Abstract:In this paper, the characteristics of ultrasonic assisted machining technology and WPT technology are generalized, and the achievements of WPT ultrasonic assisted processing system is also summarized. An idea is proposed that the technology of magnetically-coupled resonant wireless power transfer (MCR-WPT) may be a more flexible and more ideal power supply mode.

Abstract:The bulk production of silver coated silica microsphere (SiO₂/PDA/Ag) was realized by dopamine-assisted functionalization and subsequent elelctroless plating. X-ray photoelectron spectroscopy (XPS), wide-angle X-ray diffraction (WAXD) and scanning electron microscope (SEM) results show that the silver layer on the surface of silica microsphere was homogenous, continuous and compact with stable silver contents. The surface of SiO₂/PDA/Ag microsphere was much rougher than the one imported from U.S. The roughness will facilitate the electron tunneling effect of particles. The SiO₂/PDA/Ag microsphere maintains its intactness and strongly adheres to ethyl vinyl silicone rubber after the blending with silicone rubber. The mechanical and electrical characterizations of conductive silicone rubber show that tensile strength is 2.54 MPa, elongation at rupture is 122.3%, volume resistivity before and after thermal aging is 3.9 and 9.0 mΩ·cm.

Abstract:In order to prepared the phenolic foams with excellent cell structure and mechanical properties, the graphene/silica (GNPs/SiO₂) hybrid materials were prepared by the method of in situ formation. The graphene and GNPs/SiO₂ hybrid materials were used in the preparation of phenolic foams. The cells structure and compression properties of the phenolic foams were analyzed,and found that hybrid materials can improved the bubbles structure and mechanical properties more effectively. and the Infrared Spectroscopy(FT-IR),transmission electron microscopy (SEM) and X-ray diffraction (XRD) analysis were conducted and confirmed the silica spheres were formed on the surface of the GNPs. The silica shows a particle size of 150-180nm. The phenolic foams showed more uniform cell structure and small cell size when the content of hybrid materials was 0.5wt%. GNPs/SiO₂ modified phenolic foams showed the excellent mechanical properties than the graphene modified phenolic foams. The compressive strength and modulus of 0.5wt% graphene/SiO₂ modified phenolic foams was 0.22 and 4.11MPa, which has increased by 91% and 86%, respectively, compared to the pure phenolic foams.

Abstract:In order to study the effect of discontinuous hygrothermal on properties of T700/TR1219B composite, the specimens were treated with discontinuous hygrothermal treatment. The tensile test was carried out and SEM was used to observe the lateral morphology. The nano-indentation test was conducted by peak force quantitative nano-mechanics technique (PF-QNM) of atomic force microscope (AFM) to analysis the discontinuous hygrothermal effect on properties of resin. The results show that when the rate of moisture absorption varies from 0% to 1.2%, the first time and the second time moisture absorption of T700/TR1219B composite follow the Fick law. Tensile strength and elastic modulus of specimens and hardness and elastic modulus of resin increase firstly and then decrease.

Abstract:By applying wet hand lay-up process with glass fabric reinforced epoxy, a kind of composite structured large radome was developed. The results of electric property testing and static testing show the selection of material, structure design and process are feasible. The minimum power transmission efficiency of the radome is 87%; The 120% designing load testing was successful.

Abstract:Through the design of carbon fiber composite lay-up and forming process, a cavity-metallized high-precision and complex composite resonator for a satellite was fabricated by metal transfer from mold surface. High and low temperature experiments were carried out on the composite waveguide resonator. The results indicates that the cavity surface precision, flatness and metallic coating bond strength of the resonator satisfy the design specifications. After 100 cycles of high and low temperature,metallic coatings and CFRP substrate maintain good adhesion. CFRP resonator weighs 72% lower than its Invar counterpart.

Abstract:In order to improve the flame retardant property and ablation property of silicone rubber coated fabrics, the new flame retardant silicone rubber coated fabrics were made by adding the flame retardant in the silicone rubber, and the flame retardant property and ablation property of them were tested and comparatively analyzed with military silicone rubber coated fabrics. The result shows that the flame retardant property of new flame retardant silicone rubber coated fabrics W-1 and W-2 are better than military silicone rubber coated fabrics J-1 and J-2 obviously with the oxygen index higher; the ablation property of two kinds of silicone rubber coated fabrics are similar, the temperatures of discontinue heating of the former are lower, but the highest temperatures are higher, and the ablation phenomenon are similar.

Abstract:In order to solve the problem of the edge defects of SiC_p/Al composites with a volume fraction of 20%, a single factor experiment was carried out to study the influence of cutting parameters on the edge morphology. The results show that the shape of the exit edge is greatly affected by the change of milling speed, and the edges are good at low speed and high speed; when the feed rate is 0.02 and 0.04mm/r, the exit edge are burrs. With the increase of the feed, the edge has serious defects and surface spalling, and then a small number of burrs and defects. When the axial depth of cut is changed, there will be serious defects in the edge of the outlet, and only changing the axial cutting depth has little effect on improving the quality of the edge morphology.

Abstract:The conductive silicone rubber were prepared with the conductive filler of Ag/Ni/glass microsphere.The morphology of conductive silicone rubber was characterized. The electrical property,electromagnetic shielding property and mechanical property of conductive silicone rubber were studied. The results illustrated that the shielding effectiveness of silicone rubber with Ag/Ni/glass microsphere increased in low frequency due to the presence of nickel,the electric conductivity and mechanical property of conductive silicone rubber were excellent and the electromagnetic shielding effectiveness was (70.6 to 98.8)dB in frequency of 10kHz to 6GHz when the volume fraction of filler was 56%.

Abstract:The welding craft equipment structure of the existing wainscot flange is simple and has small pressing force using the welding method of manual welding, while great residual stress and deformation can be obtained in the seam after welding, resulting in bad stability of welding quality. Therefor it can not meet the demand of the products. This paper starts from the influence factors upon flange welding quality, a flange automatic welding craft equipment was developed. Basing on the simulation methord the optimal interference fit quantity of 0.15 to 0.25mm between flange and the aperture has been obtained. The methord of installing wainscot firstly and then flange can effectively prevent the assembly cracks. Heating the bearing plate before welding solves the problem of priming cracks. The appearance of the flangewhich welded by automatic welding process is beautiful, while welding defects are reduced by more than 70% compared with manual welding. The average tensile strength of welded joints at low temperature (-196℃) reached 348MPa, and the elongation reached 6.7%.

Abstract:Common high-performance thermal protection materials have relatively weak mechanical properties, which became the bottleneck of aircraft thermal protection system development. Therefore,to design thermal protection materials with both good insulation effect and enough load capacity the become current research hot spots. In this paper, the stress-strain curve of the C/C thermal protective composite (C/C composite) was obtained by the uniaxial compressive experiments in order to investigate the compressive deformation and fracture model of C/C composite. Moreover, the microscopic morphology and microstructure deformation of this material were also studied by the SEM observations of the original material and fracture section, which also provide an experimental foundation for the characterization of the internal microstructure to establish the numerical geometric model and FEM simulation. The experimental results show that the fibers in C/C composite are randomly distributed along in-plane direction, which cause the obvious stratification. The mechanical properties of C/C composite in the in-plane direction are superior to those in the out-of-plane direction.

Abstract:Surface properties of carbon fiber/cyanate ester (CFCE) were investigated after exposure to hyperthermal atomic oxygen. SEM and XPS were used to characterize the chemical and physical changes of the surface of the material. The results indicated that the erosion yield of CFCE is (2.20±0.36)×10^-24 cm³/atoms. The relative atomic concentration of C and O, increase and decrease respectively. The surface got rougher with increasing AO fluencies, and as carbon fiber exposed to hyperthermal atomic oxygen, the surface tended to shape cavities, and link ravines finally. The scattering tests show that the productions of CFCE to hyperthermal atomic oxygen are CO、CO₂、H₂O、OH and CH₃.

Abstract:Surface modification of silicon power is an efficient approach to improve the dispersion and compatibility of silicon in epoxy matrix. FT-IR and EDX analyses show that silane coupling agent had been grafted on the surface of silicon. The coefficient of thermal expansion of epoxy encapsulant had changed from 83.9×10^-6/K to 41.8×10^-6/K,decreasing approximately 50.1%.An optimization of workmanship had been done and showed as following: operating temperature is 60℃ and operating-time is up to 3h;curing program is 65℃/2h+105℃/4h+135℃/2h.

Abstract:In order to investigate the machinability of high silica glass fiber/phenolic resin composites,the turning process of the large diameter thin-wall rotary parts is carried out.The experiment was done with four kinds of cutting tools, the effects of different cutting parameters and cutting tool materials on cutting force are obtained. The results demonstrate that in three cutting parameters, cutting depth has the greatest influence on cutting force, followed by cutting feed, and the cutting speed is very small. The optimal cutting parameters can be obtained when v=119.32mm/min, f=0.1mm/r and a_p=0.5mm. Ti-Al-Si-N nano coated carbide and super-hard material F2HX uncoated carbide tools are suitable for cutting the material at the low cutting speed, the PCD tool is suitable for high speed machining.

Abstract:The non-contact ultrasonic Lamb wave method can detect the large area composite sheet quickly and has the outstanding advantages in the automatic imaging detection. A0 mode lamb waves were excited by air-coupled ultrasonic probes for carbon fiber reinforced resin (CFRP) composites laminates. The Lamb waves were scanned and detected on the same side of the sample with the impact damage, and the Lamb waves were scanned in two directions which are orthogonal to each other to obtain the detection signals at different positions. Based on the characteristics of the Lamb wave propagation signal in the without defects and with defects plates, the frequency domain analysis of the acquisition signal is carried out. It is caculated for signal difference coefficient (SDC) based on no defects area signal.And SDC is used as characteristic value, the scanning imaging is achieved form characteristic value by using full summation algorithm and full multiplication algorithm data fusion method. Contrast of the amplitude imaging scan,the SDC imaging results are able to reflect the position of impact damage more,and it can show the impact size in two directions.

Abstract:The manufacturing process and defect types of graphite materials are introduced in this paper, combining with the working characteristics of the liquid rocket engine face seal, the necessity of testing the internal defect of graphite material for face seal is expounded. A comparative analysis is made on the present nondestructive testing methods, the X-ray detection method is the best for liquid rocket engines face seal. The key parameters of the X-ray detection such as gray scale, contrast, voltage, current, filter slice and integral time are compared and analyzed, then the process parameter setting rule and the high precision detection method of the internal defect inspection of graphite material are confirmed.And a visual simulation analysis of the internal space of graphite material is realized.And method for calculating the rate of porosity of graphite materials based on image processing.Finally the characteristics of graphite material internal defects typical of standard samples input forward of liquid rocket engine face seal are established.

Abstract:The adoption of original weld method usually causes the low pass rate and poor reliability of the collector for propellant management device. In order to solve the problem, resistance seam welding tests between titanium alloy bearing plate and stainless steel screen with pure titanium interlayer were performed. Subsequently, electron beam welding tests between the two and titanium alloy frame were performed. Then vibration tests in terramechanical environment were performed to verify the effectiveness of the addition of the pure titanium interlayer. The welding tests results show that the pure titanium interlayer could significantly reduce the welding heat during the resistance beam welding process and further reduced the hot deformation of screen. In addition, the interlayer could form a firm and enclosed pure titanium and stainless steel transition, which could effectively increase the deformation resistance of the screen during the electron beam welding process and further improve the percent of pass and property of welded samples. The vibration tests results show that the improved welding method could increase the lower confidence limits for reliability of collector from 0.90 to 0.96.

Abstract:The ultrasonic testing technique of structure/damping integrative composites has been studied in this paper. It has been found that delamination defects in the composites and debonding defects between the composites and damping layer could be detected efficiently by pulse echo technique and transmission technique.