1994 Vol. 11, No. 2
1994, 11(2): 1-6.
Abstract:
Laminated beam theory is the basis of mechanical behavior analyses of composite laminated beams and stiffened laminated structures. The first-order shear deformation theories of a transversely laminated beam a longitudinally laminated beam and a combined beam are developed based on the hlindl in hypothesis.The coupled effects between. variables are included in the present theories.The exact stiffness can be obtained by using the stiffness expressions developed.For generality,thermal behavior is considered in the formulation.
Laminated beam theory is the basis of mechanical behavior analyses of composite laminated beams and stiffened laminated structures. The first-order shear deformation theories of a transversely laminated beam a longitudinally laminated beam and a combined beam are developed based on the hlindl in hypothesis.The coupled effects between. variables are included in the present theories.The exact stiffness can be obtained by using the stiffness expressions developed.For generality,thermal behavior is considered in the formulation.
1994, 11(2): 7-13.
Abstract:
Abstract In this paper,FE thermo-stiffness and thermo-load of temperature field are given for 3-D temperature problems with inner thermogenesis. Taking account of the complexity of tire structures,both pentahedron elemeat and hexahedron element are used to analyze the temperature field of a radial tire,and an infrared image device is used to m easure the surface temperature of the tire. A comparison of the theoretical calculation with experirnert shows that the calculation is satisfactory.
Abstract In this paper,FE thermo-stiffness and thermo-load of temperature field are given for 3-D temperature problems with inner thermogenesis. Taking account of the complexity of tire structures,both pentahedron elemeat and hexahedron element are used to analyze the temperature field of a radial tire,and an infrared image device is used to m easure the surface temperature of the tire. A comparison of the theoretical calculation with experirnert shows that the calculation is satisfactory.
1994, 11(2): 14-22.
Abstract:
The aerial tensile properties and fracture mechanism of in-situ composite Al11La3/Al have been investi,gate;l in the temperature range of 293-693ph.The result is that:the tensil.strength reaches 260 MPa at the norma temperature and:365 MPa at 693K for the alloy under the condition of directioral solidification(G=700K/cm,R=11.1 μm/s).With the study on the tensile process and the fracture morphology,the in-situ composite Al11La3/Al has the same axial tensile fracture mechanism in the temperature range of 293-693K.The fracture of fiber phase Al11La3 the critical factor for the fracture of the composite.The fracture model of tensile test is,elastic deformation,cracks neucleation,interface separation cracka propagation and macrofracture.
The aerial tensile properties and fracture mechanism of in-situ composite Al11La3/Al have been investi,gate;l in the temperature range of 293-693ph.The result is that:the tensil.strength reaches 260 MPa at the norma temperature and:365 MPa at 693K for the alloy under the condition of directioral solidification(G=700K/cm,R=11.1 μm/s).With the study on the tensile process and the fracture morphology,the in-situ composite Al11La3/Al has the same axial tensile fracture mechanism in the temperature range of 293-693K.The fracture of fiber phase Al11La3 the critical factor for the fracture of the composite.The fracture model of tensile test is,elastic deformation,cracks neucleation,interface separation cracka propagation and macrofracture.
1994, 11(2): 23-27.
Abstract:
Owing to the need of certain application a type of composite mataial is made not only to be a structural material but also to be provided with multiple functions,such as ablation resistance,impact resistance, thermal insulation etc.This type of composite material might be called "Multifunction Structure Composite Material" which should be designed by means of respective multilayers,so that different layers have different functions.The possibility to devel叩a_nd apply multifunction structure tomposits materials is provided by 3-D braid technologies,because of the integrated and special-shaped 3-D braid technologies to make different layers interbraided.The performance of 3-D braided composites and 3-D braid technoloaie.;manufacturinj multifunction structure composite materials are discribed in this paper.
Owing to the need of certain application a type of composite mataial is made not only to be a structural material but also to be provided with multiple functions,such as ablation resistance,impact resistance, thermal insulation etc.This type of composite material might be called "Multifunction Structure Composite Material" which should be designed by means of respective multilayers,so that different layers have different functions.The possibility to devel叩a_nd apply multifunction structure tomposits materials is provided by 3-D braid technologies,because of the integrated and special-shaped 3-D braid technologies to make different layers interbraided.The performance of 3-D braided composites and 3-D braid technoloaie.;manufacturinj multifunction structure composite materials are discribed in this paper.
1994, 11(2): 29-38.
Abstract:
Using the Simple Higher-order Theory,the bending deflection of thick cross-ply rectangular laminates of bimodulus composite materials is considered in this pager. The present solutions are more accurate when compared with the first-oder theory.
Using the Simple Higher-order Theory,the bending deflection of thick cross-ply rectangular laminates of bimodulus composite materials is considered in this pager. The present solutions are more accurate when compared with the first-oder theory.
1994, 11(2): 39-42.
Abstract:
A study was conducted to the tensile fracture behavior of graphite composite laminates with thermoplastic matrix. The results show that undamaged ultimate tensile strengths and damaged fracture stress of the laminates with thermoplastic matrix (PEEK) are higher than that of the ores with epoxy matrix for the same configuration,and the difference between them becomes greater with the increacement of the percentage of 0°-layers,and the notch sensitivity is lower and the fracture toughness is higher for graphite/hermopIastic(AS4/PEEK),as compared with the graphite/epoxy (AS4/3501)laminates.
A study was conducted to the tensile fracture behavior of graphite composite laminates with thermoplastic matrix. The results show that undamaged ultimate tensile strengths and damaged fracture stress of the laminates with thermoplastic matrix (PEEK) are higher than that of the ores with epoxy matrix for the same configuration,and the difference between them becomes greater with the increacement of the percentage of 0°-layers,and the notch sensitivity is lower and the fracture toughness is higher for graphite/hermopIastic(AS4/PEEK),as compared with the graphite/epoxy (AS4/3501)laminates.
1994, 11(2): 43-47.
Abstract:
In this paper,the vibration of composite materials orthotropic laminated plates have been analyzed by the Boundary Element Method.In order to overcome the difficulty in finding the fundamental solution in Boundary Element Method to the vibration of orthotropic laminated plates approximate fundamental solutions of the Fourier series form is used.The computed examples are shown that the method is reliable and efficient.
In this paper,the vibration of composite materials orthotropic laminated plates have been analyzed by the Boundary Element Method.In order to overcome the difficulty in finding the fundamental solution in Boundary Element Method to the vibration of orthotropic laminated plates approximate fundamental solutions of the Fourier series form is used.The computed examples are shown that the method is reliable and efficient.
1994, 11(2): 49-55.
Abstract:
Abstract Tensile and bending properties of blends of two thermotropic liquid crystalline polymers with a polycaroonate and a polyethersulfone have beer. investigated,respectively.The injection molded test bars of these blends exhibite great stiffness due to in-situ formed. fibers of the disperse TLCP phase in matrix duriIg the melt blending and mold filling,ar.d the moduli of the TLCP fibers in the matrix which in the experiment were obtained are substantially higher than those presently known from polymer literature. The processing conditions such as melt temperature and injection speed have a striking influence upon the mechanical properties.Because of immiscibility between TLCP's and matrix polymers,measured by FTIR,there is only weak adhesion between these components,so that the strengths of the blends was found to be similar to that of the unblended matrixes,and a reinforcement was not always observed.The injection molded bars show also great hardness in the cross section,but there is a non-uniform distribution.
Abstract Tensile and bending properties of blends of two thermotropic liquid crystalline polymers with a polycaroonate and a polyethersulfone have beer. investigated,respectively.The injection molded test bars of these blends exhibite great stiffness due to in-situ formed. fibers of the disperse TLCP phase in matrix duriIg the melt blending and mold filling,ar.d the moduli of the TLCP fibers in the matrix which in the experiment were obtained are substantially higher than those presently known from polymer literature. The processing conditions such as melt temperature and injection speed have a striking influence upon the mechanical properties.Because of immiscibility between TLCP's and matrix polymers,measured by FTIR,there is only weak adhesion between these components,so that the strengths of the blends was found to be similar to that of the unblended matrixes,and a reinforcement was not always observed.The injection molded bars show also great hardness in the cross section,but there is a non-uniform distribution.
1994, 11(2): 57-62.
Abstract:
Abstract A series of PCD (polycrystalline diamond) samples with Si binder are produced at various high temperatures (1100℃一1650℃)and ultrahigh pressures (4.5-6.25GPa).Their structures and wear resistance are investigated by x-ray diffraction analysis, SEM observation and abrasion test.The resin is are shown that there are three zones on the P-T graph corresponding to various PCD structure.G-ratio of PCD which consists of diamond and SiC is optimum.Si is retained at lower pressure and lower temperature and diamond graphitization occurs st lower pressure and higher temperature.Thus,the wear resistance of these PCD is lower.The pressure and temperature conditions far PCD consisting of diamond and SiC are discussed.
Abstract A series of PCD (polycrystalline diamond) samples with Si binder are produced at various high temperatures (1100℃一1650℃)and ultrahigh pressures (4.5-6.25GPa).Their structures and wear resistance are investigated by x-ray diffraction analysis, SEM observation and abrasion test.The resin is are shown that there are three zones on the P-T graph corresponding to various PCD structure.G-ratio of PCD which consists of diamond and SiC is optimum.Si is retained at lower pressure and lower temperature and diamond graphitization occurs st lower pressure and higher temperature.Thus,the wear resistance of these PCD is lower.The pressure and temperature conditions far PCD consisting of diamond and SiC are discussed.
1994, 11(2): 63-68.
Abstract:
An investigation of multiple crackiang in brittle reaction zone at interfaces of unidirectional composites with longitudinal tensile has been made by using three concentric circular cylinder model,and sheat-lay onolysis proposed by Cox.Both the cases of strongly and weakly bonded fiber/brittle reaction zone interfaces were considered.The crack sFacing was found to decrease with the increase of the brittle reaction zone thickness and increase with the decrease of the interface shear strength.
An investigation of multiple crackiang in brittle reaction zone at interfaces of unidirectional composites with longitudinal tensile has been made by using three concentric circular cylinder model,and sheat-lay onolysis proposed by Cox.Both the cases of strongly and weakly bonded fiber/brittle reaction zone interfaces were considered.The crack sFacing was found to decrease with the increase of the brittle reaction zone thickness and increase with the decrease of the interface shear strength.
1994, 11(2): 69-74.
Abstract:
The surface energetics of Kevlar-49 and glass fiber were studied by wicking test.The affecting of liquid quantity adhering on thebundle end was discussed. A data treatment method was proposed as well. The surface free energy of Kevlar-49 was determined as 37 mJ/m2,with the dispersive component of 28 mJ/m2 and the polo:component of 9 mJ/m2.
The surface energetics of Kevlar-49 and glass fiber were studied by wicking test.The affecting of liquid quantity adhering on thebundle end was discussed. A data treatment method was proposed as well. The surface free energy of Kevlar-49 was determined as 37 mJ/m2,with the dispersive component of 28 mJ/m2 and the polo:component of 9 mJ/m2.
1994, 11(2): 69-79.
Abstract:
This paper discuses interaction,micro-}tructure and mechanical properties on glass fiber reinforced polymer/floation bead/cement composlte.Using SEMI,XRD,TG,DTA and mechanical properties measurement it is found that the flexible strength of composite is greatly increased by reinforcement of glass fiber and good adhesions,toughness of polymer.At the same time,the polymer latexes can affect the hydration of cement, reduce the content of calcium hydroxide in the composite,retard the corrosion of glass fiber and improve the durability of the composite.
This paper discuses interaction,micro-}tructure and mechanical properties on glass fiber reinforced polymer/floation bead/cement composlte.Using SEMI,XRD,TG,DTA and mechanical properties measurement it is found that the flexible strength of composite is greatly increased by reinforcement of glass fiber and good adhesions,toughness of polymer.At the same time,the polymer latexes can affect the hydration of cement, reduce the content of calcium hydroxide in the composite,retard the corrosion of glass fiber and improve the durability of the composite.
1994, 11(2): 81-89.
Abstract:
A mechanical model of the interfacial transcrystallinity in the composite of polyetheretherketone (PEEK) reinforced with carbon fiber was obtamed on the basis of its structural ch ara}teristic.Young's modulus of the transcrystallinity in the direction perpendicular to the fibre ov which it grows was found to be greater than that of the bulk opherulite,and depend on the lamellar structure in the transcrystallinity.It incre ases with the increasing of lamellzr length or thickness,but decrease;with the increasing of the lamellar width.The reason was discussed,and the result was verified with experiments.
A mechanical model of the interfacial transcrystallinity in the composite of polyetheretherketone (PEEK) reinforced with carbon fiber was obtamed on the basis of its structural ch ara}teristic.Young's modulus of the transcrystallinity in the direction perpendicular to the fibre ov which it grows was found to be greater than that of the bulk opherulite,and depend on the lamellar structure in the transcrystallinity.It incre ases with the increasing of lamellzr length or thickness,but decrease;with the increasing of the lamellar width.The reason was discussed,and the result was verified with experiments.
1994, 11(2): 91-96.
Abstract:
Effect of composition and raw mateials paricle size on tombustion temperature and propagating rate in the Self-propagating High-temperature Synthesis of TiB2-xAl composite system was theoretically and experimentally analyzed.With the variation of Al content,the change of tested combustion temperature tends to be the same as that of calculated ones.Combustion propagating rate shows the maximum value when Al content is alout 12 vol% because the liquid metal provides better conditions for mass diffusion and transfer but consumes relatively little energy. Because Al phase does not take part in the direct reaction as that of Ti and B partitles in this synthesis,variations of the particle size of Ti and B have much stronger influence on the SHS process than that of A1.
Effect of composition and raw mateials paricle size on tombustion temperature and propagating rate in the Self-propagating High-temperature Synthesis of TiB2-xAl composite system was theoretically and experimentally analyzed.With the variation of Al content,the change of tested combustion temperature tends to be the same as that of calculated ones.Combustion propagating rate shows the maximum value when Al content is alout 12 vol% because the liquid metal provides better conditions for mass diffusion and transfer but consumes relatively little energy. Because Al phase does not take part in the direct reaction as that of Ti and B partitles in this synthesis,variations of the particle size of Ti and B have much stronger influence on the SHS process than that of A1.
1994, 11(2): 97-105.
Abstract:
The mechanical properties the crystallization of matrix of glass fiber-reinforeed PP aml their dependence on the interfacial, dhesion have been studied by using seamning electron microscope,infrarel spectrometer,material universal testing machine,polarizing microscope and DSC. etc.The results show that in the compounding process of glass fiber and PP,the added interfacal, reactive agents and the formed product from their grafting with PP cai react with the multilayer silicane coupling agent on the surface of glass fiber, and obviously increase the interfacial phase module,the interfacial bond strength and mechanical properties of the compocite.PP,Meanwhile,it was found that the produced interfacial stress from the contraction of the matix in injection molding can strain-induce the crystallization of matrix and leads to obvious change about the morphology and the crystallinity of matrix,and that the interfacial band strength is an im portant factor of producing the straininduced crystallization and controlling the strain-induced crystallization as well as controlling the multiphase crystallization.
The mechanical properties the crystallization of matrix of glass fiber-reinforeed PP aml their dependence on the interfacial, dhesion have been studied by using seamning electron microscope,infrarel spectrometer,material universal testing machine,polarizing microscope and DSC. etc.The results show that in the compounding process of glass fiber and PP,the added interfacal, reactive agents and the formed product from their grafting with PP cai react with the multilayer silicane coupling agent on the surface of glass fiber, and obviously increase the interfacial phase module,the interfacial bond strength and mechanical properties of the compocite.PP,Meanwhile,it was found that the produced interfacial stress from the contraction of the matix in injection molding can strain-induce the crystallization of matrix and leads to obvious change about the morphology and the crystallinity of matrix,and that the interfacial band strength is an im portant factor of producing the straininduced crystallization and controlling the strain-induced crystallization as well as controlling the multiphase crystallization.
1994, 11(2): 107-111.
Abstract:
Carbon/carbon(C/C) composites can be oxidized in air above 400℃.The crack problem can't be solved because of the different thermal expansion coefficient between coating and matrix.Increasing the oxidation resistance of coating and the C/C itself at the same time is an effective method.In this paper,ZrO2,SiO2,SiC,B4C powder were added into the C/C matrix and the effect of additives on the oxidation resistance was analysed. The results show that the additives can increase the C/C oxidation resistance greatly and decrease the burning rate effectively.The method of matrix modification is effective.
Carbon/carbon(C/C) composites can be oxidized in air above 400℃.The crack problem can't be solved because of the different thermal expansion coefficient between coating and matrix.Increasing the oxidation resistance of coating and the C/C itself at the same time is an effective method.In this paper,ZrO2,SiO2,SiC,B4C powder were added into the C/C matrix and the effect of additives on the oxidation resistance was analysed. The results show that the additives can increase the C/C oxidation resistance greatly and decrease the burning rate effectively.The method of matrix modification is effective.
