Abstract:

In this paper, a parametric finite element (FE) model has been developed to allow a broad study into
the effect of various parameters on the performance of a scarf joint. The buckling load of scarf repair composite structure
has been investigated and determined with respect to changes in scarf angle, adhesive thickness and lay-up sequence.
Furthermore,the best scarf repair model was developed. Dissimilar material joint improves the stability of scarf
repair composite structure extraordinarily. The adhesive thickness varying between 0. 15 mm and 0. 25 mm,reducing
the adhesive thickness also improves the stability of scarf repair composite structure. The scarf repair model with [03/
±45/ ±45/ 90]s has the best stability. The results of this investigation provide further insight into the failure that develops
in scarf repairs of composite structures under compressive load

Abstract:An aromatic amine cured epoxy resin formulation system has been developed according to the characteristic
of the domestic aramid fiber. The curing process of the formulation system was studied by DSC test. Mechanical
property of the resin casting body was measured by universal testing machine. The interlaminar shear strength (ILSS)
of NOL-ring samples and explosion properties of Φ150 mm standard pressure vessels prepared by the domestic aramid
fiber reinforced aromatic amine cured epoxy composite were also investigated. The results indicate that the epoxy formulation
system provide excellent mechanical properties and heat-resistance performance. The tensile strength,elongation
rate at break,flexural strength and martin heat resistant temperature of the casting body are 101 MPa,4. 1%,177
MPa and 142. 2℃ respectively. The interfacial adhesion property of the composite is pretty good. The ILSS of the composite
and PV / W of Φ150 mm pressure vessels are 52. 1 MPa and 38. 44 km respectively.

Abstract:Filament winding process is used to fabricate the F-3A composite tubes,and the effect of resin formula
and reinforced fiber on axial compression property as well as the failure mode of composite tubes was studied. The
results reveal that(1)The TH-1 resin formula shows excellent compatibility for the F-3A fiber composite,(2)The axial
compressive strength of domestic F-3A fiber composite tube is higher than F-12 composite tube up to 16. 5% to
23. 9% and higher stability,(3)The failure mode of domestic F-3A fiber composite tube appears brittleness while F-
12 fiber composite tube shows toughness.

Abstract:Nanocomposites consisting of multi-walled carbon nanotubes( MWCNT) and an epoxy matrix were
produced by three roll mill. A very good dispersion of MWCNT in an epoxy resin could be observed by optimizing the
processing conditions. Compared to epoxy,the tensile and flexural strength of the as-processed nanocomposites are increased
by 22%,15%, respectively, and the electrical conductivity and thermal conductivity are significantly improved.

Abstract:The processability and heat-resistant properties of 7501 Cyanate ester were investigated. And the
EW220/7501 laminates were then produced through RTM process for evaluation of mechanical properties. The results
showed that the lowest melt viscosity of the resin is 87 mPa·s,and the processable time is more than 10 hours. After
being cured at 300℃,the Tg is 421℃ and the 5% decomposition temperature is 431℃. The mechanical properties of
EW220/7501 composites is well at room temperature, the tensile strength is 393 MPa,the compression strength is 356
MPa,the flexural strength is 602 MPa,the interlaminar shear strength is 43 MPa. And the retention rates of mechanical
properties at 300℃ is more than 80%.

Abstract:A high temperature adhesive was prepared by adding ceramic powders (SiC, ZrC, Si or Zr etc. ) to
polycarbosilane. Its rheology investigated by rheometer, The properties and relationship between component and properties
of adhesive were investigated by means of TGA, XRD and SEM. The results suggested that adhesive possessed
good high temperature resistance and adhesive intensity. The weight loss was 16wt% in 1 200℃(N2 atmosphere),and
its adhesive intensity was 6. 4 MPa.

Abstract:A high temperature adhesive was prepared by adding ceramic powders (SiC, ZrC, Si or Zr etc. ) to
polycarbosilane. Its rheology investigated by rheometer, The properties and relationship between component and properties
of adhesive were investigated by means of TGA, XRD and SEM. The results suggested that adhesive possessed
good high temperature resistance and adhesive intensity. The weight loss was 16wt% in 1 200℃(N2 atmosphere),and
its adhesive intensity was 6. 4 MPa.

Abstract:Ethylene-propylene-diene monomer ( EPDM) composites filled with polyimide fibers, polysulfonamide
fibers, and Kevlar fibers were prepared by moulding method, respectively. The thermal stability of fibers, the
ablative resistance, structures of char layers, and mechanical properties of EPDM composites, and the dispersion of
fibers within EPDM were investigated. Results indicated that polyimide fibers show a better thermal stability and higher
amount of residues than Kevlar and polysulfonamide fibers. Polyimide fibers greatly improved the ablative resistance
of EPDM composites with ablative thickness of 0. 8 mm. The mechanical properties of insulations were related with the
dispersion of fibers within rubber phase influenced by the structures of fibers.

Abstract:The PPBES/ PPENK laminate was prepared through the blend of Poly(phthalazinone biphenylene ether
sulfone) (PPBES) containing phthalazinone and poly( arylene ether nitrile) ( PPENK) with heat-resitant and
soluble by solution dipping process. The compatibility and ratio of resins were discussed. The effects of PPBES/
PPENK resin content on the flexural strength(25℃,150℃) and water absorption of the laminate were studied. The
dielectric properties and flame retardancy of the laminate were tested. The SEM result approved that PPBES and
PPENK are fully compatible. When PPBES/ PPENK =4/6 and the blending resin content is 35. 4%, the laminate
has optimum comprehensive performances. And the retention rate of flexural strength on 150℃ is 95. 7%. Under condition
of 1MHz, the dielectric constant and dielectric loss is 3. 5 and 0. 0037, respectively. The volume resistivity is
5. 9×1014 at DC 500 V. Its flame retardant property rate is UL94-V0.

Abstract:Based on damages probably caused by the process of production of 5228A/ CF3031 laminates, 5
kinds of defective samples were designed and produced, including the exceeding standard aperture(ESA), the elliptical
aperture(EA), the layering aperture(LA), the overly polishing aperture(OPA) and the layering fringe(LF),
and glue-injection method was proposed for restoration. ASTM standard is used to test the strength of tensile, compression,
inflexion, and longitudinal transverse and inter laminar shear of original, defective and repaired samples,
and then optical microscope was used for the observation. The result indicated that ESA has more negative impact on
the tensile strength, compression, inflexion of samples, and strength of these defective samples respectively decreased
by 11. 1%, 13. 8%, 14. 4%; OPA creates more harmful effects on the longitudinal transverse sheared strength, and
strength of these defective samples decreased by 25. 6%; inter laminar sheared strength is more vulnerable to the LF,
and strength of these defective samples decreased by 27. 3%. Additionally, the strength of all the five samples is improved
to a certain degree due to the application of glue-injection method. The improvement of laminates resistance to
small deformation (tensile, compression and inter laminar shear) for laminates is more significant than large deformation
(inflexion and longitudinal transverse shear).

Abstract:The compact and even surface of iridium coating was deposited on the rhenium metal by arc ion plating.
The microstructure and composition of as-deposited iridium coating were analyzed, and the oxidation resistance of
the iridium coating at different temperature was also studied. The isothermal oxidation resistance of the iridium coating
kept well up to 4 hours at 1 800℃ and up to 2 hours at 2 000℃, respectively. After 120 times of the cyclic oxidation
test at 1 950℃,the surface and cross-section of the Re/ Ir kept compactly and no peeling is detected.

Abstract:This study was undertaken to analysis the causes and morphology of Keyhole-Plasma Arc Welding
(K-PAW) solidification cracking of Maraging steel (C300) by means of optical microscopy (OM), scanning electron
microscopy (SEM) and Thermal-cale. The results indicated that although C300 has good weldability, it can also produce
solidification cracking. In our experimental condition, the dominant factor which induces solidification cracking
of high purity C300 was the strain-temperature growth rate. Improving the preheating temperature and increasing welding
heat input could reduce solidification cracking tendency. The preheating effect of heat source to the base metal
step-by-step was propitious to the arrest of solidification cracking. The solidification cracking tendency of weld metal
which has convex surface or fine equiaxed grains would be decreased.

Abstract:The high emissivity coatings with different surface roughness using iron oxide, silicon carbide and cobalt
oxide as high emissivity fillers were fabricated by controlling the spray times and the solid loading of coating slurry.
The room-temperature emissivity of the high emissivity coatings with different surface roughness was measured by
AE radiometer,and the high-temperature emissivity at 800℃ was determined according to GB/ T 7287—2008. The
images of the high emissivity coatings were characterized by scanning electronic microscopy and optical microscopy,
and the surface roughness of the high emissivity coatings was measured by scanning probe microscopy. It is found that
the room-temperature emissivity of the high emissivity coatings had a change of 0. 02 to 0. 05 in the condition of radiative
heat transfer during the surface roughness of the high emissivity coatings changing from 2. 75 μm to 225. 70 μm,
while the high-temperature emissivity of the high emissivity coatings had no change in the condition of heat conduction
during the surface roughness of the high emissivity coatings changing from 2. 75 μm to 36. 99 μm.

Abstract:The tensile properties under room temperature,and under liquid nitrogen temperature,and the distributing
of micro-hardness,and the results with digital speckle correlation method were compared between 2219 aluminum
alloy joints with single-layer welding and single-sided double-layer welding process. The comparison shows that the
tensile strength,the elongation rate and the micro-hardness of the joint with single-sided double-layer welding is obviously
better than the single-layer welding joint. This different is caused by the bigger heat input of single-layer welding
than the double in one time. The materials in the single-layer welding joint was more badly influenced by welding heat
input,and the height and figure of weld reinforcement on back side of joint is difficult to control

Abstract:2219 aluminum alloy is sensitive to the gas porosity. Variable polarity TIG arc welding technology can
independently adjust time and amplitude of positive and negative half period, therefore the VPTIG can be applied in
new launch vehicle. The tensile property of 2219 aluminum alloy VPTIG welding joint, tensile fractography analysis
and microstructure analysis are introduced in this paper. The results show that the strength factor of 2219 T62 aluminum
alloy VPTIG welding joint can reach 65%,the welding joint hybrid fracture and gas porosity of top layer more
than backing layer.

Abstract:There are many holes used for assembly in carbon fiber reinforced plastic (CFRP) parts, traditional
hole-making method is subject to various damages such as delamination and fiber pullout. In this paper, drilling and
helical milling CFRP are carried out, according to comparison of the machining quality of two hole-making method,
the reason of the machining defect is analyzed. It was found that helical milling is a feasible method in hole-making,
which has a broad applied value in the CFRP hole-making technology.

Abstract:To improve its conductivity, Ag/ Fe3O4 was prepared by electroless plating of silver on the surface of
Fe3O4, and in this way, we get composite material with excellent electromagnetic property. Before electroless plating,
Fe3O4 should be pretreated, which includes roughening, sensitization and activation. Results show that Ag was successfully
coated on the surface of Fe3O4, with a thickness of about 25 to 100 nm, and the mass weight of Ag is
54． 47%. In addition, compared with Fe3O4, the conductivity of Ag/ Fe3O4 is 347. 15 S/ cm, which has increased
nine orders of magnitude. Furthermore, the saturation magnetization of Ag/ Fe3O4 is 29. 8 emu/ g.

Abstract:The structural characteristic, preparation methods and mechanical properties and oxidation resistance
of the ternary layered ceramics called MAX phases are introduced in this paper. Methods for improving the mechanical
properties and high temperatue oxidation resistance of MAX phases are discussed. Finally, further trend for the development and applications of this kind of ceramics are proposed.