Table of Content

28 November 2007, Volume 0 Issue 6

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BASIC STUDY

DISPLACEMENT CALCULATION METHOD OF 0° AND 90° WINDING ANGLE CIRCULAR AND NON-CIRCULAR CROSS-SECTION BEAM UNDER TENSILE AND BENDING LOADINGS

Sun, J., Xiao, Q.

2007, 196(6):  3-5. 

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The work here presents a calculation method for displacements of 0°and 90°winding angle circular and non-circular cross-section beam under tensile and bending loadings.The method involves dividing the beam into finite beam elements,analyzing the elements displacements,strains and stresses of beam elements,transforming the coordinates,integrating displacements and loads of beam elements on the beam and obtaining the displacements of beam under tensile and bending loadings.Comparison between theoretical results and numerical results are done and they have a good agreetment.The results show that the presented method can be used for calculating the displacments of 0°and 90°winding angle circular and non-circular cross-section beam under tensile and bending loadings.

STUDY OF CURING KINETICS OF RESIN SYSTEM FOR COMPOSITE PRESSURE VESSELS

Hu, Z. H., Wang, R. G., Yang, F.

2007, 196(6):  6-8. 

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The resin system for fiber-reinforced composite pressure vessel is studied by non-isothermal DSC.The Malek method is used to deal with the experimental data,and a two-parameter(m,n) autocatalytic model is obtained for describing the curing behavior of the studied resin system.Activation energy is estimated by Ozawa method in autocatalytic model.The predicted temperature in numerical simulation is close to the measured temperature during curing process,which may prove the validity of kinetics model.Therefore,cure kinetic model can present a necessary submodel for simulating transient temperature field of composite pressure vessel.

INVESTIGATION OF EPOXY RESIN FILM FORMULA FOR MODERATE-TEMPERATURE HOT-MELT PREPREG

Cheng, X. Y., Chen, C., Zhang, Z. G., Li, M.

2007, 196(6):  9-13. 

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【Abstract】 According to the film forming property,the resin film's state(in room temperature),DSC curves and the viscosity-temperature characteristics of epoxy matrix,the resin film system which was used as moderate-temperature hot-melt prereg has been designed.The formula involves curing agent/accelerator/epoxy resin with mass porportion of 56/23/100.This system can be cured at mid-temperature.With very exlellent film forming properties,the film was prepared with good toughness at room temperature,which could meet the requirements of moderate-temperature hot-melt prepreg.

PLY STACKING-SEQUENCE OPTIMIZATION OF COMPOSITE LAMINATE PLATES BY ANT COLONY SYSTEM

Mu, P. G., Zhao, M. Y, Chen, P. F., Wan, X. P.

2007, 196(6):  14-17. 

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An ant colony system is applied to solve the optimization problem of ply stacking-sequence of composite laminate plates with given plies.Firstly,the paper transforms the optimization problem of ply stacking-sequence to the traveling salesman problem(TSP) by integer coding and decoding,which was used in genetic algorithm(GA).Secondly,the ant colony system is modified to improve the performance and the efficiency as to meet the engineering requirements.The results of the examples indicate that the method proposed in this paper is effective,efficient and could be easily applied to other engineerings with little modification.

NUMERICAL ANALYSIS OF HOLE-EDGE STRESS DISTRIBUTION OF COMPOSITE MATERIALS PLATE WITH COMPLEX HOLES

Li, C., Tie, Y., Zheng, Y. P.

2007, 196(6):  18-20. 

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The existence of the hole has a great effect on the structural strength.For the hole-edge boundary condition of the complex hole,there are some difficulties in describing it in mathematics.A great error will result from the inadequate accuracy of the establishing of boundary condition during the following calculation.In this paper,accurate boundary conditions of complex hole were presented based on the theory of function of complex variable,with the improvement of ratio of precision of the finite element modeling.The calculation of anisotropic plate with aerofoil manhole under external load was carried out.The numerical solution of hole-edge stress field was obtained.Moreover,the stress distribution of hole-edge and deformation of plate were given.

STUDY OF THE BASIC ANCHOR LENGTH OF FRP BAR BASED ON 1-D NUMERICAL ANALYSIS

Qiao, Y. J., Yang, Q. C.

2007, 196(6):  21-25. 

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The 12 groups data of pullout model tested are simulated based on the 1-D numerical analysis procedure,by which the basic anchor length of FRP bar was obtained.The evolution trend of the distribution of the FRP bar's interface bond strength in the basic anchor length with the increasing of the pullout stress is analyzed.The inclusion shows that the basic anchor length is seriously affected by residual interface strength.The new formula for calculating the FRP bar's basic anchor length is found.The limit bond strength,residual bond strength,diameter and yield strength are considered as the influencing factors in reference to the new formula.The gathered accuracy of the 1-D calculation's results got from the simplified new formula is very well.

MATERIAL RESEARCH

HEAT RESISTANCE OF BORON-DENATURED PHENOLIC FOAM 

Huang, J. Q., Pan, A. J.

2007, 196(6):  26-28. 

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Foamed boron-denatured phenolic resin has been synthesized by adding boron and controlling the pH of the system.The characterization data indicate that this material exhibits excellent heat resistance.Its temperature of heat decomposition is 450℃,mass loss is 60% at 800℃,and the highest service temperature is 200℃.Meanwhile,the influence of the pH of the system on foamability and stability of boron-denatured phenolic resin is studied.The mechanism for the improvement of heat resistance of phenolic foam by boron denaturation is also analysed.

PREPARATION OF POLYPROPYLENE THERMO-PLASTIC COMPOSITES REINFORCED WITH FLAX WEFT KNITTED-FABRIC

Li, H X., Zhou, Y. W., Huang, G.

2007, 196(6):  29-34. 

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 Some flax/polypropylene(PP) thermo-plastic composites that use natural flax fiber as reinforcing material,polypropylene as resin,flat-knitting fabrics with different volume fractions and structures as the pre-pregnant,were studied in the present work.And they were hot-pressed into the friendly-environment technical textile composites.The superior composites structures and processing technology were obtained by analyzing the properties of the flax and polypropylene,designing and analyzing the parameters and processing technology to the knitted pre-pregnant and the composites matrix.The results revealed that the flax/PP knitted pre-pregnant could be processed simply and efficiently,and it could be hot-pressed directly.So the composites with lowercost was developed.In the hot-pressing process,the best pressure was 10MPa with the pre-pregnant of four or six layers and 15MPa with the pre-pregnant of eight layers.

TENSILE PROPERTY STUDY OF UNIDIRECTIONAL KEVLAR/GLASS FIBER HYBRID COMPOSITES

Zhang, M.

2007, 196(6):  35-37. 

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The unidirectional kevlar/glass fiber hybrid composites are made in the present work.The longitudinal tensile strength and stretch modulus have been tested and analyzed.The results showed that most of the fracture of unidirectional hybrid composites are multiple.The more the hybrid interface is,the more possibility the one session fracture is.There is a critical value of Kevlar volume content to the one-hybrid-interface composites,which shows a typical hybrid effect.As to the hybrid composites of more than one interface,if the layer number is certain,the number of interface have a little influence on the tensile strength and stretch modulus of hybrid composites.The tensile strength and stretch modulus of the composites,which the interface number is one,are much higher than that of more than one interface.The tensile properties of pure glass fiber unidirectional composites prepared under different conditions are analyzed.

INFLUENCES OF INITIATOR,INHIBITOR AND ACCELERATOR ON CURING PROPERTY AND STORING TIME FOR DOUGH MOULDING COMPOUND

Yu, L. Z.

2007, 196(6):  38-39. 

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In this paper,influences of initiator,inhibitor and accelevator on curing property and storing time for dough moulding compound are studied.The combination of two initiators such as ertbutyl perbenzoate and ttertbutyl peroctoate,not only improved the production efficiency but also ensured the curing property.In addition,the curing time is shortened,the storing time is ensured and the cost of production is reduced by the addition of hydroquinone or cobalt 2-ethylcaproate.

EQUIPMENT PROCESS

PRELIMINARY DESIGN ON NEW TYPE HYBRID FRP-CONCRETE BRIDGE SUPERSTRUCTURE

Deng, Z. C., Li, J. H.

2007, 196(6):  40-42. 

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The basic design concepts for structures combined with different fiber reinforced plastic materials and concrete are introduced in the present paper.This concept results in cost-effective composite structures with lightweight,high stiffness,excellent corrosion resistance characteristics.What is more,a new type hybrid FRP-concrete bridge superstructure is provided.Meantime,the methods of simplified failure analysis and theoretical formulas for the hybrid FRP-concrete bridge superstructure are presented.In addition,a preliminary design procedure is also provided.

DESIGN OF THE COMPOSITES WINDING SYSTEM FOR GIRDER OF AIRSCREW 

Yang, T, Gao, D. B., Jiang, F., Yang, G. Y., Jin, G. G.

2007, 196(6):  43-45. 

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The shape of girder of airscrew isn't revolving.The winding method of girder of airscrew isn't the same as the revolving body.The winding method and system design is described in the paper.The winding machine and releasing machine is designed.PLC is set as the core of control system of the winding equipment.The winding control section includes continue changing angle speed control unit and releasing composites control unit for constant tension.Temperature control system involves heating up control unit and measuring control unit.Finally,the sample of winded girder of airscrew is offered.

REVIEW

EFFECT OF PHENOLIC RESIN AND REINFORCING FIBER ON ATTRIBUTES OF POLYMER BASED FRICTIONAL MATERIALS 

Meng, C. L., Zhang, L., Zhang, Y.

2007, 196(6):  46-48. 

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Effect of the amount of phenolic resin on friction coefficient and specific wearabilty and reinforcing fiber on impact strength are experimentally studied.And influence of reinforcing fiber on friction and wear is theoretically discussed.The result reveals that the amount of phenolic resin and reinforcing fiber should be reasonably controlled in formula design of polymer-based frictional materials.

STUDY ON PROPERTIES OF GEOPOLYMER MATERIALS

Li, S., Chen, Y. L.

2007, 196(6):  49-52. 

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Geo-polymer is a kind of promising advanced inorganic polymer due to its high degree poly-condensed network structure,excellent thermal and mechanical properties,low energy consumption,low toxic wastes emission and easy recycle,Which make it a kind of green materials.The paper studies the properties and microstructure of the geopolymer materials.The result shows that the flexural strengths of L26,L15 and L21 materials are 26.1MPa and 33.5MPa and 32.8MPa,and compression strengths are 49.3MPa,18.5MPa and 25.8MPa,respectively flexural strength and compression strength of L21 material after sintering at 900℃ for 2 hours reach 20.7MPa and 39.1MPa.

STUDY SITUATION OF THE UNDERWATER SOUND-ABSORBING MATERIALS

Feng, C. M., Guo, W., Xu, W.

2007, 196(6):  53-58. 

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Acoustic sound absorption materials are commonly used in the underwater navigation surfaces.The underwater acoustic stealth design is of great significance in the military applications and gets extensive attention.Polymeric materials like rubber and polyurethane have been extensively applied because of their unique molecular structures.The structural design of sound-absorbing material also has great affection on their performances.In this paper,the main systems and sound absorption material structures were reviewed on the basis of the acoustic absorption mechanisms.