1993 Vol. 10, No. 4
1993, 10(4): 1-7.
Abstract:
This paper gives an analysis of composite plane shear performance of an improved for-connecting-rod-frame method and related compression performance.It helas one to measure the strain distribution of experimental gauge section, and offers a reasonable of judging the instabitityof material.
This paper gives an analysis of composite plane shear performance of an improved for-connecting-rod-frame method and related compression performance.It helas one to measure the strain distribution of experimental gauge section, and offers a reasonable of judging the instabitityof material.
1993, 10(4): 9-12.
Abstract:
Tensile stress was applied to the fibe: repreg to modify the residual streases in ARALL during curing. The residual stresses in as cured and prestressd ARA.LL were analysed, and the relationships between residual stress and prestresset different temperatures were given.The residual stresses were measured by means of strain gauges.The influences of prestxess on tensile and fatigue properties of ARALL were also studied.
Tensile stress was applied to the fibe: repreg to modify the residual streases in ARALL during curing. The residual stresses in as cured and prestressd ARA.LL were analysed, and the relationships between residual stress and prestresset different temperatures were given.The residual stresses were measured by means of strain gauges.The influences of prestxess on tensile and fatigue properties of ARALL were also studied.
1993, 10(4): 13-22.
Abstract:
In the paper, tiLe reduced bendinb stiffnss (RBS) method is used to treat the bending of ussymmetricwlly laminated plates as symmetrical problems in form so that transverse chear deformation is considered.Then their solution procedures are greatly simplified.Numerical results show that the RBS method is found to yield Bufficient accuracy when the number of laminates is greater than 2.
In the paper, tiLe reduced bendinb stiffnss (RBS) method is used to treat the bending of ussymmetricwlly laminated plates as symmetrical problems in form so that transverse chear deformation is considered.Then their solution procedures are greatly simplified.Numerical results show that the RBS method is found to yield Bufficient accuracy when the number of laminates is greater than 2.
1993, 10(4): 23-31.
Abstract:
In this paper, an elasticity solution for anisotropic laminated circular shells under axi symmetric loads is given in terms of series.Several groups of shells are analyzed and the results are compared with the results from the classical shell theory.
In this paper, an elasticity solution for anisotropic laminated circular shells under axi symmetric loads is given in terms of series.Several groups of shells are analyzed and the results are compared with the results from the classical shell theory.
1993, 10(4): 33-42.
Abstract:
On the basis of anisotropic mathematical elasticity, using multiple conformal representation, the stress functions of multiple complex variables for an infinite multiply-connected anisotropic plate are derived. The functions are expanded in the Fourier series on unit circles,and the unknown coefficients of the functions are determined by undetermined coefficients method.Then the stresses in the plate can be calculated.A plate containing multiple elliptical holes or cracks is discussed, and a corresponding FOR-TRAN77 prpgram is developed.Five examples are given.The results show that this method is very effective and convenient.
On the basis of anisotropic mathematical elasticity, using multiple conformal representation, the stress functions of multiple complex variables for an infinite multiply-connected anisotropic plate are derived. The functions are expanded in the Fourier series on unit circles,and the unknown coefficients of the functions are determined by undetermined coefficients method.Then the stresses in the plate can be calculated.A plate containing multiple elliptical holes or cracks is discussed, and a corresponding FOR-TRAN77 prpgram is developed.Five examples are given.The results show that this method is very effective and convenient.
1993, 10(4): 43-48,56.
Abstract:
A method is presented for carrying out nonlinear thermal buckling anlysis of composite laminates,based on a high-order displacement theory andamodified Hahn-Tsai nonlinear constitutive model.The high-order displacement theory takes account for both transverse shear deform ation and transverse normal strain effects.The nonlinear constitutive model includes nonlinearity not only between shear stresses and shear strains but also between transverse normal stresses a.nd strains.A damping parameter approach is used in order to improve the accuracy of solutions.Numerical results show that material nonlinearities significantly affects nonlinear thermal buckling behaviors of composite laminates.
A method is presented for carrying out nonlinear thermal buckling anlysis of composite laminates,based on a high-order displacement theory andamodified Hahn-Tsai nonlinear constitutive model.The high-order displacement theory takes account for both transverse shear deform ation and transverse normal strain effects.The nonlinear constitutive model includes nonlinearity not only between shear stresses and shear strains but also between transverse normal stresses a.nd strains.A damping parameter approach is used in order to improve the accuracy of solutions.Numerical results show that material nonlinearities significantly affects nonlinear thermal buckling behaviors of composite laminates.
1993, 10(4): 49-56.
Abstract:
In this paper, the asymptotic solutions of free vibration of symmetric cross-ply laminated plates clamped at four edges resting on Winkler-Pasternak foundations are obtained under the consideration of transverse shear deformation by using the laminate theory established in〔1〕and Bolotin's method.The numerical results are presented for laminated pates with different ratios of length and thickness in the ease of different elastic and shear moduli of foundations.As a simple example, the frequencies of thick orthotropic plates on elastic foundations are calculated by using the formulae presented in the paper and compared with those given by the other paper. The comparison shows little difference between them.
In this paper, the asymptotic solutions of free vibration of symmetric cross-ply laminated plates clamped at four edges resting on Winkler-Pasternak foundations are obtained under the consideration of transverse shear deformation by using the laminate theory established in〔1〕and Bolotin's method.The numerical results are presented for laminated pates with different ratios of length and thickness in the ease of different elastic and shear moduli of foundations.As a simple example, the frequencies of thick orthotropic plates on elastic foundations are calculated by using the formulae presented in the paper and compared with those given by the other paper. The comparison shows little difference between them.
1993, 10(4): 57-64.
Abstract:
The fractography of interlaminarly failed epoxy matrix composite laminates was observed with the aid of a scanning electron microscopy in this work.The mechanism resulted in the formation of cleavage steps is analysed while influential factors upon the size and shape of those steps are discussed.The corelation of microcrack propagation in the delamination of the composites to cleavage step and river pattern is explored in the final part of this paper.
The fractography of interlaminarly failed epoxy matrix composite laminates was observed with the aid of a scanning electron microscopy in this work.The mechanism resulted in the formation of cleavage steps is analysed while influential factors upon the size and shape of those steps are discussed.The corelation of microcrack propagation in the delamination of the composites to cleavage step and river pattern is explored in the final part of this paper.
1993, 10(4): 65-69.
Abstract:
Influence of five kinds coupling agents on electrical and mechanical properties of glass fiber/epoxy laminated plate is discussed in this paper.The resuits are shown that after glass fiber being treated with coupling agent and activation energy of glass fiber for wetting being decreased, the reaction activity and wettability between glass fiber and matrix epoxy resin can be improved.A good interface adhesion of glass fiber/epoxy results in an improvement of electrical and mechanical properties of gjasp fiber/epoxy laminated plast.
Influence of five kinds coupling agents on electrical and mechanical properties of glass fiber/epoxy laminated plate is discussed in this paper.The resuits are shown that after glass fiber being treated with coupling agent and activation energy of glass fiber for wetting being decreased, the reaction activity and wettability between glass fiber and matrix epoxy resin can be improved.A good interface adhesion of glass fiber/epoxy results in an improvement of electrical and mechanical properties of gjasp fiber/epoxy laminated plast.
1993, 10(4): 71-76.
Abstract:
The fiber-resin adhesion has been reinforced by plasma treatment on Ultra-high Molecular Weight Polyethylene(UHMW-PE)fibers. The mechanism of the surface change,as is reported in this paper, has been studied by the pull-out test,XPS,SEM, contact angle measurements. Giving the quantitative an alysis of the applied forces affecting the surface adhesion, we discuss the roles of the three main factore playing in the fiberresin adhesion,and their relation to plasma parameters.The three main factors are the key mechanimal effects,the the mical bonding effects and nonpolar dispersion force.
The fiber-resin adhesion has been reinforced by plasma treatment on Ultra-high Molecular Weight Polyethylene(UHMW-PE)fibers. The mechanism of the surface change,as is reported in this paper, has been studied by the pull-out test,XPS,SEM, contact angle measurements. Giving the quantitative an alysis of the applied forces affecting the surface adhesion, we discuss the roles of the three main factore playing in the fiberresin adhesion,and their relation to plasma parameters.The three main factors are the key mechanimal effects,the the mical bonding effects and nonpolar dispersion force.
1993, 10(4): 77-84.
Abstract:
In this paper, polypropylene melts filled with calcium carbonate powder, glass beads or mica flakes through aifferent surface treatments have been studied by means of RMS-605. The integrated knowledges of characteristic rheological material functions in steady or aynamic shear flow and the solid mechanical properties rrovide a way to understated the interfacial situation.
In this paper, polypropylene melts filled with calcium carbonate powder, glass beads or mica flakes through aifferent surface treatments have been studied by means of RMS-605. The integrated knowledges of characteristic rheological material functions in steady or aynamic shear flow and the solid mechanical properties rrovide a way to understated the interfacial situation.
1993, 10(4): 83-89.
Abstract:
A study was made to solid particle erosion in glass/epoxy composites.The results are shown that theerosion rate increases with theincreasing of diameter, volocity and impact angle of the solid particles.The erosion rate is also related with fiber orientation,it is minimum at 0°:and maximum at 90°.
A study was made to solid particle erosion in glass/epoxy composites.The results are shown that theerosion rate increases with theincreasing of diameter, volocity and impact angle of the solid particles.The erosion rate is also related with fiber orientation,it is minimum at 0°:and maximum at 90°.
1993, 10(4): 91-95.
Abstract:
Starting from the matrix material of Carbon/Carbon composite,prosessing conditions and effects of the modified matrix containingpitch and coke doped with oxides have been investigated.Results show that matrix modification with the oxide dopants not only improves the oxidation resistance,but also affects the properties of the Carbon/Carbon composi to.High performance Carbon/Carbon composite can be obtained so long as the procedure conditions are appropriately controlled.
Starting from the matrix material of Carbon/Carbon composite,prosessing conditions and effects of the modified matrix containingpitch and coke doped with oxides have been investigated.Results show that matrix modification with the oxide dopants not only improves the oxidation resistance,but also affects the properties of the Carbon/Carbon composi to.High performance Carbon/Carbon composite can be obtained so long as the procedure conditions are appropriately controlled.
1993, 10(4): 97-102.
Abstract:
It is obtanred that the properties (σf,Cox/Cgr,surface defect) of two kinds of fiber, PAN-based and pitch-based carbon fiber, change with the variation of anod surface conditions in this work.The chemical activity and physical activity of carbon fiber surface can be greatly increased by anod surface treatment.The experiment results show that four kiads of carbon-oxide a.nd the tiny surface defect can be formed on the surface of carbon fibers by and surface treatment.The ratio Cox/Cgr,the relative total content of carbon-oxide,and the size and amount of tiny surface defect increased with the increase of anodic potential.The shape of surface defect of PAN-based carbon fiber is different from that of pitchbased carbon fiber.It is observed that the anodic potential is the most important parameter for anod surface treatment of carbon fibers.
It is obtanred that the properties (σf,Cox/Cgr,surface defect) of two kinds of fiber, PAN-based and pitch-based carbon fiber, change with the variation of anod surface conditions in this work.The chemical activity and physical activity of carbon fiber surface can be greatly increased by anod surface treatment.The experiment results show that four kiads of carbon-oxide a.nd the tiny surface defect can be formed on the surface of carbon fibers by and surface treatment.The ratio Cox/Cgr,the relative total content of carbon-oxide,and the size and amount of tiny surface defect increased with the increase of anodic potential.The shape of surface defect of PAN-based carbon fiber is different from that of pitchbased carbon fiber.It is observed that the anodic potential is the most important parameter for anod surface treatment of carbon fibers.
1993, 10(4): 103-108134.
Abstract:
A kind of microwave absorbing material consisting of electromagnetic lossy substance,resonator and epoxy resin was prepared.The permeability and permittivitp of the composite were measured by using of an HP8510B microwave vector network analyzer.It has been found that the material works mainly in dielectric loss mechanism.Whereas the magnetic loss is trival in microwave attenuation.An equivalent circuit was used to simulate the composite in electromagnetic field followed by impedance analysis and power reflectivity calculation was carried out in a BASIC program. The tendancy of reflectivity variation with irequeacy determined by calculation is basically in agreement with that revealed by frequency scanning experiment performed with an HP8410C network analyzer.
A kind of microwave absorbing material consisting of electromagnetic lossy substance,resonator and epoxy resin was prepared.The permeability and permittivitp of the composite were measured by using of an HP8510B microwave vector network analyzer.It has been found that the material works mainly in dielectric loss mechanism.Whereas the magnetic loss is trival in microwave attenuation.An equivalent circuit was used to simulate the composite in electromagnetic field followed by impedance analysis and power reflectivity calculation was carried out in a BASIC program. The tendancy of reflectivity variation with irequeacy determined by calculation is basically in agreement with that revealed by frequency scanning experiment performed with an HP8410C network analyzer.
1993, 10(4): 109-134.
Abstract:
The matrix of the composite, Al/Al-A3Ni has a good thermal stability, so the fracture work and the fractal dimension can be changed by changing the tensile temperature.The fractal dimension was measured by means of fracture profile method(FPM).The results indicate that the fractal dimension can be divided into three parts,and the each part of the fractal dimension correspond to a certain part of the microstructure.The relationship between the fracture work and the fractal dimension was also studied in the paper.
The matrix of the composite, Al/Al-A3Ni has a good thermal stability, so the fracture work and the fractal dimension can be changed by changing the tensile temperature.The fractal dimension was measured by means of fracture profile method(FPM).The results indicate that the fractal dimension can be divided into three parts,and the each part of the fractal dimension correspond to a certain part of the microstructure.The relationship between the fracture work and the fractal dimension was also studied in the paper.
1993, 10(4): 115-122,96.
Abstract:
In this study C/Al cross-plied laminates with two stacking sequence used. (90/0/90)s and (90/0/90)s abricated by hot-press method in vacuum are used. A series of experim eats on fatigue damage and fatigue fracture are conducted using MTS NEW 810.The research works on the behavior of fatigue damage include that shakedown analysis for C/Al cross-plied laminates which relates stiffness reduction as a damage parameter is presented to prediet the stress range below which no fatigue damage accmulates in the laminate. Negt, the fatigue response of C/Al cross-plied laminates is developed at constaut maximum stress level,but with different values of 0S,which indicates the stiffness reduction at failure is reasonably similar.It is suggested that the failure criterion be determined by the maximum stress level.The results prerented for matrix fatigue damage indicate the existence of three distinct regions in the S-N plane in which one observes different responses of MMC to cyclic loadings.The three regions are:no fatigue damage region,damage accumunation region, frail,ture region.Fatigue fracture surfaces and interface characteristics can be examined using SEM, and matrix cracking,by taking photographs through a 30 to 60 power optical microscope.The results show that the fracture surfaces of C/Al cross-plied laminates are flateply cracking has three kinds of modeselocal interior delamination,matrix cracks and interaced debonding between composites wires and matrixs;the dourinated reson of fatigue failure are local ply damage and large scale fiber failures in the longitudinal plies:if the interface is made too strong,matrix fatigue cracks are more likely to propagate through fibers and lead to early la urinates fracture.More work is needed to determine the optimum fiber/matrix interface properties for the composites.
In this study C/Al cross-plied laminates with two stacking sequence used. (90/0/90)s and (90/0/90)s abricated by hot-press method in vacuum are used. A series of experim eats on fatigue damage and fatigue fracture are conducted using MTS NEW 810.The research works on the behavior of fatigue damage include that shakedown analysis for C/Al cross-plied laminates which relates stiffness reduction as a damage parameter is presented to prediet the stress range below which no fatigue damage accmulates in the laminate. Negt, the fatigue response of C/Al cross-plied laminates is developed at constaut maximum stress level,but with different values of 0S,which indicates the stiffness reduction at failure is reasonably similar.It is suggested that the failure criterion be determined by the maximum stress level.The results prerented for matrix fatigue damage indicate the existence of three distinct regions in the S-N plane in which one observes different responses of MMC to cyclic loadings.The three regions are:no fatigue damage region,damage accumunation region, frail,ture region.Fatigue fracture surfaces and interface characteristics can be examined using SEM, and matrix cracking,by taking photographs through a 30 to 60 power optical microscope.The results show that the fracture surfaces of C/Al cross-plied laminates are flateply cracking has three kinds of modeselocal interior delamination,matrix cracks and interaced debonding between composites wires and matrixs;the dourinated reson of fatigue failure are local ply damage and large scale fiber failures in the longitudinal plies:if the interface is made too strong,matrix fatigue cracks are more likely to propagate through fibers and lead to early la urinates fracture.More work is needed to determine the optimum fiber/matrix interface properties for the composites.
1993, 10(4): 123-126114.
Abstract:
The oxidation resistance of Mo/Ni3Al composite has been studied. The results show that the oxidation kinetics of Mo/Ni3Al composite at different temperatures obeys the parabolic law. The amounts of oxide increase obviously with that of the experimental temperature.MoO2 being oxidated to MoO3 at high temperature results in the decreasing of oxidation resistance of Mo/Ni3Al composite.
The oxidation resistance of Mo/Ni3Al composite has been studied. The results show that the oxidation kinetics of Mo/Ni3Al composite at different temperatures obeys the parabolic law. The amounts of oxide increase obviously with that of the experimental temperature.MoO2 being oxidated to MoO3 at high temperature results in the decreasing of oxidation resistance of Mo/Ni3Al composite.
1993, 10(4): 127-134.
Abstract:
The superhigh strength、amorphous metal ribbon reinforced higher character polymer matrix composites was studied. Using a suitable method of surface chemical treatment to amorphous metal ribbon, we find that it can increase the adhesive character of composites.And we used shear strength of composites to research adhesive character of amorphous metal ribbon reinforced polymer composites.Using SEM technique,we examine the interface of tbis kind composites and the surface of amorphous metal ribbon which is treated and untreated.
The superhigh strength、amorphous metal ribbon reinforced higher character polymer matrix composites was studied. Using a suitable method of surface chemical treatment to amorphous metal ribbon, we find that it can increase the adhesive character of composites.And we used shear strength of composites to research adhesive character of amorphous metal ribbon reinforced polymer composites.Using SEM technique,we examine the interface of tbis kind composites and the surface of amorphous metal ribbon which is treated and untreated.
