Abstract:This paper reviews the development of research on the composition and detection of interphase， and binding strength of metal matrix composites. Furthermore， existing cohesive models for characterizing the interphase of metal matrix composites are analyzed based on traditional fracture mechanics. On this basis， the cohesive constitutive relation and parameter acquisition method are described， as well as the application of simulation in the interphase of metal matrix composites， and the focus and direction of future research are proposed.

Abstract:First， the influence of grinding parameters， fiber direction， different processing methods and other factors on grinding force and surface quality in grinding process was reviewed. Then， the grinding mechanism of carbon fiber ceramic matrix composites with different processing methods was summarized. Finally， the further research direction of grinding carbon fiber ceramic matrix composites was prospected.

Abstract:The bending curve of flexible plate was calculated by numerical integral method at the specified bending moment and shearing force， based on the deflection equations of beams according to the mechanics of materials. The length of plate was also derived by line integrals in the meantime. Then the bending curve， moment and shearing force can be finally determined relative to the given length and span. The finite element software was employed to simulate the same model under the same conditions. Compared to the results of finite element method， it is found that the bending curves by numerical calculation were almost identical， in addition， the precision of the moments and forces can meet the practical demand in engineering. All the parameters of bending plate can be used for further analyzing and estimating based on the above numerical calculation method， which is valuable for guidance in the practical engineering applications.

Abstract:Ca_0.7La_0.2TiO₃ （CLT） was respectively hydroxylated （CLT—OH） by 30% H₂O₂ and modified （CLT—VT） by Trimethoxy（vinyl）silane （VTMS）. The hydrophilic and hydrophobic layers are respectively obtained on the ceramic surface， and they form hydrogen bonding and physical adsorption with the resin. By melt casting method， the modified ceramics and vinyl silicon-containing aryne resins （PSAE） were prepared into a series of microwave dielectric composite materials with different dielectric constants. The effect of different ceramic/resin interface forces on the properties of composite materials was studied. It was found that 40 vol%CLT—VT/PSAE achieved the best dielectric performance at 10 GHz， with a dielectric constant of 13.8 and a dielectric loss of 3.16×10^-3 and 40 vol%CLT—OH/PSAE has obtained the best overall performance， with a bending strength of 50 MPa， a dielectric constant of 14.77， and a dielectric loss of 3.29×10^-3.

Abstract:The bonding interface of space silicone rubber and polyimide exhibited low surface energy，which lead to destruction of sticky structural parts.In order to improve the bonding strength， the interface was pretreated with organosilane as adhesion promoter.The structure and composition of organosilane were analyzed by FTIR， ¹H-NMR，and the shear strength performance tests were carried out to test the physical properties of the encapsulated materials treated with organosilane.The results showed that the main components of organosilanes had a great influence on the bonding properties of tetrabutoxysilane and glycidoxypropyl-trimethoxysilane.The surface of the polymer was pretreated with two silane coupling agents， and a molecular bridge was formed between the heterogeneous polymer layers by silane interdiffusion and interpenetrating networks to achieve dense cross-linking.The shear strength showed that the shear strength could reach 0.65MPa，and the failure modes were adhesion failure.Therefore， an appropriate silane coupling agent can be selected as the adhesion promoter， and the packaging reliability of the non-polar polymer can be improved by utilizing the organic functional group， film formability and crosslinkability.

Abstract:In order to investigate the effects of process parameters on the temperature distribution of the composite wound-layer， the classical thermodynamic theory is adopted to analyze the heat-transfer mechanism during the prepreg tape winding process. Based on the law of periodically winding， the model of temperature distribution is established with the change of the initial boundary condition of the old layer. And the accurate numerical solution of the one-dimensional heat transfer model is obtained using Matlab programming. According to the model， the influences of initial winding temperature， winding speed， and mandrel temperature on the temperature change of the wound-layer are discussed theoretically. The results show that that the level of influence on the winding layer temperature is mandrel temperature >winding speed> initial winding temperature. Moreover， no matter how the parameters change， the temperature distribution of the winding layer is always lower in the inner layer. As the radial position increases， the temperature of the winding layer gradually risers， and reach the maximum temperature in the outer layer. Besides， the temperature model proposed in this paper meets engineering requirements and can offer a guideline for the winding process through a comparative analysis of experiments.

Abstract:Phase structure and micro-morphology of carbon nanotube film （CNTF） prepared with the chemical vapor deposition （CVD） method were characterized. According to the micro-structure characteristics of carbon nanotubes in CNTF， which are disordered and arranged irregularly， but have high porosity， the design scheme and preparation process of aircraft electro-thermal anti-icing system based on CNTF are proposed. In this program， light materials such as CNTF and epoxy resin were used， and the sample preparation process was discussed and optimized. The electro-thermal performance of this new type of electro-thermal anti-icing system''s sample was studied through the test of electro-thermal heating characteristics and anti-icing function tests. The results show that this new type of electro-thermal anti-icing system has simple structure and light weight， and is easy to be combined with aircraft aluminum alloy skin， which is conducive to reducing aircraft empty weight and flight cost. The effective average temperature obtained in the electric heating process is 47℃， which can effectively accelerate the melting of ice layer and has a good prospect in practical application.

Abstract:A356.2（Sc，La） aluminum alloy was prepared by casting process. The refining effect of rare earth elements Sc and La on eutectic silicon and mechanical properties of aluminum alloy was tested and analyzed. The results show that the addition of rare earth element La alone can refine eutectic silicon in A356.2 （La） aluminum alloy to a certain extent， but has little effect on the improvement of mechanical properties. However， the eutectic silicon in A356.2 （Sc， La） aluminum alloy containing 0.38% Sc and 0.14% La has better refining effect and higher mechanical properties， The eutectic silicon is refined to 2.3 μ m. and the tensile strength and elongation reached 181.6 MPa and 4.0% respectively.The refining effect of rare earth Sc and La on eutectic silicon is mainly the result of both dispersion strengthening and fine grain strengthening， which are related to the precipitation of Al3Sc phase and rare earth La phase in aluminum alloy.

Abstract:The 20 mm thick 2219 C10S aluminum alloy sheets were subjected to friction stir welding. The internal defects， macroscopic morphology， microstructure， micro-hardness and tensile mechanical properties of the welding joints at the speed of 400~550 r/min were compared under the condition of a travelling speed of 100 mm/min. The results show that when the rotation speed is 400~500 r/min， the welded joints with no defects and higher internal quality can be obtained. As the speed increases， the distance between the "onion rings" in the weld nugget zone and the range of the shoulder affect zone increase， and the micro-hardness of the weld nugget zone and the thermo-mechanical affect zone decreases more obviously. The tensile mechanical property of the joints decreases with the increase of the rotation speed. The maximum tensile strength can reach 334 MPa. The fracture mode of the joint is mainly ductile fracture occurring at the junction of the thermos-mechanical affect zone and the heat affect zone on the retreating side. It coincides with the position of the minimum micro-hardness. Point defects were observed on the surface of the weld joint when the rotation speed increased to 525 r/min and continuous furrow defects were observed inside the weld joint when the rotation speed increased to 550 r/min.

Abstract:Based on the aluminum alloy components in the space propulsion system， the characteristics of threshold of laser welding are studied. Results show that the threshold interval of laser welding for aluminum alloy is positively correlated with the welding speed and the absolute value of defocus， but the magnitude of the positive change is much lower than that of stainless steel， nickel alloy and titanium alloy. For laser welders with different beam qualities， the smaller the focal spot diameter of the beam， the lower the threshold interval during real-focus welding； the smaller the divergence angle of the beam， the lower the threshold interval under the same defocus amount. In the range of -12° to 12°， the threshold interval of laser welding for aluminum alloy has nothing to do with the incident angle. The blowing direction and blowing speed of shielding gas basically do not change the threshold interval of laser welding for aluminum alloy， which is different from stainless steel.

Abstract:The manual degolding and tin-coating of inter-board connector has the problems of low efficiency and poor quality. By analyzing the advantages and disadvantages of several kinds of tinning methods for inter-board connector， a new method of developing protection device and using tin pot for tinning is proposed. The key technology of protection device development and implementation process are described in detail. The results show that this process method has the advantages of simple operation process， low difficulty， good process stability， few rework and repair， greatly improves the quality and efficiency of tinning， and the protective device can be reused， which reduces the cost of tinning.

Abstract:In this paper， a study on surface quality of chopped carbon fiber phenolic composites was carried out with the help of 3D measurement technology and orthogonal cutting test.The effect of three elements of cutting and tool nose arc radius on machining quality was researched.Significant factors on machining factors was analyzed through Design Expert. It is found that with the increasing of cutting speed and feed rate the corresponding surface roughness is increased， but reduced with the increasing of cutting depth and tool nose arc radius.The significant factors are tool nose arc radius and feed rate.The best combination of machining parameters are v=160 r/min，f=0.15 mm/r， a_p=0.6 mm， r=0.6 mm，and the conclusions are reliable by implementing cutting test and modeling analysis.

Abstract:In order to research the effects of the thickness and stiffness of the side coating and strain isolation pad on the mechanical properties of the rigid thermal insulation tile and its components， a rigid thermal insulation tile analytical model with a symmetrical structure was constructed， finite element analysis（FEA） and static tensile test were carried out. The FEA results showed that the stress distribution of the rigid thermal insulation tile was not uniform under the action of tensile load， and there was obvious stress concentration， and its tensile strength level was closely related to the maximum stress. With the increase of coating thickness or stiffness， the maximum stress of the rigid thermal insulation tile increased， and the tensile strength decreased. When the rigid thermal insulation tile was bonded to the strain isolation pad， the maximum stress of the rigid thermal insulation tile decreased， and the tensile strength increased， while the thickness of the strain isolation pad increase or the stiffness decrease. When the rigid thermal insulation tile was coated， the strain isolation pad would reduce the effect of the coating on the rigid thermal insulation tile. The finite element analysis results were verified by static tensile tests， and the calculated results agreed well with the test results. The results showed that the analytical model was reasonable，the failure of the rigid thermal insulation tile were correlated with the coating and strain isolation pads.

Abstract:In order to investigate the effect of glue joint repair on the flexural deflection of carbon fibre composite laminates， tests were set up with two types of laps， step lap and diagonal lap， to investigate the flexural deflection of the glue joint by means of three-point bending experiments and digital image correlation （DIC） techniques. The results showed that the failure load and bending strength of the step-lap specimens were lower than those of the diagonal-lap specimens for the same lap length.The bending deflection of the specimens was related to the strength and lap length， with the longer the lap length， the higher the bending strength and the lower the bending deflection. This shows that the longer the lap length， the higher the strength of the glued laminate， but not conducive to the flexible deformation of the laminate.

Abstract:In the assembly process of aircraft parts， the connection of CFRP/ titanium alloy laminated structure is very common. Due to the very different material properties of the two materials， the pore size order difference exists after hole making， which seriously affects the fatigue strength of CFRP/ titanium alloy structure. In this paper， the orthogonal experiment of low-frequency vibration-assisted drilling was carried out， and the relationship between the technological parameters of low-frequency vibration-assisted drilling and the cutting force and chip morphology was analyzed， as well as the influence of technological parameters on the pore size difference of CFRP/ titanium alloy. The results show that titanium alloy chips change from long continuous chips to short sector chips due to the periodic feed of low frequency vibration-assisted drilling tool， cutting heat in drilling area decreases and average axial force decreases. In addition， the influence of amplitude and feed on the aperture order difference is relatively significant， while the influence of spindle speed is relatively small. Moreover， the aperture order difference first decreases and then increases with the increase of amplitude， and then increases with the increase of feed. Through test verification and analysis， the optimal process parameter combination scheme for aperture control-oriented is determined： spindle speed is 600 r/min， feed is 0.02mm/r， and amplitude is 150 μm.

Abstract:The composite hole circumference of the composite double-bolt joints structure is easy to be damaged due to uneven loading and complex stress state. The penetrate area is usually the weak link of the connection structure. The connecting hole is generally reamed to a standard size circle during aircraft structural maintenance. Thus it is of great significance to study the rules of corresponding distribution and factors of hole influencing after double-pin reaming maintenance. This is of great significance to ensure the airworthiness of structural components and improve the connection performance. This paper took the composite material/aluminum alloy connection structure as the research object， and built a three-dimensional progressive damage analysis model of double-bolt single-shear connection with embedded Hashin failure criterion and improved camanho stiffness reduction coefficient through the ABAQUS software. The experimental verification was carried out， and it was emphatic on the effect of combinations on the tensile static strength and damage in double-nail single-shear connections with different maintenance aperture. The results show that the load-displacement curve and failure mode obtained by the finite element analysis are basically consistent with the test results， with a maximum error of 8.9%.The bolt load of D₂ near the loading end is higher than that of the bolt D₁ near the fixed end of the metal plate. The D₂ diameter increased（W/D₂ decrease） with the standard connection parameters can improve the stress concentration at the edge of the double-bolted connection hole， and increase the initial and ultimate strength. But excessive D₂ diameter will reduce the net cross-sectional area of the composite sheet， resulting in a decrease in joint strength.The increase of the friction coefficient will prolong the occurrence of the initial damage of the composite plate， resulting in a significant delay in the attenuation of stiffness.