

2015, 0(10):  83-86. 

Asbtract ( 46 )   PDF (1260KB) ( 95 )  

References | Related Articles | Metrics

Continuous fiber reinforced thermoplastic (CFRTP) is one of the hot topics in international composites. In this paper, the thermoforming theory is briefly reviewed. And previous studies on experimental methods and simulation models of CFRTP thermoforming are compared in detail. Also, the influencing factors on the thermoforming of CFRTP are analyzed and the research directions of thermoforming of CFRTP in future are pointed out.

THE APPLICATION OF FRP USED IN WET ELECTROSTATIC PRECIPITATOR (WESP)

LI Na

2015, 0(10):  87-90. 

Asbtract ( 44 )   PDF (1077KB) ( 118 )  

References | Related Articles | Metrics

This article introduces the operational principle and the structure of WESP facility, analyses the cha-racteristic and process of FRP,and explains the useful of FRP in WSEP facility.