1992 Vol. 9, No. 3
1992, 9(3): 1-8.
Abstract:
The article describes the forming technology for composite materials of thermoplastic resin REEK and carbon fabric or glass fabric by hot pressing method.It is shown that the quality of composite material is related to the conditions of temperature,pressure,time,etc..Through the test of rheologic properties,the melting body which shows the fluid active energy and the viscosity of the melting body with the tempeperture of 40℃ under the same shear velocity have been calculated,and the dependentence of PEEK on the temperature is also investigated.The variation of processing parameters which is shown by the result obaained by ultrasonic C-scanning proves that this method has good selection properties and sensitivity compared with another method.
The article describes the forming technology for composite materials of thermoplastic resin REEK and carbon fabric or glass fabric by hot pressing method.It is shown that the quality of composite material is related to the conditions of temperature,pressure,time,etc..Through the test of rheologic properties,the melting body which shows the fluid active energy and the viscosity of the melting body with the tempeperture of 40℃ under the same shear velocity have been calculated,and the dependentence of PEEK on the temperature is also investigated.The variation of processing parameters which is shown by the result obaained by ultrasonic C-scanning proves that this method has good selection properties and sensitivity compared with another method.
THE GROWTH DYNAMICS OF INTERFACIAL CeAlO3 BETWEEN Al2O3 AND MEDIUM MANGANESE STEEL CONTAINING CERIUM
1992, 9(3): 9-12.
Abstract:
On the basis of theoretical analysis and interfacial structure study,the growth model of interfacial reaction product--CeAlO3 layer has been established,the relation between holding time t and the thickness S of CeAlO3 layer follows a parabola law--S=√2D(C1-CCA)(t-t0)/(CCA-CAC).The experimental results are in agreement with the theoretical model and the obtamed law.
On the basis of theoretical analysis and interfacial structure study,the growth model of interfacial reaction product--CeAlO3 layer has been established,the relation between holding time t and the thickness S of CeAlO3 layer follows a parabola law--S=√2D(C1-CCA)(t-t0)/(CCA-CAC).The experimental results are in agreement with the theoretical model and the obtamed law.
1992, 9(3): 13-18.
Abstract:
A new model describing the Extended Vapor-Liquid-Solid(EVLS) mechanism is proposed for revealing the growth of Reactive Self-composiing (RSC) material formed by direct oxidation of parent metal (Al_2.96Mg-7.60Si) at hight temperature.EVLS model has been investigated by mesas of optical microscopic analysis,SEM and EPMA.All the experimeats conducted demonstrate the EVLS model.
A new model describing the Extended Vapor-Liquid-Solid(EVLS) mechanism is proposed for revealing the growth of Reactive Self-composiing (RSC) material formed by direct oxidation of parent metal (Al_2.96Mg-7.60Si) at hight temperature.EVLS model has been investigated by mesas of optical microscopic analysis,SEM and EPMA.All the experimeats conducted demonstrate the EVLS model.
1992, 9(3): 19-22.
Abstract:
The structure and fracture is observed in SiCp/Al composites producing with casting method and compared with domestic and abroad.Low magnification observation shows that in the two kinds composites silicon carbide particulates are well distributed and no clustering is observed.With the high-magnification it is observed that most of the silicon-carbide particulates distributed around the grain interface forming ‘flower edge of grain'.The ‘bright spot' on the fracture of the SiCp/Al composites that can be seen with nake-yes maybe reflect the casting cavity.
The structure and fracture is observed in SiCp/Al composites producing with casting method and compared with domestic and abroad.Low magnification observation shows that in the two kinds composites silicon carbide particulates are well distributed and no clustering is observed.With the high-magnification it is observed that most of the silicon-carbide particulates distributed around the grain interface forming ‘flower edge of grain'.The ‘bright spot' on the fracture of the SiCp/Al composites that can be seen with nake-yes maybe reflect the casting cavity.
1992, 9(3): 23-26.
Abstract:
In this paper,the relation between the electric properties of C/Al Composite materiats and the volume fraction of reinforced fibers,as well as the arranging method of fiber and temperature were investigated.The experiment results reveal that the electric conductivity of C/Al Composite materials increase with the raising of fiber volume fraction,angle of fiber arranging and to mperature.
In this paper,the relation between the electric properties of C/Al Composite materiats and the volume fraction of reinforced fibers,as well as the arranging method of fiber and temperature were investigated.The experiment results reveal that the electric conductivity of C/Al Composite materials increase with the raising of fiber volume fraction,angle of fiber arranging and to mperature.
1992, 9(3): 27-31.
Abstract:
The superplastic pretreatment processes and superplastic defororation conditions of SiC particle reinforced LY12 alu minum composite produced by stirring casting method were studied.After the pretreatment of homogenizing annealing-hot inverted extrusion-warm rolling-recry-stallization,the SiCp/LY12 Composite exhibites good superplasticity.Under the deformation Condltions of 793K,6.4×10-4S-1,the maxium elongation of this material can reach 293%.The effects of SiC particles on the superplastic pretreatment and superplastic deformation were discussed.
The superplastic pretreatment processes and superplastic defororation conditions of SiC particle reinforced LY12 alu minum composite produced by stirring casting method were studied.After the pretreatment of homogenizing annealing-hot inverted extrusion-warm rolling-recry-stallization,the SiCp/LY12 Composite exhibites good superplasticity.Under the deformation Condltions of 793K,6.4×10-4S-1,the maxium elongation of this material can reach 293%.The effects of SiC particles on the superplastic pretreatment and superplastic deformation were discussed.
1992, 9(3): 33-36.
Abstract:
In this paper,the tribological behavior of ZL102/SiCp composite was investigated.The results indicate that the wear resistance of SiCp/Al composites is improved as SiC particles are mixed.Comparing the composite with its matrix alloy,it is found that the former has muchlower wear rate and better smeared wear resistance.The wear property of the composite depends on the amount and distribution of its reinforcemeat,as well as the interface condition between the reinforcement and matrix.
In this paper,the tribological behavior of ZL102/SiCp composite was investigated.The results indicate that the wear resistance of SiCp/Al composites is improved as SiC particles are mixed.Comparing the composite with its matrix alloy,it is found that the former has muchlower wear rate and better smeared wear resistance.The wear property of the composite depends on the amount and distribution of its reinforcemeat,as well as the interface condition between the reinforcement and matrix.
1992, 9(3): 37-42.
Abstract:
Tensile tests at various temperatures and physical properties measurement for SiCp/124Al composite were carried out,the aging response and abrasive wear properties were investigated.The results indicate that the composite exhibits high ambient temperature strength,modulus and low CTE.Moreover,the composite also displays excellent elevated temperature and cryogenic properties,and abrasive wear resistance.The aging response of the composite is evidently accelerated due to addition of SiC particulate.
Tensile tests at various temperatures and physical properties measurement for SiCp/124Al composite were carried out,the aging response and abrasive wear properties were investigated.The results indicate that the composite exhibits high ambient temperature strength,modulus and low CTE.Moreover,the composite also displays excellent elevated temperature and cryogenic properties,and abrasive wear resistance.The aging response of the composite is evidently accelerated due to addition of SiC particulate.
1992, 9(3): 43-46.
Abstract:
The effects of two aluminum matrix alloys,pure A1 and Ly12,on the mechanical properties of graphite fiber reinforced aluminum composite were investigated,and the mechanisms of effects were also studied.The results show that matrix alloys have a significant influence on the inerfacial state as well as the composition and distribution of the phases in the matrix,and finally on the properties of the Gr/Al composites.LY12,Compared with pure Al,deterioated greatly the tensile strength of the composites.
The effects of two aluminum matrix alloys,pure A1 and Ly12,on the mechanical properties of graphite fiber reinforced aluminum composite were investigated,and the mechanisms of effects were also studied.The results show that matrix alloys have a significant influence on the inerfacial state as well as the composition and distribution of the phases in the matrix,and finally on the properties of the Gr/Al composites.LY12,Compared with pure Al,deterioated greatly the tensile strength of the composites.
1992, 9(3): 47-50.
Abstract:
To improve the wettabitify between fiber and matrix,Ni、SiC-Ni were coated on the carbon fibers.It is observed by inf filtration of liquid Al that Ni coating can make fibers distribute well in the matrix,but single Ni coating results in the damage of carbon fibers.A brittle phase appears on the interface and matrix under Ni、SiC-Ni coating,and the strength of composite decreases dramatically.
To improve the wettabitify between fiber and matrix,Ni、SiC-Ni were coated on the carbon fibers.It is observed by inf filtration of liquid Al that Ni coating can make fibers distribute well in the matrix,but single Ni coating results in the damage of carbon fibers.A brittle phase appears on the interface and matrix under Ni、SiC-Ni coating,and the strength of composite decreases dramatically.
1992, 9(3): 51-57.
Abstract:
In this paper,the dislamination,crack growth and propagation between layers of a laminated circular plate subjected uniform pressure is investigated by virtue of the elastic-plastic theory with finite deformation.The crack of initial imperfection has a critical one,firstly the crack grows in the imperfect layer then it propagate to the nearest layers rapidly.The simulation results of a crack growth and its stressd Islam inated matrix layers are simplified as an elastic material with small modulus,then the difficulties of defining the separation or contact of the dislaminated interfaces could be avoided,the cost of the numcrical calculation is reduced considerably.
In this paper,the dislamination,crack growth and propagation between layers of a laminated circular plate subjected uniform pressure is investigated by virtue of the elastic-plastic theory with finite deformation.The crack of initial imperfection has a critical one,firstly the crack grows in the imperfect layer then it propagate to the nearest layers rapidly.The simulation results of a crack growth and its stressd Islam inated matrix layers are simplified as an elastic material with small modulus,then the difficulties of defining the separation or contact of the dislaminated interfaces could be avoided,the cost of the numcrical calculation is reduced considerably.
1992, 9(3): 59-70.
Abstract:
This paper presents a computation method for filament wound pressure vessel.With the equivalent cylindrical approximation,we have obtained the asymptotic solution for the problem.Numerical calculation shows that the result of asymptotic solution agrees with experiment and that of spline collocation technique solution.
This paper presents a computation method for filament wound pressure vessel.With the equivalent cylindrical approximation,we have obtained the asymptotic solution for the problem.Numerical calculation shows that the result of asymptotic solution agrees with experiment and that of spline collocation technique solution.
1992, 9(3): 71-78.
Abstract:
In this paper the static fundamental solutions of orthotropic thick plates are takes as the kernel function of boundary integral equation,The boundary integral equations for vibration analysis of orthotropic thick plate;are formulated by the method of weighted residuals.The numerical implementation of boundary integral equations is discussed in detail and serval examples of different boundary conditions are given to demonstrate the correctness of the present method.
In this paper the static fundamental solutions of orthotropic thick plates are takes as the kernel function of boundary integral equation,The boundary integral equations for vibration analysis of orthotropic thick plate;are formulated by the method of weighted residuals.The numerical implementation of boundary integral equations is discussed in detail and serval examples of different boundary conditions are given to demonstrate the correctness of the present method.
1992, 9(3): 79-84.
Abstract:
A mechanical model of anisotropic viscoelastic body is set up in this paper from the microstructure of the tooth of fibre reinforced plastic gears and the viscoelastic stress field is solved by the finite element method combined with the Laplace transformation technique.The Schaper's numerical inversion method is successfully improved by introducing a time converting factor and is used in this paper to transform the solution of the problem from the Laplace space to the physical space.It is found that the calculated results by the method presented are in good coincidence with tihe tested data.
A mechanical model of anisotropic viscoelastic body is set up in this paper from the microstructure of the tooth of fibre reinforced plastic gears and the viscoelastic stress field is solved by the finite element method combined with the Laplace transformation technique.The Schaper's numerical inversion method is successfully improved by introducing a time converting factor and is used in this paper to transform the solution of the problem from the Laplace space to the physical space.It is found that the calculated results by the method presented are in good coincidence with tihe tested data.
1992, 9(3): 85-91.
Abstract:
This paper presents a small deflection analysis for the buckling problem of the symmetical and antisymmetical sandwich plates with laminated cross-ply faces.Based on Hoff's sandwich plates hypothesis,the explicit expressions of buckling loads of simply-supported sandwich plates are obtained when loaded under uniaxial compression.Making use of these expression,the influence of the coupling effects of the faces on the critical loads is discussed.
This paper presents a small deflection analysis for the buckling problem of the symmetical and antisymmetical sandwich plates with laminated cross-ply faces.Based on Hoff's sandwich plates hypothesis,the explicit expressions of buckling loads of simply-supported sandwich plates are obtained when loaded under uniaxial compression.Making use of these expression,the influence of the coupling effects of the faces on the critical loads is discussed.
1992, 9(3): 93-103.
Abstract:
A shear-lag model is presented for analysis of load concentration of fibers adjacent to a crack in unidirectionally fibei-reinforced composites.The analytic solutions of stress concentration factors of fibers adjacent to a crack-tip are obtained by using this model.The maximum stress concentration factors are calculated of the fiber at the tip of a crack,and the numerical results show little difference with Hedgepeth's results.In addition,the concept of the average stress concentration factor is presented,and the affected length of the crack-tip fiber is defined by means of the value of the stress concentration factor.Its physical meaning is clear,and it increases gradually with expansion of the crack,which is in accordance with the actual case.Based upon the previous analysis,statistical analysis of failure of unidirectionally fiber-reinforced composites is done by;applying the method of the ultimate crack core model[2,3].The results are close to the experimental data,and those obtained by using the average stress concentration factors approach the experim ental data more closely.The ccmparison of the results here with the experimental data chows correctness of the method of the ultimate crack core model and feasibility of the affected ogrl and the average stress concentration factor in the analysis of crack propagetion.
A shear-lag model is presented for analysis of load concentration of fibers adjacent to a crack in unidirectionally fibei-reinforced composites.The analytic solutions of stress concentration factors of fibers adjacent to a crack-tip are obtained by using this model.The maximum stress concentration factors are calculated of the fiber at the tip of a crack,and the numerical results show little difference with Hedgepeth's results.In addition,the concept of the average stress concentration factor is presented,and the affected length of the crack-tip fiber is defined by means of the value of the stress concentration factor.Its physical meaning is clear,and it increases gradually with expansion of the crack,which is in accordance with the actual case.Based upon the previous analysis,statistical analysis of failure of unidirectionally fiber-reinforced composites is done by;applying the method of the ultimate crack core model[2,3].The results are close to the experimental data,and those obtained by using the average stress concentration factors approach the experim ental data more closely.The ccmparison of the results here with the experimental data chows correctness of the method of the ultimate crack core model and feasibility of the affected ogrl and the average stress concentration factor in the analysis of crack propagetion.
1992, 9(3): 105-110.
Abstract:
In this paper,the Shape Memory Alloy-NiTi wires are embeded in the epoxy plate and AL-plate.The photoelastic experiment,Moire' interferometry experiment and numerical analysis are investigated.The experiment and calculation result show that the effect of activly control of the crack growth for this novel composite component is obvious.
In this paper,the Shape Memory Alloy-NiTi wires are embeded in the epoxy plate and AL-plate.The photoelastic experiment,Moire' interferometry experiment and numerical analysis are investigated.The experiment and calculation result show that the effect of activly control of the crack growth for this novel composite component is obvious.
