1988 Vol. 5, No. 1
1988, 5(1): 1-Ⅰ.
Abstract:
The void content in composites is determined by comparing measured composite depsity with theoretical density.The theoretical composite density is calculated from each component content and. its density.For multiphase composites,there are lots of parameters(various component contents and densities) included.,and every parameter is associated with certain error, So the total error resulting from the combination of these parameters is considerable.The more the number of components in composite the larger the error of void content.This paper analyzed the error of void content of a three-phase composite (glassfiber/carbon fiber/epoxy resin).The density of the resin in the composite is assumed to be the same as it is in a cast mass.It is,however,not strictly, correct.This paper described two methods of making cast resin. One is casted directly and the other is undergone vacuum treatment.The densities obtained from these two methods are not same.The former should be the minimum value of density of the resin matrix in composite and the latter should be the maximum value of the resin matrix density.There is no realistic way to determine the real value of the resin matrix density.It is the most serious error source in calculating void content in fiber rein-forced plastics to replace the density of resin matrix in composite with the density of bulk cast resin.This paper also indicated that as the number of components got more and/or as the void content got lower,the error in densities and contents of Components got more important.
The void content in composites is determined by comparing measured composite depsity with theoretical density.The theoretical composite density is calculated from each component content and. its density.For multiphase composites,there are lots of parameters(various component contents and densities) included.,and every parameter is associated with certain error, So the total error resulting from the combination of these parameters is considerable.The more the number of components in composite the larger the error of void content.This paper analyzed the error of void content of a three-phase composite (glassfiber/carbon fiber/epoxy resin).The density of the resin in the composite is assumed to be the same as it is in a cast mass.It is,however,not strictly, correct.This paper described two methods of making cast resin. One is casted directly and the other is undergone vacuum treatment.The densities obtained from these two methods are not same.The former should be the minimum value of density of the resin matrix in composite and the latter should be the maximum value of the resin matrix density.There is no realistic way to determine the real value of the resin matrix density.It is the most serious error source in calculating void content in fiber rein-forced plastics to replace the density of resin matrix in composite with the density of bulk cast resin.This paper also indicated that as the number of components got more and/or as the void content got lower,the error in densities and contents of Components got more important.
1988, 5(1): 7-Ⅱ.
Abstract:
The dynamic mechanical temperature spectrums of epoxy resin and the fiber-glass/epoxy composites have been studied under tensile-tensile stress in the range from 150℃ to 200℃.The effect of filler on the relaxation behaviour of epoxy matrix has been analyzed.It was oberserved that there is an additional peak (a'-peak) at the higher temperature side of the glass transtition peak (a-peak) on the damping-temperature curves of composites The new a'-peak was of obvious asymmetrical characters,and affected by the. contents and the surface treatments of fiber,whieh was considered as the effect of interface.The activation energy of a and a' transtitions have been measured by experiments.The relatpve height index ψ, was introduced for evaluating the contributions of interface.
The dynamic mechanical temperature spectrums of epoxy resin and the fiber-glass/epoxy composites have been studied under tensile-tensile stress in the range from 150℃ to 200℃.The effect of filler on the relaxation behaviour of epoxy matrix has been analyzed.It was oberserved that there is an additional peak (a'-peak) at the higher temperature side of the glass transtition peak (a-peak) on the damping-temperature curves of composites The new a'-peak was of obvious asymmetrical characters,and affected by the. contents and the surface treatments of fiber,whieh was considered as the effect of interface.The activation energy of a and a' transtitions have been measured by experiments.The relatpve height index ψ, was introduced for evaluating the contributions of interface.
1988, 5(1): 12-Ⅲ.
Abstract:
This paper has suggested a new method, front surface technique.It is a transient-state technique for the measurement of thermal conductivity of heterogenous and anisotropic composites.In this method the front surface of a cylindrical shaped specimen(diameter 10 mm,length 10-20 mm) is subjected to a burst of radiant energy coming from a laser. The resulting temperature change of the front surface of the specimen is recorded and thermal conductivity is computed from the temperature change of the front surface. This rrythod is developed on the basis of the Parker's method and has many advantages such as suitable size of specimen, fast sped of measurement and wide range of application etc, Theoretical model, formulas and the measuring results have been described in present paper.
This paper has suggested a new method, front surface technique.It is a transient-state technique for the measurement of thermal conductivity of heterogenous and anisotropic composites.In this method the front surface of a cylindrical shaped specimen(diameter 10 mm,length 10-20 mm) is subjected to a burst of radiant energy coming from a laser. The resulting temperature change of the front surface of the specimen is recorded and thermal conductivity is computed from the temperature change of the front surface. This rrythod is developed on the basis of the Parker's method and has many advantages such as suitable size of specimen, fast sped of measurement and wide range of application etc, Theoretical model, formulas and the measuring results have been described in present paper.
1988, 5(1): 21-Ⅲ.
Abstract:
A dynamic viscoelastic apparatus for "free-free" vibrating beam was developed.It can be used to continually measure the changes of the dynamic Young's modulus and mechanical loss with temperatures for large FRP samples from ambient temperature to 250℃.The method of supporting samples is simple and the judgement on the resonance of samples is easy,Only a few electronic instruments were employed.The repetitiveness of experimental results was good.This-apparatus was easy to be made and cheap.Based on the results obtained from the apparatus, the structure-molecular motion-mechanical property relationships of matrix resins can be established, and the heat resistance of composites can be estimated.These information is particularly useful for designing-application and quality control of composites.
A dynamic viscoelastic apparatus for "free-free" vibrating beam was developed.It can be used to continually measure the changes of the dynamic Young's modulus and mechanical loss with temperatures for large FRP samples from ambient temperature to 250℃.The method of supporting samples is simple and the judgement on the resonance of samples is easy,Only a few electronic instruments were employed.The repetitiveness of experimental results was good.This-apparatus was easy to be made and cheap.Based on the results obtained from the apparatus, the structure-molecular motion-mechanical property relationships of matrix resins can be established, and the heat resistance of composites can be estimated.These information is particularly useful for designing-application and quality control of composites.
1988, 5(1): 25-Ⅳ.
Abstract:
This paper presents experimental results of the penetration resistance for laminated glass/epoxy(GRP) and steel plate.Penetration resistance means resistance ability of target platy against projectile embedment or perforation.
This paper presents experimental results of the penetration resistance for laminated glass/epoxy(GRP) and steel plate.Penetration resistance means resistance ability of target platy against projectile embedment or perforation.
1988, 5(1): 30-Ⅴ.
Abstract:
This papsr provided a camsteel belt winder.An endless steel belt,linked up from head to end,formed motion surface which has both rotary and forward rectilinear motion.This surface can be used for shaping products and as the the continuous transporter of the products,Filament-wound GRP pipe was continuously maed on it.This paper analyzed state of forces in the cam-steel belt mechanisms and proved that steel belt can easily move along the axis of the mandrel and not slide along the periphery only by the reasonable construction of the mandrel.
This papsr provided a camsteel belt winder.An endless steel belt,linked up from head to end,formed motion surface which has both rotary and forward rectilinear motion.This surface can be used for shaping products and as the the continuous transporter of the products,Filament-wound GRP pipe was continuously maed on it.This paper analyzed state of forces in the cam-steel belt mechanisms and proved that steel belt can easily move along the axis of the mandrel and not slide along the periphery only by the reasonable construction of the mandrel.
1988, 5(1): 37-Ⅵ.
Abstract:
With isothermal and dynamic method,an analysis was made on the curing reaction of 250℃ high temperature strain gauge adhesive composed of unsaturated polyester 3301,styrcne,cyclohexanone peroxide and cobalt(Ⅱ) naphtheqnate by using CDR-1 differential scanning calorimeter.Thermal effect(ΔH) and curing parameters were obtained in isothermal and dynamic conditions. Apparent activity energy (ΔE) in isothermal and dynamic conditions were computed by using Arrhenius and Kissinger's equations. The results obtained from this work provided very important information for determining processing conditions of 250℃ high temperture stain gauae adhesive.
With isothermal and dynamic method,an analysis was made on the curing reaction of 250℃ high temperature strain gauge adhesive composed of unsaturated polyester 3301,styrcne,cyclohexanone peroxide and cobalt(Ⅱ) naphtheqnate by using CDR-1 differential scanning calorimeter.Thermal effect(ΔH) and curing parameters were obtained in isothermal and dynamic conditions. Apparent activity energy (ΔE) in isothermal and dynamic conditions were computed by using Arrhenius and Kissinger's equations. The results obtained from this work provided very important information for determining processing conditions of 250℃ high temperture stain gauae adhesive.
1988, 5(1): 43-Ⅵ.
Abstract:
The rheological properties of the glass/UP systems which was obtained as a result of the treatment of glass fibers by two different coupling agents (organic silicane and titanate) was determined.The excperimental results show that the Theological properties of the glass/UP systems depend not only on the form of the strueture formed in interface,but also on molecular structure coupling agent.
The rheological properties of the glass/UP systems which was obtained as a result of the treatment of glass fibers by two different coupling agents (organic silicane and titanate) was determined.The excperimental results show that the Theological properties of the glass/UP systems depend not only on the form of the strueture formed in interface,but also on molecular structure coupling agent.
1988, 5(1): 50-Ⅶ.
Abstract:
The piezoelectric composites were prepared by PZT ceramic powders (inclusions) and synthetic rubbers(matrix).The effect of several factors on the piezoelectric properties of the composits was studied by measuring piezoelectric and dielectric constants, and using scanning electron microscope and dielectric spectroscopy.The results show that the piezoelectric constants d33 of the composites increase with the increasing of the PZT volume fraction φ,the dielectric constants ε1 of the rubbers and the piezoelectric constants d33 of PZT ceramics,and decrease with increasing dielectric constant ε2 of ceramics powders.The piezoelectric constants d33 of the composites can be expressed as d33=15φε1d33/(1-φ)(2+3φ)ε2.
The piezoelectric composites were prepared by PZT ceramic powders (inclusions) and synthetic rubbers(matrix).The effect of several factors on the piezoelectric properties of the composits was studied by measuring piezoelectric and dielectric constants, and using scanning electron microscope and dielectric spectroscopy.The results show that the piezoelectric constants d33 of the composites increase with the increasing of the PZT volume fraction φ,the dielectric constants ε1 of the rubbers and the piezoelectric constants d33 of PZT ceramics,and decrease with increasing dielectric constant ε2 of ceramics powders.The piezoelectric constants d33 of the composites can be expressed as d33=15φε1d33/(1-φ)(2+3φ)ε2.
1988, 5(1): 56-Ⅶ.
Abstract:
In the present study we used gaseous oxidative procedure which carried out, with simple equipment,easy operation and likable with manufacturing line of carbon fibres.By using gaseous oxidation of carbon fibres an inter-laminar shear, strength (ILSS) of the carbon fibre reinforced plastic(CFRP) Can be increased by 36-56%.This is attributed to the increased concentration of chemical fuactional groups on the fibre surface.It was found that tensile serength of carbon fibre can be increased by 11-31% because of the removal of surface flaws.
In the present study we used gaseous oxidative procedure which carried out, with simple equipment,easy operation and likable with manufacturing line of carbon fibres.By using gaseous oxidation of carbon fibres an inter-laminar shear, strength (ILSS) of the carbon fibre reinforced plastic(CFRP) Can be increased by 36-56%.This is attributed to the increased concentration of chemical fuactional groups on the fibre surface.It was found that tensile serength of carbon fibre can be increased by 11-31% because of the removal of surface flaws.
1988, 5(1): 62-XI.
Abstract:
The cyclization machanism of polyacrylonitrile(PAN) catalyzed by Yin-tetrachloride has been studied in the present paper. The experimental results show that the catalytic reaction is through the succesive co mplexation betty een tin atom in SnCl4 and CN group in PAN. The suggested cyclization machanism is described in the following.
The cyclization machanism of polyacrylonitrile(PAN) catalyzed by Yin-tetrachloride has been studied in the present paper. The experimental results show that the catalytic reaction is through the succesive co mplexation betty een tin atom in SnCl4 and CN group in PAN. The suggested cyclization machanism is described in the following.
1988, 5(1): 67-XI.
Abstract:
Some of the mechanical behaviours of hybrid fibre composites were considered as the hybrid effect which is defined as a positive or negative deviation of a certain mechanical prorerty from the rule of mixture.The current theories about the hybrid effect were reviewed.The main factors affecting the hybrid effect were the properties of components,structure of hybrids and the interface between fibres and resin.The hybrid effect on the fracture strain of fibre and the strength of hybrids can be explaineds by the theories of fracture mechanics(thermodynamics) and micromechanics(statistics), The hybrid effect on fracture energy of hybrids depends on the hybrid structure and loading conditions.
Some of the mechanical behaviours of hybrid fibre composites were considered as the hybrid effect which is defined as a positive or negative deviation of a certain mechanical prorerty from the rule of mixture.The current theories about the hybrid effect were reviewed.The main factors affecting the hybrid effect were the properties of components,structure of hybrids and the interface between fibres and resin.The hybrid effect on the fracture strain of fibre and the strength of hybrids can be explaineds by the theories of fracture mechanics(thermodynamics) and micromechanics(statistics), The hybrid effect on fracture energy of hybrids depends on the hybrid structure and loading conditions.
1988, 5(1): 74-X.
Abstract:
Experiments of the moduli and the strengths of tensile,compression,shear and bending and the impact toughness were conducted for several kinds of plant fiber reinforced resin composites reported in Reference 1.Failure mechanism of the plant composites were analyzed by means of scanning electron microscopy(SEM) and acoustic emission(AE), Experimental data showed that, the mechanical properties tested here in for the plant composites were close to those of wood such as Korean pine and China fir,but better than those of fiberboard. The strengths of the plant composites were found dependent on the strengths of their constituents and the adhesion and binding force between fibers and matrix,fibers and fibers.
Experiments of the moduli and the strengths of tensile,compression,shear and bending and the impact toughness were conducted for several kinds of plant fiber reinforced resin composites reported in Reference 1.Failure mechanism of the plant composites were analyzed by means of scanning electron microscopy(SEM) and acoustic emission(AE), Experimental data showed that, the mechanical properties tested here in for the plant composites were close to those of wood such as Korean pine and China fir,but better than those of fiberboard. The strengths of the plant composites were found dependent on the strengths of their constituents and the adhesion and binding force between fibers and matrix,fibers and fibers.
