1993 Vol. 10, No. 1
1993, 10(1): 1-7.
Abstract:
Almost all natural biomaterials are composite materials,such as bamboo,wood,bone and shell,etc..They have formed distinguished structures after millions of years of natural selection and evolution.In the present paper,the origination,development and some applications of bionics were reviewed and some optimal characteristics and superiorities of the tomposite structures of natural materials were studied.The result reveals that both plant and animal materials conform to the "Principle of Functional Adaptability".Finally,the self-healing abilities of trauma of bone and wood were studied,which provides the necessary preparation for the research of the self-healing of composite materials.
Almost all natural biomaterials are composite materials,such as bamboo,wood,bone and shell,etc..They have formed distinguished structures after millions of years of natural selection and evolution.In the present paper,the origination,development and some applications of bionics were reviewed and some optimal characteristics and superiorities of the tomposite structures of natural materials were studied.The result reveals that both plant and animal materials conform to the "Principle of Functional Adaptability".Finally,the self-healing abilities of trauma of bone and wood were studied,which provides the necessary preparation for the research of the self-healing of composite materials.
1993, 10(1): 9-18.
Abstract:
Using Differential Scanning Claorimeter,the accelerating effects of several accelerators on 4,4 Diaminodiphenyl Sulphone (DDS) are studied.Two electron-withdrawing compounds which have synergistic effect on the curing reaction of the resin system are utilized to cure it quickly at moderate temperature.After that,the orthogonal-regression optional design is applied to optimize formulations of the resin.The reliabilities of the resulted regression equations surpass 95 percent.And the curves plotted according to the regression equations by computer visually demonstrate the relationship between the formulations and properties of the resin.Finally,the optimum formulation which has excellent comprehensive properties is searched out with the assistance of computer.
Using Differential Scanning Claorimeter,the accelerating effects of several accelerators on 4,4 Diaminodiphenyl Sulphone (DDS) are studied.Two electron-withdrawing compounds which have synergistic effect on the curing reaction of the resin system are utilized to cure it quickly at moderate temperature.After that,the orthogonal-regression optional design is applied to optimize formulations of the resin.The reliabilities of the resulted regression equations surpass 95 percent.And the curves plotted according to the regression equations by computer visually demonstrate the relationship between the formulations and properties of the resin.Finally,the optimum formulation which has excellent comprehensive properties is searched out with the assistance of computer.
1993, 10(1): 19-26.
Abstract:
The compatibility,multiple transition and relaxation behaviour of PPS/PES blends and their composites reinforced by carbon fiber (CFPPS/PES) have been studied by internal friction analysis method.The experimental results show that;(1)there is interaction on a molecular-scale between PPS and PES in the blends and the blending ratio is the key facfor to determine the degree of such interaction;(2) there is a rather wide continuous distribution of relaxation times for the secondary relaxation of PES in both the blends and the composites,and the half-width of the relaxation time distribution function for the relaxation process changes with the blending ratio and reaches maximum in the case of 80% PES;(3)PPS and PES are thermodynamically metastable,and heat treatment increases the degree of phase separation of PPS from PES and weakens phase interaction;(4) low temperature therms,l history exerts considerable influence on the glass transition of PPS,the peak height and peak temperature of which decrease with a rise in starting temperature.
The compatibility,multiple transition and relaxation behaviour of PPS/PES blends and their composites reinforced by carbon fiber (CFPPS/PES) have been studied by internal friction analysis method.The experimental results show that;(1)there is interaction on a molecular-scale between PPS and PES in the blends and the blending ratio is the key facfor to determine the degree of such interaction;(2) there is a rather wide continuous distribution of relaxation times for the secondary relaxation of PES in both the blends and the composites,and the half-width of the relaxation time distribution function for the relaxation process changes with the blending ratio and reaches maximum in the case of 80% PES;(3)PPS and PES are thermodynamically metastable,and heat treatment increases the degree of phase separation of PPS from PES and weakens phase interaction;(4) low temperature therms,l history exerts considerable influence on the glass transition of PPS,the peak height and peak temperature of which decrease with a rise in starting temperature.
1993, 10(1): 27-33.
Abstract:
In this paper,the authors deal with the composite effect and the conditions of coupled reaction of a heterogeneous system involving hydrophobic rubber as continuous phase and the close coupling modified clay as dispersed phase.The mode of coupling at the surface of hydrophilic clay is explored primarily by making use of IR sapetrometry.
In this paper,the authors deal with the composite effect and the conditions of coupled reaction of a heterogeneous system involving hydrophobic rubber as continuous phase and the close coupling modified clay as dispersed phase.The mode of coupling at the surface of hydrophilic clay is explored primarily by making use of IR sapetrometry.
1993, 10(1): 35-39.
Abstract:
In this paper,interfacial shape and structure of the carbon fiber/palyimide (CF/PMR-15) composite (CFRP) has been directly observed by TEM.The results show that interfacial shape and structure of CFRP are related to the surfaces of carbon fiber,and influence the mechanical properties of CFRP.
In this paper,interfacial shape and structure of the carbon fiber/palyimide (CF/PMR-15) composite (CFRP) has been directly observed by TEM.The results show that interfacial shape and structure of CFRP are related to the surfaces of carbon fiber,and influence the mechanical properties of CFRP.
1993, 10(1): 41-45.
Abstract:
Systematic study has been made on the effect of heat treatment on the mechanical properties of carbon fibre with Ni coating,SiC coatingand SiC-Ni duplex coating.It is shown that tensile strength of the fibre increases with the increasing of thickness of SiC coating.The fracture way of the fibre coated with SiC is pull-out.The strength of SiGcoated fibre does not decrease after heat treatment.The strength of SiC-Ni-coated fibre decreases slowly during heat treatment.The strength of Ni-coated fibre decreases quickly.The reason that the strength of the fibre decreases and fracture mechanism of the coated fibre are analysed.
Systematic study has been made on the effect of heat treatment on the mechanical properties of carbon fibre with Ni coating,SiC coatingand SiC-Ni duplex coating.It is shown that tensile strength of the fibre increases with the increasing of thickness of SiC coating.The fracture way of the fibre coated with SiC is pull-out.The strength of SiGcoated fibre does not decrease after heat treatment.The strength of SiC-Ni-coated fibre decreases slowly during heat treatment.The strength of Ni-coated fibre decreases quickly.The reason that the strength of the fibre decreases and fracture mechanism of the coated fibre are analysed.
1993, 10(1): 47-50.
Abstract:
In this paper,the process of aging precipitation in the Al2O3/6061 compositestry was investigated.Hardness,differential scanning calorimetry (DSC),and transmission electron microscopy were employed.Results show that the main precipitation phase of peak hardness is β'-phase,and it is suggested that solution treated at 530℃,aging at 160℃ for 8 hours is an ideal aging technique.
In this paper,the process of aging precipitation in the Al2O3/6061 compositestry was investigated.Hardness,differential scanning calorimetry (DSC),and transmission electron microscopy were employed.Results show that the main precipitation phase of peak hardness is β'-phase,and it is suggested that solution treated at 530℃,aging at 160℃ for 8 hours is an ideal aging technique.
1993, 10(1): 51-56.
Abstract:
The changes and mechanism of internal dissipation of C/AL composite materials with different interfacial bonding strenglh after thermal cycling under external load are studied.It is fouad that the internal friction increases monotonically with the cycling numbers for C/L2 with relatively poor inierfzcial bornding,and this is mainly due to the local interfacial debonding.whereas,there is a peak at the curve of internal friction versus cycling numbers for C/LD2 wieh strong interfacial bonding,and this is mainly attributed to the break away of the dislocations.
The changes and mechanism of internal dissipation of C/AL composite materials with different interfacial bonding strenglh after thermal cycling under external load are studied.It is fouad that the internal friction increases monotonically with the cycling numbers for C/L2 with relatively poor inierfzcial bornding,and this is mainly due to the local interfacial debonding.whereas,there is a peak at the curve of internal friction versus cycling numbers for C/LD2 wieh strong interfacial bonding,and this is mainly attributed to the break away of the dislocations.
FABRICATION OF CARBON/ALUMINIUM PREFORM WIRES USING K2ZrF6 SOLUTION TO TREAT SiC COATED CARBON FIBER
1993, 10(1): 57-63.
Abstract:
Carbon fiber/aluminium preform wires were fabricated by the liquid metal infiltration method after carbon fiber were coated with SiCard treated with K2ZrFe6 solution.The strengths of the wires were about 70% of the strength calculated according to the "rule of mixture".The strength of preform wire with fiber volume fraction of 54% was about 1200 MPa.The SEM fractography of preform wire showed that the interfacial state was adequate.Through x-ray diffraction analyse of the reaction product of SiC,K2ZrF6 and Al at high temperature,it can be coneluded that the improvement of wetting ability between carbon fiber and aluminium was resulted from the active reaction of K2ZrF6,aluminium and SiC.
Carbon fiber/aluminium preform wires were fabricated by the liquid metal infiltration method after carbon fiber were coated with SiCard treated with K2ZrFe6 solution.The strengths of the wires were about 70% of the strength calculated according to the "rule of mixture".The strength of preform wire with fiber volume fraction of 54% was about 1200 MPa.The SEM fractography of preform wire showed that the interfacial state was adequate.Through x-ray diffraction analyse of the reaction product of SiC,K2ZrF6 and Al at high temperature,it can be coneluded that the improvement of wetting ability between carbon fiber and aluminium was resulted from the active reaction of K2ZrF6,aluminium and SiC.
1993, 10(1): 65-69.
Abstract:
Composite plate and shell with rubber Liner can simulate filament wound pressure vessels of the aircraft.The non-destructive testing for composite structure by using the stress wave technique is given in This paper.Using tliis method,defects between liner and winding layers as well as between liner layers have been inspected,the amplitude-frequency curves of the damaged reginos have been drawn,and the distribution of the defective regions between rubber liners is determined successfully.Finally,a proportionally reduced cylindrical case of a certain type of the roclket motor is practically inspected and a satisfied results is presented.
Composite plate and shell with rubber Liner can simulate filament wound pressure vessels of the aircraft.The non-destructive testing for composite structure by using the stress wave technique is given in This paper.Using tliis method,defects between liner and winding layers as well as between liner layers have been inspected,the amplitude-frequency curves of the damaged reginos have been drawn,and the distribution of the defective regions between rubber liners is determined successfully.Finally,a proportionally reduced cylindrical case of a certain type of the roclket motor is practically inspected and a satisfied results is presented.
1993, 10(1): 71-75.
Abstract:
Based on the quasi-parametric quadratic programming method and discontinuous linear elastic constitutive law model,this paper constitutes the micro-mechanics model of failure process at the fiber-matrix interface and does numerical analysis by finite element.The calculated results show an agreement with that of experiment.
Based on the quasi-parametric quadratic programming method and discontinuous linear elastic constitutive law model,this paper constitutes the micro-mechanics model of failure process at the fiber-matrix interface and does numerical analysis by finite element.The calculated results show an agreement with that of experiment.
1993, 10(1): 77-84.
Abstract:
Based on the micro-structure of materials in a tire,a 3D analysis model is presented in this paper.Geometrically nonlinear behavior resulted from large displacement,physically nonlinear behavior and bi-modulus of materials of various parts of the tire are considered.For changeable contact field with road,a parameter is used to improve the accuracy of hypothetical contact field.The incandescent Light Spectra Technique is used to measuer the surface displacement field of the tire,a comparison of theoretical and experimental results show a good agreement.
Based on the micro-structure of materials in a tire,a 3D analysis model is presented in this paper.Geometrically nonlinear behavior resulted from large displacement,physically nonlinear behavior and bi-modulus of materials of various parts of the tire are considered.For changeable contact field with road,a parameter is used to improve the accuracy of hypothetical contact field.The incandescent Light Spectra Technique is used to measuer the surface displacement field of the tire,a comparison of theoretical and experimental results show a good agreement.
1993, 10(1): 85-89.
Abstract:
Computer-simulation technique was used in the present study to probe the effect of interfacial bonding strength on the tensile fracture behavior of a metal-matrix composite by improving the as-verified computer program simulating the fracture process of the composite.The results show that,under various matrix strength levels,there exists an identical transition in the fracture mode of the composite from the cumulative to the non-cumulative and an increase in the fracture strength,as the interfacial bond strengthen.This trend becomes more sensitive when the strength distribution of the fibre turns wide.
Computer-simulation technique was used in the present study to probe the effect of interfacial bonding strength on the tensile fracture behavior of a metal-matrix composite by improving the as-verified computer program simulating the fracture process of the composite.The results show that,under various matrix strength levels,there exists an identical transition in the fracture mode of the composite from the cumulative to the non-cumulative and an increase in the fracture strength,as the interfacial bond strengthen.This trend becomes more sensitive when the strength distribution of the fibre turns wide.
1993, 10(1): 91-96.
Abstract:
In this paper,the behavior of buckling model of simply-supported orthotropic rectangular plate under biaxial loads is studied on the basis of the analytical solution.The law of buckling models in relation to loads is presented.
In this paper,the behavior of buckling model of simply-supported orthotropic rectangular plate under biaxial loads is studied on the basis of the analytical solution.The law of buckling models in relation to loads is presented.
1993, 10(1): 97-102.
Abstract:
The constitutive equations of composite materials have been obtained in the first part of this paper.Based on the previous study, the modified form of constitutive equation of creep deformation is given in this part.The strain in two stages of creep and recovery are experimentally recorded,which is used to determine the parameters of the constitutive equation,In view of the complexity of the nonlinear equation,this paper proposed a method to determine the parameters,in which the least-square-error method is used in conjunction with the discreteness of variables.Then the theoretical formulas are modelled by data fitting and each kind of strains is separated.Finally,based on a few of available experimental data,the three parametric functions of stress in the constitutive relationship obtained.
The constitutive equations of composite materials have been obtained in the first part of this paper.Based on the previous study, the modified form of constitutive equation of creep deformation is given in this part.The strain in two stages of creep and recovery are experimentally recorded,which is used to determine the parameters of the constitutive equation,In view of the complexity of the nonlinear equation,this paper proposed a method to determine the parameters,in which the least-square-error method is used in conjunction with the discreteness of variables.Then the theoretical formulas are modelled by data fitting and each kind of strains is separated.Finally,based on a few of available experimental data,the three parametric functions of stress in the constitutive relationship obtained.
1993, 10(1): 103-108.
Abstract:
Fault diagnosis of composite structure is increasingly of great interests.It is attractive to diagnose damage by means of vibration theory and experimental technique.In this paper,a new Frequency Response Function (FRF)-Modal Energy diagnositic method is proposed for damage detection of composite laminated plates.The method chooses FRF,which is relative sensitive to the damage and can reflect structure dynamic charateristic,as the diagnostic parameter,and lead to concept of damped dissipative energy and calculates the distribution of generalized modal energy of undamaged plate defined in the paper.The relationship between the varition of FRF at different-orderd resonant peak after damage and the modal energy contribute in each element of undamaged plate in given mode is derived by the theory analyses and calculations.Then,the new method is obtanned to detect the small damaged element or area.An important conclusion of this method is that,in the case of small damage,the ratio of each order generalized modal energy contribution in an element or area is approximately equal to the ratio of change rate at each order FRF resonant peak of undamaged plate in the corresponding damaged element or area.Energy distribution diagrams are given for damage analyses.The results of illustrative examples and experiments show that the method proposed by the aushors is effective and feasible.
Fault diagnosis of composite structure is increasingly of great interests.It is attractive to diagnose damage by means of vibration theory and experimental technique.In this paper,a new Frequency Response Function (FRF)-Modal Energy diagnositic method is proposed for damage detection of composite laminated plates.The method chooses FRF,which is relative sensitive to the damage and can reflect structure dynamic charateristic,as the diagnostic parameter,and lead to concept of damped dissipative energy and calculates the distribution of generalized modal energy of undamaged plate defined in the paper.The relationship between the varition of FRF at different-orderd resonant peak after damage and the modal energy contribute in each element of undamaged plate in given mode is derived by the theory analyses and calculations.Then,the new method is obtanned to detect the small damaged element or area.An important conclusion of this method is that,in the case of small damage,the ratio of each order generalized modal energy contribution in an element or area is approximately equal to the ratio of change rate at each order FRF resonant peak of undamaged plate in the corresponding damaged element or area.Energy distribution diagrams are given for damage analyses.The results of illustrative examples and experiments show that the method proposed by the aushors is effective and feasible.
1993, 10(1): 109-119.
Abstract:
Based on the framework of Tandon and Weng,the elasto-plastic theory of an orthotropic composite reinforced with unidirectionally-elliptic aligned cylinders,and a transversely isotropic composite reinforced with two-dimentional randomly-oriented elliptic cylinders,is established.The secant moduli yield surfaces and the average stress concentration factory of the matrix are derived.It is shown that both the secant moduli and the yield surfaces are strongly influenced by the shape of fibers;ribbons are seen to be most effective in transversly isotropic composite.
Based on the framework of Tandon and Weng,the elasto-plastic theory of an orthotropic composite reinforced with unidirectionally-elliptic aligned cylinders,and a transversely isotropic composite reinforced with two-dimentional randomly-oriented elliptic cylinders,is established.The secant moduli yield surfaces and the average stress concentration factory of the matrix are derived.It is shown that both the secant moduli and the yield surfaces are strongly influenced by the shape of fibers;ribbons are seen to be most effective in transversly isotropic composite.
