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Abstract:The effect of the dynamic pyrolysis of PGE/ Phenolic composites on the temperature field is studied through the establishment of transient heat conduction differential equation under dynamic pyrolysis. A comparative analysis is performed between the theoretical and the experimental results. The results show that it can amend the temperature field computational accuracy availabily, the theoretical mould are more close to the experimental ones.

Abstract:In order to solve the problem of poor precision for measuring C/ C composite elastic constant by traditional test method, the present paper provided a new method for obtaining the main elastic constants from modal test. According to the modal test data and the relationship between vibration frequencies and elastic constant, the scope of the elastic constants were estimated preliminarily. Then the quadratic response surface approximate model about elastic constants and vibration frequencies was established to optimize the elastic constants. The isotropic and orthotropic thin plates were used to verify this method. The results show that the maximum error is 16. 67%, the minimum is only 0. 5%, so the method is accurate and effective. At last, the elastic constant of needled C/ C composite is obtained through the present method. The simulation and experimental results proved that the method is nondestructive,efficient and accurate.

Abstract:A new trend-carbide ceramifiable thermal insulation is proposed, which based on the excellent performances of nano-composites, such as flame-retardant and ceramification of montmorillonite on polymers. After the adding． low-melting point organic-modification nano montmorillonite is ablated and blowed by the high temperature combustion gas, a kind of viscous liquid can be formed and it will inter-crosslink with the decomposed char layer, blocking the volatilization of the pyrolysed gas and exfoliation of the resulted char-layer, as a result, the performances such as ablation, erosion-resistance and smoke signals will be improved. The results indicate that the performances of the thermal insulation are all optimized under the condition of the ratio of nano-montmorillonite to silica is 13 ∶27, meanwhile, the smoke-signals increased 50%.

Abstract:This paper introduces using silicon resin as a ramjet engine insulation layer of matrix material, with YJ short fiber or fabric as reinforced two insulation formula ablative properties of materials. The influence of content of YJ short fibers and the mass ratio of silicone resin/ fiber fabric, on the insulation ablation rate and the process performance was studied. The results show that YJ short fiber is 4 phr, the comprehensive performance of ablation and silicon resin/ YJ short fiber/ zirconia formula was the best, and the mass ratio of silicone resin and the fabric is 1. 1 ∶1, silicone resin/ fiber fabric formulations of oxyacetylene ablation rate is the smallest, with only 15. 2 μm/ s. 20 seconds compression ratio engine ground test results show that the two formulations, insulation of ramjet engine implemented effective thermal protection.

Abstract:A low temperature-resistant and non-asbestos NBR insulation formula named TI506 was preparation by using fire retardant agent containing halogen-Sb,aramid fiber and plasticizer. The effect of content of aramid fiber on erosion perfomance of the insulation was investigated. The effect of content of plasticizer on glass transition temperature( Tg) of NBR insulation was also studied. The results showed that the optimum linearosion rate is 45 μm/ s when the content of aramid fiber pulp is 10 to 15 portions and the content of aramid fiber staple is 4 to 6 portions, and when the content of plasticizer DOS is 10 portions, DBP or ATBC is 20 portions,Tg of the NBR insulation can reach -40℃. In addition, mechanical performance, specific heat capacity and conduction coefficient were tested respectively. The results showed that mechanical and erosion perfomances of the NBR insulation by using aramid fiber are excellent,and it made solid rocket engines endure the condition with the temperature from -40℃ to 60℃.

Abstract:This paper is focused on the properties of modified domestic polyaramid fiber(F-3A) and F-3A fiber reinforced epoxy composites (F-3A/ epoxy), which is studied on the background of prepareation of F-3A fiber and application of F-3A/ epoxy composite. The composite was prepared by F-3A fiber and a kind of new epoxy resin system, the properties of unidirectional NOL ring composite and full scale composite structures were studied. The results show that the mechanical properties and process performance of F-3A fiber are excellent, the fiber can be used as high performance reinforcements in advanced composite fields.

Abstract:The work of this paper was focused on the effect of reinforcement, cure system and plasticizer on properties of vulcanized butadiene-isoprene rubber resilient material. The result showed that the resilient material had better mechanical property reinforced by the carbon black N330 or N220 than carbon black N770, according to the specific surface. With the addition of 0. 8 to 1. 3 parts sulfur, the resilient material had desirable characteristics at - 40 to +60℃. The hardness and modulus of resilient material can be adjusted by adding of plasticizer. Furthermore, the property of the resilient material and the operational performance on flexible bearing were compared,the result showed that the shear properties at -40 to +60℃ and compress properties of the resilient material could represent the swing properties and compress properties of flexible bearing.

Abstract:Aimed at the development status of solid rocket motor nozzle thermal protection materials, basalt fiber was used to produce phenolic resin composites. Mechanical property, thermal property and ablative property were tested. The micro-morphology of specimens after test are investigated by SEM. The results show that the density is less than 1.75 g/ cm3,the max compress strength in axial direction is up to 335 MPa, the thermal conductivity in axial direction and radial direction is (0.3 to 0.4)W/ (m·K). The requirements of nozzle thermal protection materials are satisfied.

Abstract:The surface characteristics of RS and MS carbon fibers were analyzed by using the scanning electron microscopy,specific surface area and pore volume test equipment. The interface properties of C/ C composite were tested by carbon push down method, bend strength and impact shear strength. The results show that the section of RS -Cf is circular and MS-Cf is kidney. The surface groove of RS-Cf fiber is clear, but obviously less than MS-Cf. The Special surface area and pore volume of MS-Cf are more than RS-Cf. The interface strength of MS-C/ C composite is higher than that of RS-C/ C composite,because the interface strength, bend strength and impact shear strength of MS -C/ C composite are 3. 80 MPa,65. 0 MPa and 35. 2 MPa respectively,being higher than RS-C/ C composite’ 2. 98 MPa, 55. 9 MPa and 32. 0 MPa.

Abstract:Quasi-three dimensional needled C/ C-silicon carbide thin-wall throats were prepared by CVI+PIP combined process. The performs were spreading individually by carbon cloth layers which is copying the inner moulding surface of the throat and 30° carbon cloth layers which is the same as the entrance angle of the throat. The effect of the two carbon cloth spreading means on the bending performance, integral bearing performance and anti-ablative and erosion properties of C/ C-SiC components are investigated. Results show that the bending intensity of the components is 205 MPa and 152 MPa and the hydraulic bursting pressure is 6. 5 MPa and 4. 9 MPa separately. The ablation properties are investigated using oxyacetylene ablation technique with the angle between the gas flow and material surface is 30°. The anti-ablative and anti-erosion properties of 30° carbon cloth spreading composites is excellent. The linear ablation rate is 70% compared to that of carbon cloth copying spreading composites after 200 s ablation time.

Abstract:C/ C composites were prepared by chemical vapor deposition. During the process integral felt and propane were used as perform and carbon source separately. Emphases were focused on temperature and residual time. The microstructure was observed by polarizing microscope, and the exhausts were detected by gas chromatograph. A commercial software COMSOL was used to study the intermediate gases and reaction path. Results indicated that the as-prepared pyrocarbon was characterized by smooth laminar structure. H2,C2H2,C2H4,CH4 were majority of the intermediate gases during deposition. Macro-molecule and H2 are increased by increasing of the temperature. C2H4 is quickly decreased by increasing of the temperature. Macro-molecules with low C-H bended energy are easy to form free radicals and the contents would first increase then decrease with increase of residual time. Contents of macro-molecules with unsaturated structures changed slowly. C2H4 played an important role during the whole deposition process.

Abstract:SiO2 / PF composite materials with HGB content of 0,3%,5%,10% respectively were prepared. The effects of HGB content on the density, thermal physical properties, ablation resistance, thermal expansion properties, mechanical properties were investigated. The results show that, HGB addtion can reduce the SiO2 / PF density, improve the heat resistance, ablation resistance and mechanical properties. When the HGB content is 5%, the system density is 1． 634 g/ cm3. At 23℃ cp increased from 1.062 to 1.137 J/ (g·K), 950℃, quality retention rate is 82． 08%. The linear ablation rate and mass ablation rate is 91 μm / s and 66． 9 μg/ s,about 35.9% and 20.1% lower than that of SiO2 / PF. The tensile strength, the bending strength and the shear strength are increased by 12.86%, 21.50% and 7． 80%.

Abstract:High temperature resistant and rent burning silicone rubber and fillers were pressed into the adhesive sheet using the molding process. The material density is 0. 56 g/ cm3,specific heat is 1. 371 J/ ( g·k), thermal conductivity is 80 mW/ (m·K),tensile strength is 1. 87 MPa,and the elongation at break is 25%. At the wind tunnel environment of high enthalpy and low heat flow of certain type solid rocket motor,interface temperature is 70. 7℃ for 1 mm thick insulation material. And the apparent of specimens is complete with no cracking.

Abstract:A bisphenol A epoxy-modified silicone rubber was prepared by the chemical grafting, and the structure of modified-silicone rubber was characterized by FTIR. The effects of catalyst and epoxy resin content on the mechanical property of modified-silicone rubber as well as its curing system were investigated. The modified-silicone rubber was used in the external thermal protection coating of the solid rocket motor, and the coating performance was assessed by the supersonic arc wind tunnel experiments. It is found that the appropriate addition of etraisopropyl titanate could improve the mechanical property of modified-silicone rubber during the preparation. In addition, the mechanical properties of silicone rubber obtained increased with the epoxy content. When the epoxy content exceeded 20wt%, the tensile strength and the bonding strength of the rubber are greater than 2 MPa and 3 MPa, respectively. RCA-polyamide 650 composite curing system can be used to cure the modified-silicone rubber. The results show that the structure of the coating sample is integrity, and the back wall temperature of the coating sample is below 152℃ after wind tunnel experiments.

Abstract:An elastic thermal insulation coating with low density and high-temperature resistance was developed for applition onto carbon fiber composite case for solid rocket motors exposed to thermal environment, which has experienced static quartz lamp radiation test and arc-heated wind tunnel test for thermal protection performance evaluation. It is observed that the said thermal insulation coating provided such properties as density of 0. 62 g/ cm3, elongation in the range of 25%, and thermal conductivity in the range of 0. 18 W/ (m·K). The DSC test results indicated that the weight loss rate is 6. 6% at 401℃. The evaluation test has shown that the said thermal insulation coating of 1. 0 mm thickness exhibited superior thermal protection performance with case-to-coating interfacial temperature up to 77. 3℃ and back case surface temperature up to 44. 5℃.

Abstract:This paper presents an innovative thermal protection coating material for solid rocket motors, that was subjected to high heat flux in a short time for arc-heated wind tunnel test. It is observed that the back surface of the coated samples with thermal protection coating can be cooled to 144℃ with a drop of 300℃ at least in comparison with that of the uncoated samples. The results showed that the back temperature of the samples with 0. 5 mm coating was little superior to that in the case of 0. 8 mm coating. Moreover, the back temperature of the coated samples cured at room temperature with a drop of 30℃ by contrast with that of the samples cured at high temperature, and the samples in both cases have the back temperature below 234℃ in accordance with the design value of less than 350℃.

Abstract:Bismaleamic was selected paper-based test system for the polyimide resin, and a matrix material was modification. The results show that: the material can be modified in the intermediate curing temperature and meet the high-temperature requirements of 360℃. Choosing a lower density sheet metal powder as a conductive filler, and using is bentonite as a composite of polyethylene wax and anti-settling agent, the modified polyimide surface resistance is down to 0. 59 Ω, shielding effectiveness is greater than 40 dB,and the material has good anti-settling properties ,impact resistance and flexibility to meet the requirements of the engine.

Abstract:Effects of insulator surface treatment, liner thickness, and the time between the lining and casting on interface bonding property had been investigated in the way that interface bonding strength was tested using K/ J/ B and K/ J/ B/ Y rectangular specimen. The results show that bonding strength between non-precure liner and non-roughened EPDM insulator is only 1. 0 MPa. In order to ensure good bonding ,the surface of EPDM insulator must be roughened and cleaned first. When liner thickness is between 0. 3 to 0. 5mm, the bonding strength does not change. But when it increace to 0. 7 mm , the bonding strength is increasing. K/ J/ B/ Y specimen test is OK, break took place inside propellant. Time from 4h to 24h of end of lining and casting has little effects on interface bonding strength. Non-precure liner has no effects on standing process procedure.

Abstract:There was a direct link between the control technology of the polymerization process and the performance of the virgin carbon fiber by using a continuous polymerization process to produce PAN fiber in the engineering production. In this way a series arrangement of three reactors in continuous polymerization process for preparing the PAN was studied. The reaction temperature was a main polymerization factor in the terpolymer system with the acrylonitrile (AN), itaconic acid (IA) and 2-Acrylic amino-2-methyl propane sulfonic acid (AS) as co-monomers between the monofilament mechanical properties of the PAN fiber. The results showed that polymerization temperature can directly affect the intrinsic viscosity and the specific viscosity of the spinning solution, which further affect the structure and properties of the fiber obtained by spinning. With the polymerization temperature decreased gradually, the specific viscosity of the spinning solution increased gradually, while the fiber strength had increased and then decreased. When the reaction temperature was low to a certain temperature, the spinning solution viscosity had increased rapidly, which resulted a deterioration of the spinning process and affected the normal engineering production.

Abstract:This paper adopts pulse TIG welding to weld the T250 maraging steel thin-walled spinning cylinder. By optimizing process parameters, weld joints with weld formation and internal defects meet the requirement of QJ175 -93 0 grade was obtained. Heat treatment was carried out to T250 maraging steel thin-walled spinning cylinder prior to weld and post weld. The influence of heat treatment on microstructure, microhardness,angular distortion and mechanical properties of weld joints was studied. The results showed that after aging treatment, reverted austenite exist in dendritic grain boundary in weld metal, microhardness is lower than basic metal. The grain near the fusion lion of welding heat affected zone grow and the largist grain size was 6 times of base metal. Heat treatment prior to weld decreased the angular distortion greatly. On the premise of 500℃ aging treatment post weld,aging treatment prior to weld improve the tensile strength and the bending angle. The best strength and toughness properties was obtained by 500℃ aging treatment prior to weld and 500℃ aging treatment post weld.

Abstract:The process of spinning tube of Ti1300 titanium alloy was investigated. The temperature on hot spinning was 800 to 900℃. The roller feedin ratio was varied, and it is 0. 5 to 0. 8mm/ r in first spinning and it is 1. 2 to 2． 0 mm/ r in end spinning. The limit thinning ratio was about 85%, and each thinning ratio was 45%. It could be realized large thinning ratio with spinning process, but the cumulative thinning ratio was not too large.

Abstract:This paper studies the hydrogen embrittlement of ultra-high-strength steel 30Si2MnCrMoVE in nitrogen and methanol nitrogen-based atmosphere heat treated with the sealing box multi-purpose furnace in heat treatment production line. The results show that the mechanical properties, fracture toughness,microstructure and fracture morphology in nitrogen-based atmosphere heat treated with H2≤3% nitrogen are the same as the ordinary heat treatment. No hydrogen embrittlement tendency has been found. Although the nitrogen-based atmosphere heat treatment improved the apparent quality,the 30Si2MnCrMoVE stil exist decarburization phenomenon.

Abstract:The complicated stress is easy to occur on the dome of T800HB/ epoxy composite case, which cause case dome failure at low pressure. Through optimizing the joint flange and dome reinforcement, the burst pressure of T800HB/ epoxy composite case increases from 28. 6 MPa to 36. 4 MPa. The fiber strength transfer rate increases from 65. 7% to 85. 6%

Abstract:By analyzing the acoustic emission detection signal of composite winding shell in the process of external load test, this paper gives damage feature signal descriptions and identifies the severely damaged parts according to the location of the acoustic emission sensors and the concentration of damage feature signal. Experiments show that Amplitude>80 dB & Duration<3 ms single is a major cause of composite winding shell in the process of external load test. Finally, general acoustic emission detection approach of composite winding shell is presented.

Abstract:End lid on spray pipe is made of short glass fiber/ barium phenolic resin, some end lids cracked after five years under naturally store. By examination,test and analysis, it is considered that the end lids cracked by the reason of that, mass ratio of resin of local part in end lid is relatively low that resulted in lower intensity. There was internal stress in the end lid at the same time and intensity of material fell gradually during naturally store, then the end lids cracked when intensity fell lower than internal stress.