Abstract:The progress of materials and processings for ablative polymer composite is introduced in this paper. The materials include ablation-resistant matrix resins and reinforcement, the processings include die moldings, tape wraps, layups and resin transfer moldings (RTM).

Abstract:In this paper, the problems of iridium coating in application and their impact on the current performance of the coating service were analyzed, three main types of modified iridium coating technology and iridium coating modification technology development in the future were discussed.

Abstract:The application and development of resin matrix composites for radomes are reviewed. The dielectric, mechanical and environmental property required for advanced radomes are presented, and various material systems are compared. Quartz/cyanate ester composite system's properties and environmental properties are presented in particular.

Abstract:A structural model of three layers angle interlock woven composites, was built by mapping software Pro/Engineer. The distribution of stress & strain on fibers, resin and 3D composites, was simulated and discussed, under shear loading using finite element software ANSYS Workbench. And the failure mode of composites was analyzed. The results show that, uniform shear deformation on the shear direction occur in the composites. The main loads were supported by reinforced fibers and the minor loads were supported by matrix resin. Compared warp yarns to weft yarns, warp yarns axial direction parallel to shear direction show larger stress and strain than those axial direction perpendicular to shear direction.

Abstract:During the preparation of continuous fiber-reinforced ceramic materials, the mismatch of linear expansion coefficient between the fiber and matrix may induce thermal residual stresses, which will result in fiber debonding and matrix cracking ultimately. And furthermore, it will have a significant influence on macro-mechanical properties. Based on the unidirectional C/SiC composites, this paper set a unit cell model of "fiber-interface-matrix" to predict the distribution rules of thermal residual stresses by micromechanics method. With ABAQUS software, the numerical simulation research on the preparation of C/SiC composites was developed, which revealed the influence rules of the interface thickness, fiber volume fraction and preparation temperature to the thermal residual stresses of the composites. And the effects of thermal residual stresses on mechanical properties of composites were also analyzed. The result is expected to provide a useful guideline for the design, evaluation and optimal application of C/SiC.

Abstract:One electronic equipment undergoes acceleration up to 38 g in flight vibration environment. To reduce the vibration response of the equipment, a new type of combined rubber damper is developed through FEM analysis and test verification. The results show that the random vibration response of the equipment decreases from 38 g to 11 g by using this damper, indicating a vibration reduction efficiency of 71%, and moreover the resonance amplification factor is less than 3.

Abstract:Fuselage skin is all-composite in Boeing 787. Repair programs for composite fuselage skin are given in Boeing 787 structural repair manual, including composite fuselage skin repair with titanium plates riveting. However, the maintenance theory of these repair programs and repair procedures, strength, stiffness and other mechanical properties of these repair programs are not described. Based on this, two dimensional finite element models of composite fuselage skin repair with titanium plates riveting are established in this paper. Stress size and distribution of matrix, patch and fill flat are analyzed on these two repair programs. Studies have shown that repairing large composite fuselage skin penetration crack with titanium plates riveting can meet the static strength requirements. Destroy sources of titanium patches of these two repair programs will occur at different locations.

Abstract:In this paper, the influence of carbon, fabric structure, resin and processing on the properties of carbon fiber uniaxial stitch bonded fabrics and its composite was studied. The results show that the fabric structural parameters, such as the types and the area density of warp carbon and weft material, have the same influence on the bending stiffness and the unidirectional permeability coefficient of the fabric. The No.6 epoxy resin compound based on TDE85 has obvious advantages than the other epoxy resin compounds based on Bisphenol A, on improving the unidirectional permeability coefficient of the fabric and the mechanical strength of the fabric composite. The mechanical strength of the fabric composite benefit from the process of hot-melt prepreg based on 610A resin, spreading of the warp carbon fiber and the carbon fiber of dry-jet-wet electrospinning process.

Abstract:In order to study the influence of process parameters on the quality of laser metal direct forming parts, the direct forming process of single-track single-layer GH3625 alloy was studied by orthogonal test. The influence of laser power, scanning speed, powder feeding speed and other parameters on the width and height of single-track single-layer forming cross-section was mainly studied. The forecasting model was proposed and confirmed. The results show that the process parameters such as laser power, powder feeding speed, scanning speed and so on are different in influence on forming cross-section. Among them, the influence of scanning speed is the most obvious. The experimental results show that the linear regression model obtained by Minitab software is effective.

Abstract:In order to study the compatibility of 2A14 alloy joint used on propellant tank, stress corrosion mechanism of aluminum alloy was analysized in this paper. The base metal, FSW joint and VPTIG joint of 2A14-T6 aluminum alloy were chosen to make corrosion experimentation with slow strain rate method. The result shows 2A14 aluminum alloy have stress corrosion tendency in 3.5% NaCl solution. And the corrosion resistance of FSW joint is better than VPTIG joint.

Abstract:The temperature of the optical system load is usually low.Low temperature surface is more easily contaminated by the outgassing molecules, which can degrade the performance and lifetime of the optical system load. Based on the diffusion theory and the classical adsorption kinetics theory,we achieve the adhesive depositing model, and then conduct an experiment on the condensation characteristics of adhesive. The experimental data is consistent with the theoretical model.This model can predict and control the contamination on low temperature surface to ensure normal operation of the satellites.

Abstract:Apparatus losing heat by fitting with heat pipe embedded in honeycomb sandwich panel.This article aimed to analyze the factors affecting the heat pipe area flatness in honeycomb sandwich panel.The dimensional precision of honeycomb core and the uneven thickness of adhesive film panel after curing are the main causes. The main solution carried out is increasing the thickness of average pressure tooling board, which can compensate the parts' cumulative dimensional deviation by adhesive film. The results showed that method could be applied to practical production.

Abstract:Aimed at the optimal technological condition of filament winding process for high modulus carbon fiber reinforced composite thin-wall cylindrical tube, the orthogonal experiments for winding process factors were designed and performed to confirm the order of these studied factors. According to the results of the further optimization tests, the metallographic test and tensile and compressive property tests, the synthetical performance of cylindrical tube reaches the optimization, when squeeze equipment gap is 0.1 to 0.2 mm,glue temperature is (40±2)℃, Winding tension is (10±2) N, the pressurized tape tension is 40 N.

Abstract:The friction stir welding process of 6 mm A356-T6 and 6061-T6 dissimilar aluminum alloy were study. And the joint organization and performance affects on welding speed and base metal position were investigated by using OM, SEM, universal tensile testing and micro hardness testing.The results show that no obvious defects and good appearance dissimilar aluminum joints could be acquire when the rotational speed of 1 000 r/min, welding speed about 100 to 400 mm/min were used. The material migration increased with welding speed decreasing, and A356 -T6 aluminum which located in advancing side was beneficial to transport materials. The joint consisted of nugget zone, thermal mechanical affected zone and heat affected zone,which are typical characterized organizations in FSW joints. The grain of weld nugget refined from surface to the bottom gradually. The tensile properties of the joints were increased with the welding speed increases. A356 alloy in the advancing side could be obtain higher strength joints at low welding speed, while higher strength were obtained at higher welding speed when 6061 in the advancing side. However,the yield strength and elongation of joint when A356 located in advancing side were higher than 6061 located in the advancing side. The fracture location of joints located in the heat affected zone of A356 side regardless of which base metal located in advancing side, and had nothing to the base metal location. And the hardness test exhibited that fracture location of joints correspond to the zone of the lowest hardness value.

Abstract:The traditional partitioning of MIG welded joint is very coarse. The understanding regions of welded joint has evolved tremendously. A fusion weld joint was thought to consist of three regions, the fusion zone and HAZ, which is not sufficient. Examination of a welded joint reveals several distinct microstructure regions in this paper. The fusion zone and HAZ is subdivided. The previous technological probes allow one to compare the effects of base metal, welding conditions, welding consumables, constrains and give answers in the "better-worse".

Abstract:Factors affecting the effect of repairing damage of composite materials are mainly layer angle, angle and adhesive patch. This paper aims at different patching slope of composite laminates using ductile adhesives Araldite^@2015. The repaired specimens using bending mechanical properties and tensile mechanical properties were evaluated. The results show that the overlay[±45°]_4s laminates under bending load repair efficiency can reach the highest of 119.6%, under tensile load repair efficiency can reach the highest of 71.4%; layer[0°/90°]_4s laminates under bending load repair efficiency can reach the highest of 82.1%. These results can provide the basis and guidance for the actual repair.

Abstract:After a deep study of the configuration and defect feature,a series of specimens with U notch in different angles is designed and manufactured. The emission acoustic fields of multi crystal plates in different refracting angles has been simulated. With the help of the M2M 256×256 Ultrasonic Phased Array facility and software platform Multi2000, the setting of Multi-Salvo is completed. And the client software which based on VC++6.0 has been developed, which can realize the real-time display and data storage of A-scan, and image fitting and real-time display of B-scan for specimen with special configuration. It becomes possible to achieve 100% inspection of Jacket Sections for ITER superconducting cables by the means of rotating the specimen for 90å after each-time inspection.

Abstract:The elastic modulus and hardness of interphase region for both Kevlar-49/epoxy and F-12/epoxy unidirectional composites were analyzed using quasistatic nanoindentation method. The results show that the height difference of aramid fiber and epoxy resin in longitudinal section of unidirectional composites is low. Therefore, the experimental error induced by indenter shape can be reduced, so that the mechanical properties of interphase region can be analyzed more accurately. The elastic modulus and hardness of interphase region are distinctly different from those of aramid fiber and epoxy resin. Based on the results of mechanical properties for fiber, epoxy and interphase obtained from nanoindentation, it is assumed that the width of property transition region is less than 1μm.

Abstract:A new requirement for defect detection has been proposed for the application of the new methods such as friction stir welding and laser welding. Furthermore, it is also necessary to realize long time storage and automatic processing after manufacture and servicing in the digital workshop. At present, the detection of X-ray detection method has many shortcomings, for example the film can not be preserved in long time, the evaluation is depend on the level of operators and the testing automatic level is not enough. In order to make the testing of internal defects in the rail vehicle welding structure, more visible and automatized a digitalized X-ray testing and evaluating method is proposed. In this paper, a new digitalized device of X-ray film is constructed and the film can be scanned into the computer at low information loss. Then the finding,measurement and recognition of welding imperfection, evaluation of film is realized. At last, a testing database is established also to record and look back the weld film information.