Abstract:The application status of advanced resin matrix composite in satellite antenna system is introduced in this paper. Based on the researches of Beijing Institute of Space Mechanics & Electricity, difficulties of composite materials for engineering application are summarized. The major issues must be solved about design and processing and space environmental applicability are also discussed. 

Abstract:An effective mesh parameterization approach is proposed for the meshes which contain holes and ir
regular boundaries could not be parameterized well by the convex combination approaches. The whole holes would be filled by fitting variational implicit surfaces and a simple additional boundary is constructed for the mesh,and then the parameterization result will be obtained by a convex combination parameterization method. The experimental results in dicate that the new introduced vertices can be used as the supplementary data to fit surface smoothly. Furthermore, the proposed method has been used to the parameterized surface construction during the fast design of composite mold.

Abstract:In this paper, the microwave absorption properties of three different types of carbon nano materials such as U carbon, carbon nanotube and carbon black have been studied at the frequency band of 8 to 18 GHz. The complex permittivity of carbon nano materials/ paraffin composite with different weight fractions were measured at the frequency band of 8 to 18 GHz. The results show that the real and imaginary of the complex permittivity of the com posites were increased with filler weight and the increasing rates of the real and imaginary part with respect to the filler
weight were all different. These different rates have great effect on the thickness in the designing the single layer mi crowave absorbers. The match thickness of coating and the weight of filler were obtained by the Cole Cole plot. When 20% mass fraction carbon nanotubes were used with coating thickness of 1. 6 mm, the reflection loss is superior to -10 dB at 11. 2 to 15 GHz and the maximum reflection loss can reach -29. 6 dB.

Abstract:In this paper, theoretical analysis and experiment verification were combined to analyze the sawing force of SiC wafer cut with electroplated diamond wire saw under workpiece rotating condition. Based on the grinding and dynamic cutting theory, the motion model of wire saw and workpiece, the radial and tangential force of a single diamond grain were analyzed, and then the SiC wafer sawing force model was built. The SiC wafer sawing experiments with workpiece rotating were carried out to verify the theoretical analysis, the influence of wire saw velocity, work piece feeding, workpiece rotating and the uncut part of the workpiece on the tangential force were emphatically ana lyzed. The results show that the relative error between the theoretical analysis and experimental result is no more than 5. 2%, thus the correctness of the established model is verified, which will provide basis for exploring the SiC wafer cutting mechanism and parameter optimizing

Abstract:A novel phthalonitrile functional biphenyl type novolac resin (PBN) was synthesized by nucleophilic substitution reaction between 4 nitrophthalonitirle and bipheny type novolac resin using base as catalyst. The results of rheology show that the complex viscosity of PBN resin is below 400 mPa·s at 180 to 300益,indicating that the resin possesses excellent processing capability. DSC curve of PBN resin reveales that the thermal polymerization reaction oc curs between 280益and 450益with peak temperature of 377益and exothermic enthalpy of 187 J/ g. PBN resin exhib ites excellent thermal stability. The results of TGA shows that Td 5 and R900益are about 529益and 78%,respectively

Abstract:Rheological behavior of a silicon containing arylacetylene resin( PSA) is very important for RTM
molding. The curing properties and relationship between viscosity of the resin and time were studied with DSC analysis and viscometer measurements respectively. The results shows that PSA resin is a typical Newton fluid and has a low viscosity platform from 100益to 130益. A Dual Arrhenius viscosity model has been established to describe the rela tionship among viscosity, temperature and time. The estimated viscosity values of the established model are in good a greement with the experimental ones. This equation of the model can be used as a guide for the RTM molding of PSA.

Abstract:The curing characteristics of unvulcanized filled silicone rubber were investigated by a Dynamic Me chanical Thermal Analyzer (DMTA) called RSA3 instead of curemeters. The influence of curing agent type on the cu ring characteristics of silicone rubber when choosing polyvinylsilicone oil, namely C gum, as concentrative crosslinker were studied. And the differences of crosslink reactions of rubber with three different curing agents were also dis cussed. The results show that benzoyl peroxide (BPO) can爷t well cure silicone rubber with C gum. While the di cumyl peroxide (DCP), one vinyl鄄specific curing agent, can well cure silicone rubber with C gum. The best cure
effect in the presence of concentrative crosslinking of silicone rubber of this research is a combination of DCP and BPO. The silicone rubber cured with the combination of BPO and DCP have high modulus, and the rubber can be cured by two cure stages of low and high cure temperature without cure reactions rate decreasing.

Abstract:The high temperature resistant repair coating was prepared by using epoxy resin and furan resin as matrix respectively,which was mixed with SiC powder and whisker. The ablative resistance property was investigated by using oxyacetylene ablation equipment. The materials and microstructures of the ablated samples were characterized by X-ray diffraction, energy dispersive spectroscopy and scanning electron microscopy. It is found that the furan res in/ SiC coating with the mass ratio of SiC powder and whisker is 8/ possesses excellent ablative resistance property.
The linear and mass ablative rates are 28 滋m/ s and 66 mg/ s,respectively. The compact SiO2 layer generated during the ablation process can cover and protect the matrix. The furan resin/ SiC coating can be used to repair the damaged structure of TPS.

Abstract:By using pitch based carbon filaments as the substrate in cold wall chemical vapor deposition
process, silicon carbide filaments were prepared from methyltrichlorosilane and hydrogen system. The effect of deposi tion temperature (from 1 473 K to 1 773 K) on microstructure of as prepared fibers was investigated by scanning elec tron microscopy and Raman spectrascopy. The results shows that the main crystalline phase of coating is SiC. The increase in deposition temperature leads to the increase of deposition rate and the enlargement of grain size of SiC coat ing. Meanwhile, as the deposited temperature increases, the microstructure rearrangement of the central region of car bon core results in the decrease of grain size and better orientation.

Abstract:To improve the mechanical properties of high modulus carbon fibers, the interface bonding abilities of cyanate ester, epoxy 5228 and epoxy 4211 with carbon fibers were studied. In this paper, SEM, AFM, micro鄄dissoci ater and all鄄purpose mechanical tester were used to investigate surface micro configuration of carbon fibers, and the micro鄄bonding of resin matrix and carbon fiber surface. The macro mechanical properties of composites were also stud ied. It is found that with the increase of carbon fiber modulus, defects and channels on the surface decrease, surface
activity drops and the bonding strength with resins is weaked. The bonding properties decrease with the order of modi fied cyanate ester, epoxy 5228 and epoxy 4211. The higher the bonding strength of resin with fiber, the better the mechanical capabilities of composites.

Abstract:High water absorption for thermal insulations will decrease thermal insulating and mechanical proper ties. In this paper,the effects of components on water absorption were investigated. Moreover,regarding to the problem of high water absorption,thermal treatment and hydrophobic nano鄄silica were adopted to solve the problem. The results indicates that nano鄄alumina and E鄄glass has little effect on water absorption of the composites,and water absorption will increase with the addition of zirconite. Heat treatment can decrease the water absorption to some extent,but should
be tightly controlled below 800益. The introduction of hydrophobic nano鄄silica can significantly decrease water absorp tion and shorten absorption balance time. Furthermore, better results can be achieved with the increase of additive a mount of hydrophobic nano鄄silica.

Abstract:A 3D FEM model of Ti75 alloy tube spinning was established. The distribution regulation of stress
and strain during spinning process was analyzed. The influences of feeding, reduction and angle of roller on spinning process were obtained. The force and piling distance of spinning increased with increasing roller angle, feeding speed and reduction ratio. The PEEQ increased with increasing reduction ratio, decreased with increasing feeding speed.The PEEQ is hardly changed when feeding speed is above 1mm/ s. The PEEQ is almost constant when the roller angle are smaller than 20 degree. The PEEQ increased quickly with roller angle when the roller angle exceed 25 degree.

Abstract:To achieve the required surface characteristics, the experiment and simulation researches on effects of drilling processes on surface quality of aircraft fastener holes drilled on 7075-T7351Al alloy were conducted from the perspective of surface integrity and fatigue life. Compared conventional multi鄄step drilling processes with Winslow, it is found that there are smaller roughness vales (Ra), less operation defects, larger compression residual as well as higher fatigue strength on the machined surfaces produced by multiple鄄step with slow feed (DBM) and Winslow,and
Ra of Winslow is lower than 60%, fatigue limit is 23% higher than that of DBM. Based on test data, two empirical formulas affecting roughness and residual stress are established, and strain distribution and temperature variation are analyzed by numerical simulation. In addition Winslow strengthening mechanism are discussed. It is put forward that appropriate increase in cutting speed or decrease in feed rate can improve surface quality of fastener hole

Abstract:The microstructure of QCr0. 8 and 1Cr21Ni5Ti joint by electron beam welding was analysed and in鄄
vestigated. Compared with the joint which formed without interlayer,the joint based Ni slice interlayer had a transition zone where the microstructures and elements distribution changed by degrees. As a result,the mechanical properties of QCr0. 8 /1Cr21Ni5Ti EBW joint are improved.

Abstract:A broadband complex permittivity measurement technique of low loss dielectric materials at low mi
crowave frequencies using the reentrant cavity is presented. The testing system is established and several materials are measured by the system. It is proved by the experiment that the presented method is valid. The method features high accuracy,small size and the sample is easy to place.

Abstract:In order to enhance the heat resistant and mechanical properties of honeycomb sandwich at high temperature,the test of mechanical properties and heat insulation properties with static quartz lamp are carried out. The result shows that the retaining rate of flexural strength,moduli and interlaminate of panel are 58%,85% and 57%,respectively. After the sample heated by static quartz lamp,with 300 kW/ m2 and 168 kW/ m2 heat flux for 180 s,the back temperature of honeycomb structural composites are 320益and 296益,respectively.

Abstract:The self鄄lubricating composites which were made up of enhanced resins and blend fabric woven by
high strength fiber and PTFE fiber were investigated. Moreover, wear experiments were carried out by using speci mens made of the composites at high loads. The influence of surface temperature, stress, frictional coefficient and compressing properties in terms of different kinds of high strength fibers and resins was also studied. In addition, the mechanism of reducing friction coefficient was analysed because of “ PTFE transferd lubricating films of the compos ites冶. The results showed that the comprehensive properties of the composites made by blend fabric A and modified phenolic resin were excellent,and the films were found on the surface of the composies in the course of the friction at high loads. The friction coefficient arrived at 0. 018 eventually.

Abstract:The microstructure change of chlorinated rubber coating under artificial accelerated aging was charac terized by using impedance spectroscopy and infrared attenuated total reflection(ATR). The result indicats that after thermal oxidative aging in 130益,the chlorinated rubber coating released HCl gas and carbon鄄carbon double bond is formed. After hydrothermal aging in 85益,RH=75% besides the releasing of HCl gas and formation of carbon鄄carbon double bond, hydroxyl is found in the coating.

Abstract:Monothetic SiC,Cu,and SiC/ Cu laminated composites with different SiC layer thickness were synthesized by magnetron sputtering. The microstructure of the SiC/ Cu laminated composites were characterized by SEM and XRD. In dentation test and tensile experiment were carried out on micro鄄hardmeter and electronic universal testing machine(IN STRON),respectively. The experimental results show that clear interfaces are formed in SiC/ Cu laminated composites. Com pared with monothetic SiC,the toughness and tensile strength of SiC/ Cu laminated composites can be improved,however,the
hardness decreases. From the examination of fracture surface reveales that crack deflection,bridging,plastic deformation of Cu ductile metal layers are main reasons to improve the tensile strength of SiC/ Cu laminated composites.

Abstract:The density, structure, chemical element analysis,mechanical, physical and friction properties of a certain type of aircraft brake material 鄄a beryllium alloy were investigated. A comparison of some performances be tween C/ C composites, C/ SiC composites and the Be alloy made by powder metallurgy(PM) was made and the re sults show that beryllium alloy has low density, excellent mechanical and friction properties,and is a potential brake material

Abstract:The mechanical properties of 7085 aluminum alloy have been obtained by high temperature tensile
test. The quenching process of 7085 aluminum alloy aircraft forging with frame and beam structure has been simulated by FEM code ABAQUS. The influence of different quenching technologies on the magnitude and distribution of quenching residual stress has been investigated. The results show that the residual stresses of the forging are mainly concentrated on the interface of the rib and web with the characteristics of external compressive and inner tensile. The quenching temperature has significant influence on the magnitude of residual stress, and improvement of quenching
temperature is beneficial to decreasing the residual stress. The solution treatment temperature, the method of entering water and the transfer time for large鄄size aircraft forging with frame and beam structure have little effect on residual
stress.

Abstract:According to the brittle and hardness character of optical glass, the removal mechanism is discussed .The experimental result show that a high removal rate and the smooth high quality surface can be obtained under ultra sonic lapping