- Volume 45,Issue 2,2015 Table of Contents
>综述
-
2015, 45(2).
Abstract:
Different from traditional welded aluminum鄄alloy tank, the design emphasis of composite tank is fo鄄cused on preventing leakage of propellant effectively, such as liquid hydrogen and oxygen, which based on the mecha鄄nism of micro鄄crack initiation and propagation in resin during the full service periods. Based on the structural featuresof aerospace composite tank, this paper summarized the resin matrix composite performance at low temperature, de鄄sign criteria of composite tank and primary structure design of tank. Finally, the application prospects of compositetank are also proposed. -
2015, 45(2).
Abstract:
In this paper, the synthesis and properties of various aryl trifiuorovinyl ether (TFV) monomers andtheir perfiuorocyclobutyl(PFCB) aryl ether polymers is discussed. Also, the potential applications include pho-tonics,polymer light emitting diodes (PLEDs), membranes, atomic oxygen (AO) resistant materials etc. were reviewed. >计算材料学
-
2015, 45(2).
Abstract:
In this paper an equivalent method based on sandwich plate theory is deduced and the equivalent pa鄄rameters of the honeycomb plate are obtained. With these equivalent parameters, the honeycomb plate FEM simula鄄tion model is established and honeycomb sandwich plate static analysis and random vibration analysis are completed.Then static and random vibration tests were made. The results indicated that the honeycomb sandwich plate theorybased model can accurately reflect the honeycomb sandwich plate static strength characteristics and structural dynamiccharacteristics. Static strain value and the error is less than 4%, the natural vibration frequency and the error is lessthan 5%, which shows good agreement with tests results and the effectiveness of the model. -
2015, 45(2).
Abstract:
A new structural model was built to study tensile properties of three鄄dimensional hollow sandwichcomposites (3D composites) by using the finite element software Workbench. The distribution of stress & strain on thefibers, resin and the 3D composites was discussed under tensile loads of 1 mm displacement by using the model. Theresults show that the maximum value of stress occured between the overlap of X鄄shaped piles, where the 3D compos鄄ites damaged easily. The minimum value of stress occured on the up and down face鄄sheet, where the 3D compositesdamaged difficulty. The main loads were supported by reinforced fibers and the minor loads were supported by matrixresin. The main failure mode of the 3D composites are resin fracture when the 3D composites suffered tensile displace鄄ment loads at 1 mm. -
2015, 45(2).
Abstract:
In order to meet the demand that working temperature of the composite layer should be below 80益,an insulation layer is wrapped around the composite overwrapped pressure vessel (COPV) mounted in the engine com鄄partment of launch vehicles. Based on lumped parameter method, structural parameters and physical property data ofa 40 L COPV, a numerical model in consideration of the radiation, conduction and convection process was estab鄄lished. It analyzed the insulation performance and discussed the influence of the insulation layer thickness. Moreover,insulation tests of the COPV wrapped by an insulation layer with the thickness of 5 mm or 10 mm were carried out.The numerical results agree well with the experiment measurements. >新材料新工艺
-
2015, 45(2).
Abstract:
Based on 18 Al-Li alloys with various Cu (3. 24% ~ 4. 16%) and Li (0. 94% ~ 1. 44%) con鄄tents, the influence of Cu and Li contents on the mechanical properties and microstructures of T8 aged Al-Li alloyswith micro鄄alloying elements of 0. 4Mg, 0. 4Ag and 0. 4Zn was investigated. The strengthening effect and microstruc鄄ture variation were analyzed through total non鄄solution atomic fraction of Cu and Li and their atomic ratio. Thestrengthening precipitates consisted of T1(Al2CuLi), q忆(Al2Cu) and d忆(Al3Li). With increasing the total non鄄solu鄄tion atomic fraction of Cu and Li and their atomic ratio, the total amounts of precipitates and the proportion of T1 pre鄄cipitates were increased, the alloy strength was enhanced. Lower Cu/ Li atomic ratio led to an increase in d忆precipi鄄tates, and therefore lowered the alloy strength. -
2015, 45(2).
Abstract:
The interfacial properties and pressure vessel performance of PBO fiber and T700 carbon fiber hybridcomposites were studied in this paper. The effects of hybrid ratio on interfacial adhesion properties and water absorp鄄tion of hybrid composites were investigated by interlaminar shear strength (ILSS) and water absorption measurements.Standard 囟150 mm pressure vessels were prepared by PBO fiber and T700 carbon fiber hybrid composites. The waterexplosion and axial bearing tests of 椎150 mm pressure vessels were conducted. The results indicate that the ILSS ofhybrid composites went up with hybrid ratio increasing, the interfacial adhesion properties of hybrid composites sawlittle improvement as T700 carbon fiber content was lower. The water absorption values of hybrid composites were be鄄tween PBO and T700 fiber reinforced composites, which matches the mixture law nearly, and the number of interfacehad remarkable effect on water absorption of hybrid composites. The PV/ W of 囟150 mm pressure vessels prepared byhybrid composites decreased as hybrid ratio increasing. The axial bearing property of PBO fiber reinforced compositeswas improved by 31% with hybrid technology. -
2015, 45(2).
Abstract:
The dispersion of carbon nanotubes in epoxy resin fabricated in different technological conditions wasmacroscopical characterized by stewing oberservation, viscosity and fineness respectively. The results reveal that asthe dispersion of carbon nanotubes is good, the viscosity of epoxy is big, the fineness is low, and the conserving timeis long. There are three means could all characterize the dispersion uniformity of carbon nanotubes, viscosity and fine鄄ness could characterize the dispersion of carbon nanotubes quickly, but the specific evaluation criterion should befound before. In this paper, the dispersions of carbon nanotubes were characterized quickly by establishing the corre鄄sponding relation of scraper fineness and the dispersion. This method is quick, direct, accurate and easily operated,compared to conventional micro-characterization technique. -
2015, 45(2).
Abstract:
T800/5228A composite is toughned Interlaminately with PAEK, and FESEM. GIC and GIIC is testedand analysized comparatively. FESEM show that PAEK/5228A bi鄄continue microstructure form in T800/5228E inter鄄laminate, of which composite is named for the PAEK toughned T800/5228A. Data of GIC and GIIC increase 68. 01%and 30. 97% respectively, due to “hammer effect冶. Crack in “z direction冶and “plastic distortion冶probably in subse鄄quent FESEM research, and deformation interspace is restricted for GIC characterization responsible for the low鄄gradetoughness improvment comparative to GIIC characterization. -
2015, 45(2).
Abstract:
A polysilazane PHSZ with high molecular weight was prepared via the polymerization of cyclic si鄄lazane MHSZ in the presence of tetrabutylammonium fluoride as catalyst. MHSZ was synthesized by the ammonolysisof methylhydrodichlorosilane. Combined with apparatus of IR, NMR, GPC and TGA, the effect of polymerization timeon the composition, structure, molecular weight and ceramic yield of PHSZ was studied. The structure and composi鄄tion of the pyrolyzed products in the atmosphere of ammonia combined with nitrogen were investigated. It is suggestedthat the molecular weight of the polymer PHSZ improved with the extension of the reaction time and TGA decreased;PHSZ converts into Si3N4 ceramic matrix composites with a carbon content of 0. 5wt%, the product of pyrolysis at 1600益is completely crystallized, the crystal phase is mainly 琢-Si3N4. -
2015, 45(2).
Abstract:
This paper focus on studying the effects of two different curing agents (tetrahydromeythyl-1,3-iso鄄benzofurandione MeTHPA, and 4,4-diaminodiphenyl sulfone DDS) on curing reaction and curing properties of 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane tetraglycidyl ether(TGE). The curing behavior of the TGE was characterized byscanning calorimetry analysis (DSC). The results demonstrated that curing reaction activating energy of two epoxy res鄄in/ hardener systems were 65.8 kJ/ mol and 68.4 kJ/ mol, respectively. The curing resin thermal properties and mechan鄄ical properties were investigated by dynamic mechanical analysis (DMA), thermal gravity analysis (TGA) and universaltesting machine, respecticaly. The glass transition temperature(Tg) of MeTHPA system is 188益. Tensile and flexuralstrength is 33 MPa and 48 MPa. The Tg of DDS system is 203益. Tensile and flexural strength is 61 MPa and 93 MPa. -
2015, 45(2).
Abstract:
In this paper, two processes for preparing needled felt with non鄄woven cloth reinforced C/ C compos鄄ites are compared. Needled preforms are treated firstly with a CVI pre鄄densified process, and then the preforms aredensified by pitch impregnation/ carbonization. The results show that the tensile strength in axial direction is increasedby 234%, the interlaminar shear strength is increased by 126%. In addition , the thermal diffusivity is obviously in鄄creased, while the axial coefficient of thermal expansion( CTE) is decreased. It is concluded that the material hasgood comprehensive properties. -
2015, 45(2).
Abstract:
Glass fibers were used as raw material, and the special 3D weaving process was used to weave the new3D sandwich fabric whose warp cross section was a rectangle. The resin matrix was consisted of epoxy resin E-51 and cu鄄ring agent 9055. The 3D sandwich fabric was made into 3D fabric sandwich composite through the hand lay鄄up process. Themechanical properties of 3D fabric sandwich composites with core height of 10 mm, 20 mm and 30 mm were studied. Andthe effect of core height on the compression properties and flexure properties of the composites were mainly analyzed. Theresults show that the compressive strength and compressive elasticity modulus of the composites decrease with the increaseof core height. The flexural strength of the composites increase with the increase of core height, while the flexural elasticitymodulus decrease. And the flexural strength in weft direction is better than that in warp one. -
2015, 45(2).
Abstract:
The F-8H3/602 aramid fiber reinforced composites laminates with different content of epoxy resinwere prepared. The effect of resin content on impact toughness, interlaminar shear strength and flexural propertieswere studied. The morphologies of damaged samples were observed by microscope and scanning electronic microscopy(SEM). The results indicated that impact toughness, interlaminar shear strength and flexural properties were close re鄄lated to the resin content of aramid fiber reinforced composites. For F-8H3/602 aramid fiber reinforced compositeswith 46. 02wt% resin content, the impact toughness, interlaminar shear strength and flexural strength were 22 J/ cm2,49. 1 MPa and 506 MPa respectively. At certain weight content of resin, the mechanical properties of aramid fiber re鄄inforced composites in 0毅direction were much better than in 90毅direction. The interface between fiber and matrix of F-8H3/602 composites was weak according to SEM images of samples. -
2015, 45(2).
Abstract:
The mechanical property and mechanism of polyimide film in proton radiation was studied by 椎800combined space radiation test facility of Beijing Institute of Space Environment Engineering (BISSE) and X-ray Pho鄄toelectron Spectroscopy(XPS). The following results can be obtained: the rupture elongation and tensile strength ofpolyimide exponential decreases with the increase of proton radiation fluence, and its elastic modular keep steady.The polyimide film has good thermal stability in proton radiation environment, but its transmittance in ultraviolet andvisible range decrease and has red shift effect. The breakage and cross linkage of molecular bond is the major cause ofdecrease of polyimide爷s mechanical property in proton radiation environment. -
2015, 45(2).
Abstract:
A3 steel is used as the base material steel in electroless Plating of Ni-Co-P, The best formula andprocess conditions are acquired by using the orthogonal experiment methods. The morphology,corrosion resistance, hard鄄ness,thickness and binding force of coating are tested and analysed. The optimum formula and the technological conditionsare required as follows:35.0 g/ L NiSO4·6H2O, CoSO4·7H2O 4.0 g/ L, NaH2PO2·H2O 30.0 g/ L, Na3C6H5O7·2H2O60.0 g/ L, H3BO3 35.0 g/ L C3H6O3 12.0 mL/ L, C18H29NaO3S 0.05 g/ L, CN2H4S 2 mg/ L, pH value of 7.0, the tempera鄄ture of 90益, and the plating time of 2 h. Under this condition, the deposition rate is faster, up to 89.83 g/ (m2·h), thecoating has stronger corrosion resistance, copper sulfate drip experiment time is 285 s; the surface of the coating is smoothand uniform;the distribution of porosity is smaller;there is better binding force with substrate. -
2015, 45(2).
Abstract:
The performance and the microstructure analysis were carried out on 62Sn36Pb2Ag solder and63Sn37Pb solder used in silicon battery of analog sun sensor by mechanical test and accelerated thermal cycle test.Results show that the granulated Ag3Sn plays the role of dislocation pining effectively in 62Sn36Pb2Ag solder becauseof the addition of Ag element. In strengthening the joints, the granulated Ag3 Sn also improves the resistance to thethermal mismatch and the creep of the solder. After experiencing mechanical test and the temperature cycle test from-105 to +105益, the crack growth rate of 62Sn36Pb2Ag joint is much less than the 63Sn37Pb joint. Under the cer鄄tain test condition in the article, the resistance to the thermal mismatch and the creep of 62Sn36Pb2Ag is better than63Sn37Pb solder. -
2015, 45(2).
Abstract:
This paper takes H鄄bending waveguide as a typical component to study, the forming of special鄄shaped compo鄄nent. 138益of low melting point alloy used in the process of research as the core mould material to mold design and core mouldmolding parameter are found.The lamination process is simulated with DELMIA, which is benefit for saving the pre鄄assembly.The results show that using low melting point alloy as core has a high stripping efficiency comparing with chemical dissolvedcore, which make the batch production possible and provide the technical support for special鄄shaped components. -
2015, 45(2).
Abstract:
This paper analyzes the performance characteristics of CFRP and its impact on the cutting perform鄄ance. The selection principles of milling tool material and geometry are proposed, several milling tools which are suit鄄able for CFRP are introduced. Through a series of M40 defects testing and milling testing, influencing factors and lawsof M40 processing quality are summarized. The best processing parameters for each kind of milling tools machiningM40 are obtained. As a result, the condition of higher cutting speed and proper feed rate can improve M40 processingquality and efficiency. >测试分析
-
2015, 45(2).
Abstract:
Bright ghost defect were found on products which made of TA15 titanium alloy bar when macroscopictest. The microstructure is observed, by which the abnormal area for TA15 is principally determined . The chemicalcompositions of that area is charactered by SEM,and the microhardness is tested by microhardness tester. The resultsshow that the titanium content in the segregation is higher than that in the normal area, the aluminum content in thesegregation is lower than that in the normal area, and the Vickers hardness in the segregation area is lower than that inthe normal area, that is so called non鄄brittle segregation metallurgical defect . For the material of TA15 with segrega鄄tion structure, when the properties is according with the standard, the bar can be delivered as long as cut鄄off the seg鄄ment with segregation. -
2015, 45(2).
Abstract:
Both of the attaching loads and the coupling displacements of gravity in horizontal loaded static test forwind turbine blade is analyzed in this paper. The numerical results show that the superimposition of gravity has greateffect on the measured values, which lead to the risk of overloading the target load in some section. In order to reducethe overloading peak value of the equivalent load ,it is suggested that the comprehensive application of optimizing in鄄stallation angle of the blade and loading direction should be used based on FEM.
