2005 Vol. 22, No. 3
2005, 22(3): 1-8.
Abstract:
Ternary Attapugite/ Polypropylene/ Polycarbonate (AT/ PP/ PC) composites containing particles withcore-shell morphology were achieved via the two-step melt blending process. Under the function of shear st ress,core-shell st ructure particles with AT as the core and PP as the shell were formed in the composites. The mechanicalproperties, morphology, and impact fracture surface of the ternary composites were studied by means of the tensiletester, impact tester, TEM, SEM, etc. The result s show that high toughness could be obtained by particles in thethree component systems with core-shell st ructure, and the tensile st rength and yield st ress for the three componentcomposite are higher than those of the PP/ PC composite as a result of the incorporation of AT. Based on the SEManalysis for impact morphology, it is considered that the interfacial voiding and the reinforcement effect of AT on thedispersed phase are the main toughening mechanisms in the ternary AT/ PP/ PC composites.
Ternary Attapugite/ Polypropylene/ Polycarbonate (AT/ PP/ PC) composites containing particles withcore-shell morphology were achieved via the two-step melt blending process. Under the function of shear st ress,core-shell st ructure particles with AT as the core and PP as the shell were formed in the composites. The mechanicalproperties, morphology, and impact fracture surface of the ternary composites were studied by means of the tensiletester, impact tester, TEM, SEM, etc. The result s show that high toughness could be obtained by particles in thethree component systems with core-shell st ructure, and the tensile st rength and yield st ress for the three componentcomposite are higher than those of the PP/ PC composite as a result of the incorporation of AT. Based on the SEManalysis for impact morphology, it is considered that the interfacial voiding and the reinforcement effect of AT on thedispersed phase are the main toughening mechanisms in the ternary AT/ PP/ PC composites.
2005, 22(3): 9-15.
Abstract:
The in-situ microfibrillar composite based on poly (ethylene terephthalate) ( PET) and polyethylene( PE) was prepared through melt ext rusion, hot stretching and quenching process. Fixing the mass composition(15 ∶85) of the PET and PE, increasing the hot stretch ratio, the spherical and ellipsoidal PET particles t ransformto rodlike particles, finally to well-defined microfibers. During hot stretching, the maximum and average diametersof PET particles reduced steadily while the minimum fiber diameter remained constant . The PET fibers were successfully preserved in the materials while being processed at the processing temperature of PE, but they were meltedagain and deformed into spherical particles at the processing temperature of PET. The tensile modulus and st rengthof the microfibrillar composites are significantly enhanced with increasing the hot st retching ratio, indicating that themicrofibers have a good reinforcement on the PET/ PE composites. The ultimate elongation is greatly decreased withhigher hot stretching ratio and there is a critical hot st retching ratio, at which the ductile-brittle t ransition occurs.The specific essential work of f racture ( we ) of the composite first increases with the increase of the hot stretch ratio,and shows a maximum at a hot st retch ratio of 19117, then decreases with further increasing the hot st retch ratio.
The in-situ microfibrillar composite based on poly (ethylene terephthalate) ( PET) and polyethylene( PE) was prepared through melt ext rusion, hot stretching and quenching process. Fixing the mass composition(15 ∶85) of the PET and PE, increasing the hot stretch ratio, the spherical and ellipsoidal PET particles t ransformto rodlike particles, finally to well-defined microfibers. During hot stretching, the maximum and average diametersof PET particles reduced steadily while the minimum fiber diameter remained constant . The PET fibers were successfully preserved in the materials while being processed at the processing temperature of PE, but they were meltedagain and deformed into spherical particles at the processing temperature of PET. The tensile modulus and st rengthof the microfibrillar composites are significantly enhanced with increasing the hot st retching ratio, indicating that themicrofibers have a good reinforcement on the PET/ PE composites. The ultimate elongation is greatly decreased withhigher hot stretching ratio and there is a critical hot st retching ratio, at which the ductile-brittle t ransition occurs.The specific essential work of f racture ( we ) of the composite first increases with the increase of the hot stretch ratio,and shows a maximum at a hot st retch ratio of 19117, then decreases with further increasing the hot st retch ratio.
2005, 22(3): 16-20.
Abstract:
The statistical st rength and dist ribution of 5 cm PBO single fiber t reated with six different chemicalmediums were researched based on Weibull/ weakest-link model. The results were compared with the unt reated PBOfiber, and the surface of the fiber was analyzed by SEM. The results show that acidic mediums have more effects onthe strength and dist ribution of PBO fiber, and the break mechanisms are different between t reatment s by HCl andby H2SO4 .
The statistical st rength and dist ribution of 5 cm PBO single fiber t reated with six different chemicalmediums were researched based on Weibull/ weakest-link model. The results were compared with the unt reated PBOfiber, and the surface of the fiber was analyzed by SEM. The results show that acidic mediums have more effects onthe strength and dist ribution of PBO fiber, and the break mechanisms are different between t reatment s by HCl andby H2SO4 .
2005, 22(3): 21-24.
Abstract:
The transverse impact test of AF/ ZF (Aramid Fiber/ Zylon Fiber) hybrid composite was performed bySHPB (Split Hopkinson Pressure Bar) . The loading history and displacement history of the composites with different hybrid ratios were obtained, f rom which the failure process and energy absorption characteristics were furtheranalyzed. The change t rends of BPI (Ballistic Performance Indicator) data obtained f rom SHPB are similar to thoseof the ball firing data, indicating that the transverse impact test on AF/ ZF hybrid composite has a certain referencevalue to predict the energy absorption of composites target in the ball firing.
The transverse impact test of AF/ ZF (Aramid Fiber/ Zylon Fiber) hybrid composite was performed bySHPB (Split Hopkinson Pressure Bar) . The loading history and displacement history of the composites with different hybrid ratios were obtained, f rom which the failure process and energy absorption characteristics were furtheranalyzed. The change t rends of BPI (Ballistic Performance Indicator) data obtained f rom SHPB are similar to thoseof the ball firing data, indicating that the transverse impact test on AF/ ZF hybrid composite has a certain referencevalue to predict the energy absorption of composites target in the ball firing.
2005, 22(3): 25-29.
Abstract:
The mechanical properties and morphology of nano-CaCO3 / SBS or mSBS / PS composites were studied.In a nano-CaCO3 / mSBS/ PS system, nano-CaCO3 particles are mostly encap sulated in mSBS. The core-shell st ructure increases the volume f raction of elastomer (mSBS) and enlarges the effect of mSBS on the mechanical propertiesof this system. On the other hand, the concent ration of nano-CaCO3 particles decreases in PS mat rix, which prevent s nano-CaCO3 (especially agglomerated nano-CaCO3 particles) f rom impairing the mechanical properties of thesystem. Compared with SBS system, the costs of the composites decrease with the increase of optimum loading ofnano-CaCO3 .
The mechanical properties and morphology of nano-CaCO3 / SBS or mSBS / PS composites were studied.In a nano-CaCO3 / mSBS/ PS system, nano-CaCO3 particles are mostly encap sulated in mSBS. The core-shell st ructure increases the volume f raction of elastomer (mSBS) and enlarges the effect of mSBS on the mechanical propertiesof this system. On the other hand, the concent ration of nano-CaCO3 particles decreases in PS mat rix, which prevent s nano-CaCO3 (especially agglomerated nano-CaCO3 particles) f rom impairing the mechanical properties of thesystem. Compared with SBS system, the costs of the composites decrease with the increase of optimum loading ofnano-CaCO3 .
2005, 22(3): 30-34.
Abstract:
Core-shell st ructured acrylate impact modifier (AIM) particles of poly ( butyl acrylate) graf ted poly(methyl methacrylate) ( PBA-g-PMMA) were synthesized, which were used to prepare AIM/ PVC blends by melting process. AIM particles dist ribution and it s cavitations in PVC resin, the f racture and brittle-ductile t ransition ofAIM/ PVC blends were investigated. The result s show that spherical AIM particles well disperse in the PVC mat rixand toughen the PVC resin effectively. The impact test samples with 615 % (mass f raction) AIM modifiers broke inductile failure. It was found that cavitations are formed in the st ress-whitened area near the fracture surface. Thetoughening mechanism of PVC is synergistic toughening by cavitations of the rubber particles and shear yielding ofthe mat rix.
Core-shell st ructured acrylate impact modifier (AIM) particles of poly ( butyl acrylate) graf ted poly(methyl methacrylate) ( PBA-g-PMMA) were synthesized, which were used to prepare AIM/ PVC blends by melting process. AIM particles dist ribution and it s cavitations in PVC resin, the f racture and brittle-ductile t ransition ofAIM/ PVC blends were investigated. The result s show that spherical AIM particles well disperse in the PVC mat rixand toughen the PVC resin effectively. The impact test samples with 615 % (mass f raction) AIM modifiers broke inductile failure. It was found that cavitations are formed in the st ress-whitened area near the fracture surface. Thetoughening mechanism of PVC is synergistic toughening by cavitations of the rubber particles and shear yielding ofthe mat rix.
2005, 22(3): 35-39.
Abstract:
In order to understand how the environmental factors affect the internal st ructure of the carbon fiberreinforced epoxy resin composites (CFRERC), the relationship between the elect rochemical parameters and the corrosive extent of the composites was investigated by means of the elect rochemical impedance spect roscopy ( EIS) andcyclic voltammograms (CV) curves. The test result s show that the fiber it self does not react with the environment .The ions penet rate into composites and the ions concent ration increases with the immersion time, which leads to thefailure of the composites. The result s indicate that the concent ration and the penet ration process of the ions in thecarbon fiber reinforced epoxy resin composites can be detected by the elect rochemical method.
In order to understand how the environmental factors affect the internal st ructure of the carbon fiberreinforced epoxy resin composites (CFRERC), the relationship between the elect rochemical parameters and the corrosive extent of the composites was investigated by means of the elect rochemical impedance spect roscopy ( EIS) andcyclic voltammograms (CV) curves. The test result s show that the fiber it self does not react with the environment .The ions penet rate into composites and the ions concent ration increases with the immersion time, which leads to thefailure of the composites. The result s indicate that the concent ration and the penet ration process of the ions in thecarbon fiber reinforced epoxy resin composites can be detected by the elect rochemical method.
2005, 22(3): 40-44.
Abstract:
A new epoxy composite system was developed, being suitable for the case of inner pressure vesselswith PE as inner liner for water t reatment with wet fiber-inding. The examinations of viscosity, mechanical properties and blast were done. The results show that the modified epoxy composite system has longer gel time andlower viscosity at room temperature, and it can gel and cure at lower temperature. So the composite vessel has goodmechanical properties and fatigue property, higher blast st rength and lower cost, being capable of water t reatmentwith wet fiber-winding.
A new epoxy composite system was developed, being suitable for the case of inner pressure vesselswith PE as inner liner for water t reatment with wet fiber-inding. The examinations of viscosity, mechanical properties and blast were done. The results show that the modified epoxy composite system has longer gel time andlower viscosity at room temperature, and it can gel and cure at lower temperature. So the composite vessel has goodmechanical properties and fatigue property, higher blast st rength and lower cost, being capable of water t reatmentwith wet fiber-winding.
2005, 22(3): 45-48.
Abstract:
Polypyrrole/ carbon black conducting composites were prepared by chemical polymerization adsorbedpolypyrrole onto conducting carbon black. The constitution, st ructure and performances of the composites werestudied and characterized by FT-IR, TGA, SEM, four-probe and elect rochemical test measurement s. The int roduction of conducting carbon black not only increases the conductivity f rom 6.52 S/ cm to 13.42 S/ cm but also improvesthe bulk density, particle morphology and the film molding property of the composites. Consequently the performances of Li/ PPy secondary battery are enhanced when the composites are employed as positive elect rode materials. Itwas found that the initial specific discharge capacity of the battery reaches 41 mAh/ g calculated by PPy, and the discharge capacity shows a slight decrease and the coulombic efficiency is still over 98 % af ter 30 charge-discharge cyclesat room temperature.
Polypyrrole/ carbon black conducting composites were prepared by chemical polymerization adsorbedpolypyrrole onto conducting carbon black. The constitution, st ructure and performances of the composites werestudied and characterized by FT-IR, TGA, SEM, four-probe and elect rochemical test measurement s. The int roduction of conducting carbon black not only increases the conductivity f rom 6.52 S/ cm to 13.42 S/ cm but also improvesthe bulk density, particle morphology and the film molding property of the composites. Consequently the performances of Li/ PPy secondary battery are enhanced when the composites are employed as positive elect rode materials. Itwas found that the initial specific discharge capacity of the battery reaches 41 mAh/ g calculated by PPy, and the discharge capacity shows a slight decrease and the coulombic efficiency is still over 98 % af ter 30 charge-discharge cyclesat room temperature.
2005, 22(3): 49-54.
Abstract:
The surface of PAN-based carbon fibers was modified by elect rochemical oxidation. The surface state ofmodified carbon fibers was studied using SEM, AFM, XPS and XRD. The relationship s of surface state of carbonfibers and it s tensile st rength and mechanical performance of carbon fiber reinforced PAN (CFRP) were discussed.The result s show that surface roughness of modified carbon fibers was 1.1 times higher than that of the unt reatedone. Carbon content s decrease by 9.7 %, oxygen and nit rogen content s increase by 53.8 % and 7.5 times respectively, and the hydroxyl and carbonyl content s also increase. The surface orientation index reduces by 1.5 %, and themicrocrystalline dimension also decreases, and the active carbon atoms of carbon fiber surface increase by 78 %. Thetensile st rength of carbon fibers decreases by 8.1 % due to corrosion process of the elect rochemical oxidative method. The physical and chemical properties of carbon fiber, surface are modified during this process, the cohesivenessbetween the fibers and resin mat rix is improved and the ILSS of CFRP is increased by 26 %.
The surface of PAN-based carbon fibers was modified by elect rochemical oxidation. The surface state ofmodified carbon fibers was studied using SEM, AFM, XPS and XRD. The relationship s of surface state of carbonfibers and it s tensile st rength and mechanical performance of carbon fiber reinforced PAN (CFRP) were discussed.The result s show that surface roughness of modified carbon fibers was 1.1 times higher than that of the unt reatedone. Carbon content s decrease by 9.7 %, oxygen and nit rogen content s increase by 53.8 % and 7.5 times respectively, and the hydroxyl and carbonyl content s also increase. The surface orientation index reduces by 1.5 %, and themicrocrystalline dimension also decreases, and the active carbon atoms of carbon fiber surface increase by 78 %. Thetensile st rength of carbon fibers decreases by 8.1 % due to corrosion process of the elect rochemical oxidative method. The physical and chemical properties of carbon fiber, surface are modified during this process, the cohesivenessbetween the fibers and resin mat rix is improved and the ILSS of CFRP is increased by 26 %.
2005, 22(3): 55-59.
Abstract:
In order to determine the proper heat t reatment temperature for C/ C composites with different fibrevolume f ractions, C/ C composites were made by needled felt with fibre volume f raction of 40 %, 30 % and 25 % densifying through three times of CVI. The graphitization degree of C/ C composites without heat t reatment and withheat t reatment at 2200 ℃and 2400 ℃was investigated by means of X-ray diff raction and Raman spectra. The resultsshow that the microst ructures of three kinds of C/ C composites are smooth laminar (SL), and C/ C composites withhigher fibre volume f raction have higher graphitization degree ; the st ress graphitization takes place at the interfacebetween fibre and smooth laminar pyrolytic carbon and different smooth laminar pyrolytic carbons and the former islarger than the later, which is the reason why C/ C composites with higher fiber volume f raction have higher graphi2tization degree. The higher the heat t reatment temperature ( HTT), the higher the st ress graphitization degree.
In order to determine the proper heat t reatment temperature for C/ C composites with different fibrevolume f ractions, C/ C composites were made by needled felt with fibre volume f raction of 40 %, 30 % and 25 % densifying through three times of CVI. The graphitization degree of C/ C composites without heat t reatment and withheat t reatment at 2200 ℃and 2400 ℃was investigated by means of X-ray diff raction and Raman spectra. The resultsshow that the microst ructures of three kinds of C/ C composites are smooth laminar (SL), and C/ C composites withhigher fibre volume f raction have higher graphitization degree ; the st ress graphitization takes place at the interfacebetween fibre and smooth laminar pyrolytic carbon and different smooth laminar pyrolytic carbons and the former islarger than the later, which is the reason why C/ C composites with higher fiber volume f raction have higher graphi2tization degree. The higher the heat t reatment temperature ( HTT), the higher the st ress graphitization degree.
2005, 22(3): 60-63.
Abstract:
CVD-SiC coated C/ SiC composites were implanted with boron ions by plasma source ion implantation toimprove it s oxidation resistance. Depth profile of the boron ions in the boron-implanted SiC-C/ SiC composites waschecked by Auger elect ronic energy spect rum. Oxidation test s of the SiC-C/ SiC composites were performed in flowing dry air at 1300 ℃. The sample with boron ion implantation exhibit s lower mass loss than those without boron ionimplantation. The surface morphology of the sample was obtained by scan elect ronic microscope. Some air bubbleswere observed in the coating. Flexural st rength test s show that the mechanical property of ion-implanted sampleschanges little compared with that of the samples without ion implantation.
CVD-SiC coated C/ SiC composites were implanted with boron ions by plasma source ion implantation toimprove it s oxidation resistance. Depth profile of the boron ions in the boron-implanted SiC-C/ SiC composites waschecked by Auger elect ronic energy spect rum. Oxidation test s of the SiC-C/ SiC composites were performed in flowing dry air at 1300 ℃. The sample with boron ion implantation exhibit s lower mass loss than those without boron ionimplantation. The surface morphology of the sample was obtained by scan elect ronic microscope. Some air bubbleswere observed in the coating. Flexural st rength test s show that the mechanical property of ion-implanted sampleschanges little compared with that of the samples without ion implantation.
2005, 22(3): 64-69.
Abstract:
Al2O3 / 3Y-TZP laminated composite was fabricated using the tape casting and hot-press sintering. Themicrost ructure was observed by SEM. The as-received material was deep-drawn at high temperatures to research it ssuperplasticity. The result s show that the microst ructure of the material sintered at 1550 ℃has fine grain and st ronginterfaces. When the st rain rate is constant, the forming temperature has great influence on the superplasticity ofAl2O3 / 3Y-TZP laminated composite. The greatest deformation height of deep-drawing was obtained at 1500 ℃. Itis worse at higher or lower forming temperatures.
Al2O3 / 3Y-TZP laminated composite was fabricated using the tape casting and hot-press sintering. Themicrost ructure was observed by SEM. The as-received material was deep-drawn at high temperatures to research it ssuperplasticity. The result s show that the microst ructure of the material sintered at 1550 ℃has fine grain and st ronginterfaces. When the st rain rate is constant, the forming temperature has great influence on the superplasticity ofAl2O3 / 3Y-TZP laminated composite. The greatest deformation height of deep-drawing was obtained at 1500 ℃. Itis worse at higher or lower forming temperatures.
2005, 22(3): 70-74.
Abstract:
The polyaniline microtubules were prepared by using an in-si tu doping method. The polyaniline microtubules with the dielect ric loss properties were composed with the carbonyl iron with the magnetic loss properties.The elect romagnetic properties of the composite were studied. The results show that the elect romagnetic parametercan be adjusted through changing the mass ratio of carbonyl iron to polyaniline microtubules in the composites whenthe mass ratio of paraffin wax to the composites of carbonyl iron/ polyaniline microtubules is constant at 1 ∶1.
The polyaniline microtubules were prepared by using an in-si tu doping method. The polyaniline microtubules with the dielect ric loss properties were composed with the carbonyl iron with the magnetic loss properties.The elect romagnetic properties of the composite were studied. The results show that the elect romagnetic parametercan be adjusted through changing the mass ratio of carbonyl iron to polyaniline microtubules in the composites whenthe mass ratio of paraffin wax to the composites of carbonyl iron/ polyaniline microtubules is constant at 1 ∶1.
2005, 22(3): 75-79.
Abstract:
The ordered mesoporous powders of TiO2 with tet ragonal st ructure were prepared by an organic surfaceactive agent, solvent thermal synthesis and supercritical flux drying techniques, then the CeO2 was stuffed into themesopores of TiO2 powders by an int rusive precipitation method. The ordered mesoporous st ructure of CeO2 / TiO2composites was characterized by use of TEM, HREM, BET, etc. The formation mechanisms of the mesoporousst ructure of TiO2 and the st ructure of nano-CeO2 atomic group were investigated. The result s show that the CeO2 /TiO2 system has achieved the homogeneous composite st ructure in nano-size.
The ordered mesoporous powders of TiO2 with tet ragonal st ructure were prepared by an organic surfaceactive agent, solvent thermal synthesis and supercritical flux drying techniques, then the CeO2 was stuffed into themesopores of TiO2 powders by an int rusive precipitation method. The ordered mesoporous st ructure of CeO2 / TiO2composites was characterized by use of TEM, HREM, BET, etc. The formation mechanisms of the mesoporousst ructure of TiO2 and the st ructure of nano-CeO2 atomic group were investigated. The result s show that the CeO2 /TiO2 system has achieved the homogeneous composite st ructure in nano-size.
2005, 22(3): 80-84.
Abstract:
Ti-Fe-C composite powders for Reactive Flame Spray (RFS) were prepared by precursor carbonizationcomposition process using ferrotitanium and asphalt as raw materials. TiC/ Fe composite coatings were synthesizedand deposited by RFS. The influence of C/ Ti atomic ratio on the component, microst ructure and hardness of thecomposite coatings was investigated. The result s show that C/ Ti atomic ratio has st rong influence on the component, microst ructure and hardness of TiC/ Fe composite coating. The TiC aggregate size and porosity of TiC/ Fecomposite coating increase with the increase of the C/ Ti atomic ratio.
Ti-Fe-C composite powders for Reactive Flame Spray (RFS) were prepared by precursor carbonizationcomposition process using ferrotitanium and asphalt as raw materials. TiC/ Fe composite coatings were synthesizedand deposited by RFS. The influence of C/ Ti atomic ratio on the component, microst ructure and hardness of thecomposite coatings was investigated. The result s show that C/ Ti atomic ratio has st rong influence on the component, microst ructure and hardness of TiC/ Fe composite coating. The TiC aggregate size and porosity of TiC/ Fecomposite coating increase with the increase of the C/ Ti atomic ratio.
2005, 22(3): 85-91.
Abstract:
Four kinds of WC, ZrO2, Cr2O3 and Al2O3 ceramic particles/ nickel alloy composite coatings were prepared with the plasma spraying method. The X-ray diff raction analysis was used to investigate the phase constituentof ceramic particles in composite coatings. The hardness of the ceramic particles/ nickel alloy composite coating wasmeasured by the Leeb hardness tester. The properties of bend breaking of composite coatings were measured usingCSS-1110 elect ric all-purpose test meter. The micro-st ructures of composite coatings were t reated as a binarizationaf ter morphological processing. The f ractal dimensions of the ceramic particles/ nickel alloy composite coatings withdifferent volume f ractions of particles were obtained by means of the Sandbox method. Experimental result s indicatethat the dist ributions of ceramic particles in metal mat rix have a f ractal characteristic. The f ractal dimensions increase with the increase of particle volume f ractions. The dimensions are irrelative with the kinds of ceramic particles. The hardness and dimension of composite coatings increase with the decrease of diameter of ceramic particles.The bending f racture angles decrease with the increase of dimensions of ceramic particles/ nickel alloy compositecoatings.
Four kinds of WC, ZrO2, Cr2O3 and Al2O3 ceramic particles/ nickel alloy composite coatings were prepared with the plasma spraying method. The X-ray diff raction analysis was used to investigate the phase constituentof ceramic particles in composite coatings. The hardness of the ceramic particles/ nickel alloy composite coating wasmeasured by the Leeb hardness tester. The properties of bend breaking of composite coatings were measured usingCSS-1110 elect ric all-purpose test meter. The micro-st ructures of composite coatings were t reated as a binarizationaf ter morphological processing. The f ractal dimensions of the ceramic particles/ nickel alloy composite coatings withdifferent volume f ractions of particles were obtained by means of the Sandbox method. Experimental result s indicatethat the dist ributions of ceramic particles in metal mat rix have a f ractal characteristic. The f ractal dimensions increase with the increase of particle volume f ractions. The dimensions are irrelative with the kinds of ceramic particles. The hardness and dimension of composite coatings increase with the decrease of diameter of ceramic particles.The bending f racture angles decrease with the increase of dimensions of ceramic particles/ nickel alloy compositecoatings.
2005, 22(3): 92-97.
Abstract:
The process of the elect rolytic codeposition of nickel-graphite in nickel sulfamate solution was investigated. The result s show that the plating variables have different influence on the volume f raction of graphite particlesin elect rodeposited composites. The volume f raction of graphite incorporated in deposit increases with increasingconcent ration of suspended particles in solution, and then remains constant . There are maximums related to the current density and flow velocity, while temperature and p H values exert an adverse effect . Guglielmi’s model can beused at low current densities for the composite elect roforming system. The microhardness and friction coefficient ofNi-graphite composites decrease with increasing particle concent ration in solution. The wear mass loss also decreases, but it increases at the graphite concent ration of 30 g/ L.
The process of the elect rolytic codeposition of nickel-graphite in nickel sulfamate solution was investigated. The result s show that the plating variables have different influence on the volume f raction of graphite particlesin elect rodeposited composites. The volume f raction of graphite incorporated in deposit increases with increasingconcent ration of suspended particles in solution, and then remains constant . There are maximums related to the current density and flow velocity, while temperature and p H values exert an adverse effect . Guglielmi’s model can beused at low current densities for the composite elect roforming system. The microhardness and friction coefficient ofNi-graphite composites decrease with increasing particle concent ration in solution. The wear mass loss also decreases, but it increases at the graphite concent ration of 30 g/ L.
2005, 22(3): 98-102.
Abstract:
In-situ synthesized TiB2 / Ni metal-ceramic composite coatings with different compositions were fabricated on the medium carbon steel using laser cladding. The cracking behavior in different coatings was studied bymicroanalysis. The result s show that the cracks formed in the coating with high content of ceramic phases are mainlythe following : the t ranscrystalline cracks in the bonding metal mat rix, the high density cracks at the edge of thecoating, micro-cracks on the interface of the mat rix and the hard ceramic phases and in the vicinity of the bondinginterface in the heat-affected zone, etc. The cracks in the coating are mainly caused by the thermal st ress induced bythe difference of the thermal expansion coefficient s of the coating materials and the metal mat rix, and the t ransformation st ress plays an important role too. The good quality coating can be obtained by optimal laser parametersand coating compositions.
In-situ synthesized TiB2 / Ni metal-ceramic composite coatings with different compositions were fabricated on the medium carbon steel using laser cladding. The cracking behavior in different coatings was studied bymicroanalysis. The result s show that the cracks formed in the coating with high content of ceramic phases are mainlythe following : the t ranscrystalline cracks in the bonding metal mat rix, the high density cracks at the edge of thecoating, micro-cracks on the interface of the mat rix and the hard ceramic phases and in the vicinity of the bondinginterface in the heat-affected zone, etc. The cracks in the coating are mainly caused by the thermal st ress induced bythe difference of the thermal expansion coefficient s of the coating materials and the metal mat rix, and the t ransformation st ress plays an important role too. The good quality coating can be obtained by optimal laser parametersand coating compositions.
2005, 22(3): 103-108.
Abstract:
High temperature compressive deformation of SiCW/ AZ91 composite and unreinforced AZ91 magnesiumalloy was performed using Gleeble-1500 thermal simulator in the range of deformation temperature f rom 423 to723 K, st rain rate f rom 0.002 to 0.25 s -1 and maximum deformation st rain of 60 %. The compressive t rue st resst rue st rain curves were measured and hot deformation microst ructures were observed. St rain sof tening behavior ofcomposite is more obvious than that of unreinforced alloy because of the rotation and breakage of whiskers duringcompression. The st rain rate sensitivity exponent ( m) and apparent activation energy (Q) of both the SiCW/ AZ91composite and AZ91 alloy increase with the increasing of temperature. The higher m value of the composite is considered to be resulted f rom the fine microst ructure due to the addition of SiC whiskers. The addition of whisker limit s the cross slip of dislocations and migration of grain boundary, which causes Q value of the composite higher thanthat of the unreinforced alloy. During the compression, dynamic recovery and dynamic recrystallization occur in boththe unreinforced alloy and SiCW/ AZ91 composite.
High temperature compressive deformation of SiCW/ AZ91 composite and unreinforced AZ91 magnesiumalloy was performed using Gleeble-1500 thermal simulator in the range of deformation temperature f rom 423 to723 K, st rain rate f rom 0.002 to 0.25 s -1 and maximum deformation st rain of 60 %. The compressive t rue st resst rue st rain curves were measured and hot deformation microst ructures were observed. St rain sof tening behavior ofcomposite is more obvious than that of unreinforced alloy because of the rotation and breakage of whiskers duringcompression. The st rain rate sensitivity exponent ( m) and apparent activation energy (Q) of both the SiCW/ AZ91composite and AZ91 alloy increase with the increasing of temperature. The higher m value of the composite is considered to be resulted f rom the fine microst ructure due to the addition of SiC whiskers. The addition of whisker limit s the cross slip of dislocations and migration of grain boundary, which causes Q value of the composite higher thanthat of the unreinforced alloy. During the compression, dynamic recovery and dynamic recrystallization occur in boththe unreinforced alloy and SiCW/ AZ91 composite.
2005, 22(3): 109-115.
Abstract:
In situ three-layer surface composites of Zn-27Al-9.8Mg-5.2Si and Zn-27Al-6.3Mg-3.7Si alloys wereobtained by using preheated metal mould cent rifugal casting1 The surface composites possess the microst ructureaccumulating lot s of blocky primary Mg2Si and a small amount of blocky primary Si in the inner layer, accumulatingprimary Mg2Si and primary Si in the outer layer, and without primary Mg2Si and primary Si in the middle layer1 Butonly single layer material without primary Mg2Si and primary Si was obtained in cent rifugally cast Zn-27Al-3.2Mg-1.8Si alloy. Microst ructures of cent rifugally cast Zn-27Al-Mg2Si alloys were investigated, The hardness, wearability and f racture mode of the composites were also analysed, The result s show that the hardness and wear resistanceof the composites depend mainly on the dist ribution of the primary Mg2Si and primary Si along the radial direction1The inner layer of the composite shows the highest hardness and best wear resistance1 The f racture mode of thecomposite is primarily brittle1 The middle layer of the composite exhibit s more deformation than the inner layer during the f racture1
In situ three-layer surface composites of Zn-27Al-9.8Mg-5.2Si and Zn-27Al-6.3Mg-3.7Si alloys wereobtained by using preheated metal mould cent rifugal casting1 The surface composites possess the microst ructureaccumulating lot s of blocky primary Mg2Si and a small amount of blocky primary Si in the inner layer, accumulatingprimary Mg2Si and primary Si in the outer layer, and without primary Mg2Si and primary Si in the middle layer1 Butonly single layer material without primary Mg2Si and primary Si was obtained in cent rifugally cast Zn-27Al-3.2Mg-1.8Si alloy. Microst ructures of cent rifugally cast Zn-27Al-Mg2Si alloys were investigated, The hardness, wearability and f racture mode of the composites were also analysed, The result s show that the hardness and wear resistanceof the composites depend mainly on the dist ribution of the primary Mg2Si and primary Si along the radial direction1The inner layer of the composite shows the highest hardness and best wear resistance1 The f racture mode of thecomposite is primarily brittle1 The middle layer of the composite exhibit s more deformation than the inner layer during the f racture1
2005, 22(3): 116-120.
Abstract:
Af ter being irradiated by a continuous wave Nd-YAG laser in N2 environment, the Ti powders preplaced on the surface of NiTi subst rate t ransformed into a TiN reinforced metal mat rix composite (MMC) coating. Acompact laser modified surface coating reinforced with fine TiN can be achieved with optimum process parameters.The amount of TiN reinforcement gradually decreases across the coating. SEM and EDAX result s indicate that thereis a good metallurgical bonding between the hard MMC modified layer and the NiTi alloy subst rate. The mass f raction of Ni in the modified surface coating is very low. Microhardness and wear test result s show that the surfacehardness and wear resistance are significantly enhanced. Laser surface modification can effectively improve the surface composition and performance of NiTi alloy as an implant biomedical material.
Af ter being irradiated by a continuous wave Nd-YAG laser in N2 environment, the Ti powders preplaced on the surface of NiTi subst rate t ransformed into a TiN reinforced metal mat rix composite (MMC) coating. Acompact laser modified surface coating reinforced with fine TiN can be achieved with optimum process parameters.The amount of TiN reinforcement gradually decreases across the coating. SEM and EDAX result s indicate that thereis a good metallurgical bonding between the hard MMC modified layer and the NiTi alloy subst rate. The mass f raction of Ni in the modified surface coating is very low. Microhardness and wear test result s show that the surfacehardness and wear resistance are significantly enhanced. Laser surface modification can effectively improve the surface composition and performance of NiTi alloy as an implant biomedical material.
2005, 22(3): 121-125.
Abstract:
St ructure, st rength and elect rical conductivity of Cu-11.5 %Fe in si tu composite obtained by cold drawing or cold drawing combined with intermediate heat treatments were investigated. The structures of the compositeswere examined by SEM and TEM. The result s indicate that the Fe dendrites were drawn into fine ribbons and the Feribbons are curl and fold in cross-section at st rainη ≥5.37. The fine ribbons are finer and more uniform with thest rain increasing. The experimental result s show that the tensile st rength and elect rical resistivity increase with theincreasing of deformation st rain. Af ter intermediate heat t reatment s, the st rength remains, but the elect rical resistivity decreases drastically. The elect rical resistivity of the in si tu composite with different st rains can decrease about4.4μΩ·cm af ter a series of intermediate heat t reatment s. The good combinations of the elect rical conductivity andthe tensile st rength are the following : 70.6 % IACS ( International Annealed Copper Standard) / 659 MPa (Φ 0.8),64.6 % IACS/ 752 MPa (Φ0.5) and 51.9 % IACS/ 880 MPa (Φ0.2) .
St ructure, st rength and elect rical conductivity of Cu-11.5 %Fe in si tu composite obtained by cold drawing or cold drawing combined with intermediate heat treatments were investigated. The structures of the compositeswere examined by SEM and TEM. The result s indicate that the Fe dendrites were drawn into fine ribbons and the Feribbons are curl and fold in cross-section at st rainη ≥5.37. The fine ribbons are finer and more uniform with thest rain increasing. The experimental result s show that the tensile st rength and elect rical resistivity increase with theincreasing of deformation st rain. Af ter intermediate heat t reatment s, the st rength remains, but the elect rical resistivity decreases drastically. The elect rical resistivity of the in si tu composite with different st rains can decrease about4.4μΩ·cm af ter a series of intermediate heat t reatment s. The good combinations of the elect rical conductivity andthe tensile st rength are the following : 70.6 % IACS ( International Annealed Copper Standard) / 659 MPa (Φ 0.8),64.6 % IACS/ 752 MPa (Φ0.5) and 51.9 % IACS/ 880 MPa (Φ0.2) .
2005, 22(3): 126-129.
Abstract:
When the cenosphere fly ash content is lower, the melt is easily delaminated during preparing the cenosphere fly ash reinforced aluminium composites by stir casting technology. In order to realize the distribution of cenosphere fly ash in the aluminium melt, the different part s of the sample were analyzed by SEM. The result s indicatethat there is a pure aluminium layer in the bottom of the sample, but the cenosphere fly ash dist ributes evenly in thetop of the aluminium melt . The velocity of the cenosphere fly ash moving to the top of the melt was determined bythe difference of density between cenosphere fly ash and aluminium, diameter and volume f raction of particles, aswell as viscosity of the aluminium melt . To reduce the pure aluminium layer, the viscosity of the aluminium meltshould be increased or the time of casting process should be reduced for the certain material. The down castingmethod and quick chiller are employed, so that the cenosphere fly ash has no enough time to move upward and solidify in the aluminium melt, and the cenosphere fly ash dist ributes evenly in the aluminium melt .
When the cenosphere fly ash content is lower, the melt is easily delaminated during preparing the cenosphere fly ash reinforced aluminium composites by stir casting technology. In order to realize the distribution of cenosphere fly ash in the aluminium melt, the different part s of the sample were analyzed by SEM. The result s indicatethat there is a pure aluminium layer in the bottom of the sample, but the cenosphere fly ash dist ributes evenly in thetop of the aluminium melt . The velocity of the cenosphere fly ash moving to the top of the melt was determined bythe difference of density between cenosphere fly ash and aluminium, diameter and volume f raction of particles, aswell as viscosity of the aluminium melt . To reduce the pure aluminium layer, the viscosity of the aluminium meltshould be increased or the time of casting process should be reduced for the certain material. The down castingmethod and quick chiller are employed, so that the cenosphere fly ash has no enough time to move upward and solidify in the aluminium melt, and the cenosphere fly ash dist ributes evenly in the aluminium melt .
2005, 22(3): 130-134.
Abstract:
The f racture behaviors and f ractographic features of WC/ NiCrMo steel mat rix composites under 12kinds of conditions, af ter austenization between 960 ～ 1040 ℃ then quenching and tempering, were investigatedusing single edge notched beam ( SENB) method, SEM and elect ron theory analysis. The result s show that thematerial has high st rength (σbb ～2200 MPa, σbc ～3000 MPa) and hardness ( HRC 62～68), and higher fracturetoughness (～30 MPa ·m1/2 ) . The main fractographic appearances are WC cleavage, quasi-cleavage of mat rix, dispersed dimples and dimple bands. The numerous hard phases of WC (～40 %) play a dominant role in f racture toughness and fracture behavior, and based on the alloy elect ron theory, both of the containing carbon st ructure unit swith high bond st rength andα-Fe (Ni) st ructure unit s with more lattice elect ron in mat rix cont ribute to the st rongtough support to the hard phases and lead to micro-ductility during fracture.
The f racture behaviors and f ractographic features of WC/ NiCrMo steel mat rix composites under 12kinds of conditions, af ter austenization between 960 ～ 1040 ℃ then quenching and tempering, were investigatedusing single edge notched beam ( SENB) method, SEM and elect ron theory analysis. The result s show that thematerial has high st rength (σbb ～2200 MPa, σbc ～3000 MPa) and hardness ( HRC 62～68), and higher fracturetoughness (～30 MPa ·m1/2 ) . The main fractographic appearances are WC cleavage, quasi-cleavage of mat rix, dispersed dimples and dimple bands. The numerous hard phases of WC (～40 %) play a dominant role in f racture toughness and fracture behavior, and based on the alloy elect ron theory, both of the containing carbon st ructure unit swith high bond st rength andα-Fe (Ni) st ructure unit s with more lattice elect ron in mat rix cont ribute to the st rongtough support to the hard phases and lead to micro-ductility during fracture.
2005, 22(3): 135-139.
Abstract:
The filling process of RTM for the two step 3D braid shell preform with a varying section was investigated theoretically by employing a calculating method of divide-integration. Several formulations related to the resinvelocity, resin filling time and resin flow pressure were proposed accurately. Good agreement was found between theexperimental result s and numerical predictive values. The deduced formulations could provide the theoretical basisfor suitably designing RTM filling parameters.
The filling process of RTM for the two step 3D braid shell preform with a varying section was investigated theoretically by employing a calculating method of divide-integration. Several formulations related to the resinvelocity, resin filling time and resin flow pressure were proposed accurately. Good agreement was found between theexperimental result s and numerical predictive values. The deduced formulations could provide the theoretical basisfor suitably designing RTM filling parameters.
2005, 22(3): 140-144.
Abstract:
The tensile failure mechanism of composite laminates with the damage of a hole was studied af ter beingrepaired with one-sided bonding. The out-of-plane displacement of the center point of the repaired laminates, tensilest rength and st rain dist ribution were measured. The influence of the patch size and thickness on tensile st rengthof the repaired laminates was examined experimentally. The result s demonst rate that increasing the patch thicknessand it s diameter can improve motherboard tensile st rength. However, enhancing the thickness of the patch will increase the out-of-plane displacement of the laminates. When undertaking computational analysis of one-side bondedlaminates without any support on the unloaded side, it is necessary to consider the effect s of the bending moment resulted f rom the eccent ric load. A three-dimensional finite element analysis was performed to detect the failure mechanism and predict the tensile st rength of the repaired specimens with delamination criterion. It was found that thefailure began in the first interface of the motherboard under the patch at the edge of hole or the patch. The analysisdata are good agreement with the test results.
The tensile failure mechanism of composite laminates with the damage of a hole was studied af ter beingrepaired with one-sided bonding. The out-of-plane displacement of the center point of the repaired laminates, tensilest rength and st rain dist ribution were measured. The influence of the patch size and thickness on tensile st rengthof the repaired laminates was examined experimentally. The result s demonst rate that increasing the patch thicknessand it s diameter can improve motherboard tensile st rength. However, enhancing the thickness of the patch will increase the out-of-plane displacement of the laminates. When undertaking computational analysis of one-side bondedlaminates without any support on the unloaded side, it is necessary to consider the effect s of the bending moment resulted f rom the eccent ric load. A three-dimensional finite element analysis was performed to detect the failure mechanism and predict the tensile st rength of the repaired specimens with delamination criterion. It was found that thefailure began in the first interface of the motherboard under the patch at the edge of hole or the patch. The analysisdata are good agreement with the test results.
2005, 22(3): 145-149.
Abstract:
This paper present s design studies of aeroelastic optimization of a high-aspect-ratio composite wingusing a genetic/ sensitivity-based hybrid algorithm. The design studies were carried out under the conditions ofmeeting multiple const raint s including strength, displacement, divergence speed and flutter speed. In the course ofoptimization, the thickness of plies of wing component s was considered as design variables, while the minimum ofthe st ructural weight as an objective function. The present work has made it clear that the problems with thebending deformation should be given serious consideration in the st ructural design of high-aspect-ratio compositewings because it has great effect s on the final optimized weight . It is also obvious that the wing st ructures formed onthe basis of st ress design criteria could hardly fulfill the requirement s on the bending deformation. A satisfactoryresult could be obtained at a reasonable cost of computational work by means of the genetic/ sensitivity-based hybridalgorithm in the aeroelastic optimization design of high-aspect-ratio composite wings.
This paper present s design studies of aeroelastic optimization of a high-aspect-ratio composite wingusing a genetic/ sensitivity-based hybrid algorithm. The design studies were carried out under the conditions ofmeeting multiple const raint s including strength, displacement, divergence speed and flutter speed. In the course ofoptimization, the thickness of plies of wing component s was considered as design variables, while the minimum ofthe st ructural weight as an objective function. The present work has made it clear that the problems with thebending deformation should be given serious consideration in the st ructural design of high-aspect-ratio compositewings because it has great effect s on the final optimized weight . It is also obvious that the wing st ructures formed onthe basis of st ress design criteria could hardly fulfill the requirement s on the bending deformation. A satisfactoryresult could be obtained at a reasonable cost of computational work by means of the genetic/ sensitivity-based hybridalgorithm in the aeroelastic optimization design of high-aspect-ratio composite wings.
2005, 22(3): 150-155.
Abstract:
A new multilayer shell element with relative degrees-of-freedom (DOF) was developed for modelinglaminated composite shells of ten used in aerospace st ructures. With this solid-type shell element, satisfactory resolution can be ensured even if a relatively coarse FE mesh is employed, and this element can be easily connected withother solid type element s. All of these features enable it s promising application in the simulation of modern composite st ructures, even if with varying thickness or complicated joint part s. For the buckling analysis of large-scaleaerospace composite laminated st ructures, a computational st rategy that combines the rotationally periodic FEmethod and this new shell element is implemented successfully. The numerical examples show the efficiency andaccuracy of the proposed computational strategy.
A new multilayer shell element with relative degrees-of-freedom (DOF) was developed for modelinglaminated composite shells of ten used in aerospace st ructures. With this solid-type shell element, satisfactory resolution can be ensured even if a relatively coarse FE mesh is employed, and this element can be easily connected withother solid type element s. All of these features enable it s promising application in the simulation of modern composite st ructures, even if with varying thickness or complicated joint part s. For the buckling analysis of large-scaleaerospace composite laminated st ructures, a computational st rategy that combines the rotationally periodic FEmethod and this new shell element is implemented successfully. The numerical examples show the efficiency andaccuracy of the proposed computational strategy.
2005, 22(3): 156-161.
Abstract:
The boundary element method (BEM) is proposed to analyze the elasto-plastic problems of 2-D orthot ropic st ructures. The boundary integral equation, internal st ress expression, BEM analysis formulae and elastoplastic st ress computation were established, respectively. In the elasto-plastic analysis, Hill-Tsai yielding criterionwas adopted, and the initial st ress method and tangent predictor-radial return algorithm were used to determine thereal st ress state. The elasto-plastic st resses and plastic zones of 2-D orthot ropic st ructures were analyzed with theproposed method, and some numerical result s were compared with the existing ones. Good agreement was observed,which demonst rates the validity of the present BEM in elaso-plastic problems of 2-D orthot ropic st ructures.
The boundary element method (BEM) is proposed to analyze the elasto-plastic problems of 2-D orthot ropic st ructures. The boundary integral equation, internal st ress expression, BEM analysis formulae and elastoplastic st ress computation were established, respectively. In the elasto-plastic analysis, Hill-Tsai yielding criterionwas adopted, and the initial st ress method and tangent predictor-radial return algorithm were used to determine thereal st ress state. The elasto-plastic st resses and plastic zones of 2-D orthot ropic st ructures were analyzed with theproposed method, and some numerical result s were compared with the existing ones. Good agreement was observed,which demonst rates the validity of the present BEM in elaso-plastic problems of 2-D orthot ropic st ructures.
2005, 22(3): 162-167.
Abstract:
The exact solution of piezoelastic laminated cylindrical shells embedded with shear piezoelect ric actuators was discussed1Under the local surface coordinates, each of the response quantities of every layer of the shellwas expanded in a double Fourier series1 Eight first-order ordinary homogeneous differential equations with variablecoefficient s were generated using state-space approach. The solutions of displacement, st ress and elect ric potentialof the cylindrical shell were got using the Frobenius method1 The numerical result s show the different effect s of thethickness ratios on the response quantities for mechanical and elect ric loads : (1) the axial displacement exhibit s azigzag variation for various thickness shells, but approaches linear dist ribution through the entire shell thickness forthin shells under mechanical loading ; ( 2 ) t ransverse st resses σz and τθz show st rong nonlinear under elect ricpotentials, but are piecewise linear for thin shells under mechanical loading ; (3) the elect ric potential is piecewiselinear for both elect ric and mechanical loads1 The result s could help to verify other laminate theories for multilayercylindrical shells with shear actuators.
The exact solution of piezoelastic laminated cylindrical shells embedded with shear piezoelect ric actuators was discussed1Under the local surface coordinates, each of the response quantities of every layer of the shellwas expanded in a double Fourier series1 Eight first-order ordinary homogeneous differential equations with variablecoefficient s were generated using state-space approach. The solutions of displacement, st ress and elect ric potentialof the cylindrical shell were got using the Frobenius method1 The numerical result s show the different effect s of thethickness ratios on the response quantities for mechanical and elect ric loads : (1) the axial displacement exhibit s azigzag variation for various thickness shells, but approaches linear dist ribution through the entire shell thickness forthin shells under mechanical loading ; ( 2 ) t ransverse st resses σz and τθz show st rong nonlinear under elect ricpotentials, but are piecewise linear for thin shells under mechanical loading ; (3) the elect ric potential is piecewiselinear for both elect ric and mechanical loads1 The result s could help to verify other laminate theories for multilayercylindrical shells with shear actuators.
2005, 22(3): 168-174.
Abstract:
A three-dimensional progressive damage model was developed for predicting the damage accumulation ofbolted double-lap joint s in fibre-reinforced plastics under in-plane tensile loading. The model is capable of simulatingthe four damage mechanisms and the correlation among them that are fibre breakage, fibre-mat rix shearing, mat rixcracking and delamination, which is also capable of assessing the ultimate tensile st rength of the joint s and of simulating the whole process of failure initiation, propagation and catast rophic failure of the st ructure. The paramet ricmethod was also used for bolted joint s in laminated composites with arbit rary lay-ups and geomet ries. Nine differentjoint s were used to predict the ultimate st rength of the joint s and analyze damage progression. An excellent agreement was found between the analytical predictions and the experimental data of the document .
A three-dimensional progressive damage model was developed for predicting the damage accumulation ofbolted double-lap joint s in fibre-reinforced plastics under in-plane tensile loading. The model is capable of simulatingthe four damage mechanisms and the correlation among them that are fibre breakage, fibre-mat rix shearing, mat rixcracking and delamination, which is also capable of assessing the ultimate tensile st rength of the joint s and of simulating the whole process of failure initiation, propagation and catast rophic failure of the st ructure. The paramet ricmethod was also used for bolted joint s in laminated composites with arbit rary lay-ups and geomet ries. Nine differentjoint s were used to predict the ultimate st rength of the joint s and analyze damage progression. An excellent agreement was found between the analytical predictions and the experimental data of the document .
2005, 22(3): 175-181.
Abstract:
The damping composite st ructures with three-layered damping materials were prepared. The dampingproperties were studied with the finite element method. The calculated result s are in good agreement with thosemeasured f rom the authors’test s. Based on the finite element model, the effect s of the geomet rical and physical parameters of damping materials on damping properties of composite st ructures were analyzed. The result s show thedamping material thickness, loss factor and modulus have evident effect s on the damping properties of the dampingcomposite st ructure, but the damping material density has no effect on them.
The damping composite st ructures with three-layered damping materials were prepared. The dampingproperties were studied with the finite element method. The calculated result s are in good agreement with thosemeasured f rom the authors’test s. Based on the finite element model, the effect s of the geomet rical and physical parameters of damping materials on damping properties of composite st ructures were analyzed. The result s show thedamping material thickness, loss factor and modulus have evident effect s on the damping properties of the dampingcomposite st ructure, but the damping material density has no effect on them.
