1985 Vol. 2, No. 4
1985, 2(4): 1-Ⅰ.
Abstract:
The chemical reaction occured between the surfaces of silica,as a model of glass and silanes-H2O system (or silanes-CCl4 system),has begin directly detected by chromatography and Fourier Transform Infrared Spectra.This strongly proves the existence of chemical reaction on the interface between these two phases,that is to say,the interfacial structure bonded by chemical bonds.From experimental results results it can be infeaed that the -Si-O-Si bond,IR absorbing peak 1056-1063 cm-1,appears by the by the homo-polycondensation reaction of silane itself.Then,the -Si-O-Si bond,IR absorbing peak 1105-1120 cm-1,appears by the coolycon densation reaction detween silane and the fumed SiO2.
The chemical reaction occured between the surfaces of silica,as a model of glass and silanes-H2O system (or silanes-CCl4 system),has begin directly detected by chromatography and Fourier Transform Infrared Spectra.This strongly proves the existence of chemical reaction on the interface between these two phases,that is to say,the interfacial structure bonded by chemical bonds.From experimental results results it can be infeaed that the -Si-O-Si bond,IR absorbing peak 1056-1063 cm-1,appears by the by the homo-polycondensation reaction of silane itself.Then,the -Si-O-Si bond,IR absorbing peak 1105-1120 cm-1,appears by the coolycon densation reaction detween silane and the fumed SiO2.
1985, 2(4): 9-Ⅱ.
Abstract:
The nonequlibrium thermodynamic fluctuation theory has been used to predict the cure behavior of epoxy-imidazole-SiO2 system at various temperatures and various SiO2 filler loadings.There exists good agreement between the theoretical predictions and experimental reaults obtained by the dynamic torsional vibration method.It has been shown that the activation energy of cure reaction almost remained a constant value of △H=76.6×103J/mol with various.SiO2 filler loadngs,but SiO2 filler has a cempex effect on the rate of the cure reaction.
The nonequlibrium thermodynamic fluctuation theory has been used to predict the cure behavior of epoxy-imidazole-SiO2 system at various temperatures and various SiO2 filler loadings.There exists good agreement between the theoretical predictions and experimental reaults obtained by the dynamic torsional vibration method.It has been shown that the activation energy of cure reaction almost remained a constant value of △H=76.6×103J/mol with various.SiO2 filler loadngs,but SiO2 filler has a cempex effect on the rate of the cure reaction.
1985, 2(4): 15-Ⅱ.
Abstract:
The basic concepts of anisotropic damage mechanics for composites are explained in detail.Both Lcmaittre's model based on the hypothesis of strain equivalence and Coderbois' model on elastic energy indentification arc introduced and discussed herein.
The basic concepts of anisotropic damage mechanics for composites are explained in detail.Both Lcmaittre's model based on the hypothesis of strain equivalence and Coderbois' model on elastic energy indentification arc introduced and discussed herein.
1985, 2(4): 23-Ⅲ.
Abstract:
The application of the anisolropic damage mechanics to composites is explore in this paper.The outline of the damage tests for laminated composites and some measurement methods are briefly presented.The experimental results of three kinds of laminates under uniaxial tension show the damage energy release rate under uniaxial tension,Y2,based on Lemaitre's hypothesis of strain equivalence can be used to describe the mechanical state of damaged laminates.The damage evolution law can be represented by the simple function form of Y2=α(σ/σc)β,where α and β are coefficients which are inedpendent of the shape and size of the initial defect in laminates and can be experimentally determined.The critical damage energy release rate under uniaxial tension,Y2c,represents the capscity against the damage evolution in the laminates and it is independent o:the shape and sizc of initial defects in laminates.
The application of the anisolropic damage mechanics to composites is explore in this paper.The outline of the damage tests for laminated composites and some measurement methods are briefly presented.The experimental results of three kinds of laminates under uniaxial tension show the damage energy release rate under uniaxial tension,Y2,based on Lemaitre's hypothesis of strain equivalence can be used to describe the mechanical state of damaged laminates.The damage evolution law can be represented by the simple function form of Y2=α(σ/σc)β,where α and β are coefficients which are inedpendent of the shape and size of the initial defect in laminates and can be experimentally determined.The critical damage energy release rate under uniaxial tension,Y2c,represents the capscity against the damage evolution in the laminates and it is independent o:the shape and sizc of initial defects in laminates.
1985, 2(4): 30-Ⅳ.
Abstract:
In this study samples of a composite material were obtained by compossive infiltration of Aluminum-Carbon proformed wires with LY-12 aluminum alloy.Morphology of C/Al composite after high temperature treatments was examined under optical and ShAI.The quantities of the carbide in these samples were determined by gas mass spectrometer.Reaction product was identified by x-ray diffraction.This paper reviewed the behaviour of the C/Al proformed wires in the aluminum melt under high temperature.The interface reaction between carbon and aluminum occures at high temperaure,forming britle layer of aluminum carbide,and it depends on the condition in which it was produced and used.The higher the temperature and the longer the time of the holdings the more obvious the reaction.It is important choosing suitable forming tech nology.It is also available to choose coating on fiber with suitable construction to prevent from interface reaction,and the interface waa influenced by sorts of the fiber and composition of the matrix.
In this study samples of a composite material were obtained by compossive infiltration of Aluminum-Carbon proformed wires with LY-12 aluminum alloy.Morphology of C/Al composite after high temperature treatments was examined under optical and ShAI.The quantities of the carbide in these samples were determined by gas mass spectrometer.Reaction product was identified by x-ray diffraction.This paper reviewed the behaviour of the C/Al proformed wires in the aluminum melt under high temperature.The interface reaction between carbon and aluminum occures at high temperaure,forming britle layer of aluminum carbide,and it depends on the condition in which it was produced and used.The higher the temperature and the longer the time of the holdings the more obvious the reaction.It is important choosing suitable forming tech nology.It is also available to choose coating on fiber with suitable construction to prevent from interface reaction,and the interface waa influenced by sorts of the fiber and composition of the matrix.
1985, 2(4): 35-Ⅳ.
Abstract:
The change of the tensile strength of the C/Al composite wires and the content of the aluminum carbide in the interfaces have been studied.The authors note the strength of compolite wires was damaged after long period heal-treatment at 495℃ and was damaged remarkably above 540℃,and the content of the alumimum carbide increases with increaasing the tempatature and the time of treament.
The change of the tensile strength of the C/Al composite wires and the content of the aluminum carbide in the interfaces have been studied.The authors note the strength of compolite wires was damaged after long period heal-treatment at 495℃ and was damaged remarkably above 540℃,and the content of the alumimum carbide increases with increaasing the tempatature and the time of treament.
1985, 2(4): 40-Ⅴ.
Abstract:
Failure criteria for isotropic and anisotropic materials are briefly reviewed.They serve as a background for the criterion presented below.Based on the work of Reference [1]and [5],a failure theory which is predominted by matrix and interface failure is presented to predict the failure of composite materials under complex stress state.The criterion formula greatly depends on the failure characteristics of the matrix,while coefficients test of the formula are entirely determined by the properties and volume fraction of the components and the adhesion of interface.The theory also exposes how these parameters influence the failure of the materials,which is significant for material and structure design of composites. The theoretical predictions of off-axis tensile strength agree well with experimental results.
Failure criteria for isotropic and anisotropic materials are briefly reviewed.They serve as a background for the criterion presented below.Based on the work of Reference [1]and [5],a failure theory which is predominted by matrix and interface failure is presented to predict the failure of composite materials under complex stress state.The criterion formula greatly depends on the failure characteristics of the matrix,while coefficients test of the formula are entirely determined by the properties and volume fraction of the components and the adhesion of interface.The theory also exposes how these parameters influence the failure of the materials,which is significant for material and structure design of composites. The theoretical predictions of off-axis tensile strength agree well with experimental results.
1985, 2(4): 49-Ⅴ.
Abstract:
In this work the mechanism of the solid-state polycondensation of crystalline nylon-1010 salt (sebaeodiamonium sebate) with short carbon fiber composites and effects of the chemical and physical interface Letween the fiber and matrix have been studied by the use of a number of techniques including determination of conversion rate and of molecular weight,IR,polarized light microscopy and SEM.The experimental results indicated that during the solid-state polycondensation the invert gas N2 flow,reaction-temperature and time,amount and surface characteristics of carbon fiber used remarkably influence the conversion rate and molecular weight of the formed nascent nylon 1010 matrix.It was found that some interfacial effects such as fiber surface nucleating tire crystallization and catalytic effect for the "in situ solid-state polycondensation" of nylon1010 salt existed.The interfacial effects of carbon fiber on the expitaxial crystallization of the formed nascent nylon-1010 have been discussed.
In this work the mechanism of the solid-state polycondensation of crystalline nylon-1010 salt (sebaeodiamonium sebate) with short carbon fiber composites and effects of the chemical and physical interface Letween the fiber and matrix have been studied by the use of a number of techniques including determination of conversion rate and of molecular weight,IR,polarized light microscopy and SEM.The experimental results indicated that during the solid-state polycondensation the invert gas N2 flow,reaction-temperature and time,amount and surface characteristics of carbon fiber used remarkably influence the conversion rate and molecular weight of the formed nascent nylon 1010 matrix.It was found that some interfacial effects such as fiber surface nucleating tire crystallization and catalytic effect for the "in situ solid-state polycondensation" of nylon1010 salt existed.The interfacial effects of carbon fiber on the expitaxial crystallization of the formed nascent nylon-1010 have been discussed.
1985, 2(4): 57-Ⅵ.
Abstract:
This peper presents the analysis of composite plates arid cylindrical shells with holes by a high precision triangular finite element.The analysis includes general static problem,stability anal vibration of the structures.Fundamental formulas have been berived and a method generating automatically the element matrices is also presented.The vibration characteristics of composite cylindrical panels with a circular hole is mainly analyzed.Examples show that good computtational precison exits.
This peper presents the analysis of composite plates arid cylindrical shells with holes by a high precision triangular finite element.The analysis includes general static problem,stability anal vibration of the structures.Fundamental formulas have been berived and a method generating automatically the element matrices is also presented.The vibration characteristics of composite cylindrical panels with a circular hole is mainly analyzed.Examples show that good computtational precison exits.
1985, 2(4): 64-Ⅶ.
Abstract:
Recently,the curing process,which proved to have a heavy influence on the qualit of epoxy-based composites,has been studied by using a lot of methods.One of them,they model method is a newlydeveloped one.The paper summarized the curing models used at present which involed the thermo-chemical model,the flow model,the void model and the sterss model.There are a lot of factors to influence the curing process of the composites.A ccording to G.S.Springei/s and H.C.Halpin's works,however,the influence of each factor could be.
Recently,the curing process,which proved to have a heavy influence on the qualit of epoxy-based composites,has been studied by using a lot of methods.One of them,they model method is a newlydeveloped one.The paper summarized the curing models used at present which involed the thermo-chemical model,the flow model,the void model and the sterss model.There are a lot of factors to influence the curing process of the composites.A ccording to G.S.Springei/s and H.C.Halpin's works,however,the influence of each factor could be.
1985, 2(4): 69-73.
Abstract:
The paper describes the inspection principle of soft X-ray machine having a Be-window and a fine focal spot of 0.4×0.4mm.The performances of some types of films home-made have been compared with those made in other countries.And it also introduces the selections of the suitable radiographying para meters,including the exposure-chart and the relative curve between the material thickness under inspected and the film-densities used,and the types of defects that can be found.Using penetrant enhanced X-ray radiography,the delamtnations around the holes drilled in CFRP are detected.
The paper describes the inspection principle of soft X-ray machine having a Be-window and a fine focal spot of 0.4×0.4mm.The performances of some types of films home-made have been compared with those made in other countries.And it also introduces the selections of the suitable radiographying para meters,including the exposure-chart and the relative curve between the material thickness under inspected and the film-densities used,and the types of defects that can be found.Using penetrant enhanced X-ray radiography,the delamtnations around the holes drilled in CFRP are detected.
