1998 Vol. 15, No. 4
1998, 15(4): 1-5.
Abstract:
The traditional methods of surface treatment include gaseous, acid, solution, plasma, and electrolytic oxidation. 60 Coγ ray irradation was newly used to increase the surface concentration of oxygen functionalities. The effect of such treatment upon fiber surface mechanical properties, chemistry, reactivity and roughness has been studied. X ray photoelectron spectroscope, electron microscope, Raman shift, and X ray diffraction were used to determine elemental compositional changes in fiber surface caused by irradiation. It was found that irradiation treatment improved the tensile strength, modulus, and fracture strain of carbon fiber, and surface oxygen is found in the distribution during irradiation dose 1×102～1×103Gy; irradiation process could change surface chemical constituents, leading to the promotion of surface activities. Maximum interlaminar shear strength of carbon fiber(dose 1×103Gy)/epoxy corresponds to an increase of 31%.
The traditional methods of surface treatment include gaseous, acid, solution, plasma, and electrolytic oxidation. 60 Coγ ray irradation was newly used to increase the surface concentration of oxygen functionalities. The effect of such treatment upon fiber surface mechanical properties, chemistry, reactivity and roughness has been studied. X ray photoelectron spectroscope, electron microscope, Raman shift, and X ray diffraction were used to determine elemental compositional changes in fiber surface caused by irradiation. It was found that irradiation treatment improved the tensile strength, modulus, and fracture strain of carbon fiber, and surface oxygen is found in the distribution during irradiation dose 1×102～1×103Gy; irradiation process could change surface chemical constituents, leading to the promotion of surface activities. Maximum interlaminar shear strength of carbon fiber(dose 1×103Gy)/epoxy corresponds to an increase of 31%.
1998, 15(4): 6-13.
Abstract:
In this paper, the no asbestos fiber reinforced cork and rubber gasket material was made by the jute fiber instead of asbestos. The effects of the composition and manufacturing technology on the properties of the gasket were discussed in detail. The results show that fiber can improve the tensile strength, oil resistance, heat resistance and creep relaxation resistance of the sheet. And it was found that the main properties of the gasket material depend on aspect ratio, content of fiber, fibre matrix adhesion and manufacturing technology. The new material could be used in a wide range of industries as asbestos substitute.
In this paper, the no asbestos fiber reinforced cork and rubber gasket material was made by the jute fiber instead of asbestos. The effects of the composition and manufacturing technology on the properties of the gasket were discussed in detail. The results show that fiber can improve the tensile strength, oil resistance, heat resistance and creep relaxation resistance of the sheet. And it was found that the main properties of the gasket material depend on aspect ratio, content of fiber, fibre matrix adhesion and manufacturing technology. The new material could be used in a wide range of industries as asbestos substitute.
1998, 15(4): 14-19.
Abstract:
In this paper, the piezoelectric properties, dielectric properties, pyroelectric properties of some ceramic polymer composites and their applications are introduced. And the preparation process, electronic properties and potential applications of n SrTiO 3/p PAn heterojunction are also are reviewed.
In this paper, the piezoelectric properties, dielectric properties, pyroelectric properties of some ceramic polymer composites and their applications are introduced. And the preparation process, electronic properties and potential applications of n SrTiO 3/p PAn heterojunction are also are reviewed.
PREPARATION AND DIELECTRIC PROPERTIES OF THE FUNCTIONAL FINE COMPOSITE OF NANO PARTICLE BaTiO3/EPOXY
1998, 15(4): 20-23.
Abstract:
The nano particle BaTiO3/epoxy composite was prepared by fine composite process and the dielectric properties of the composite material were studied by changing the weight fraction of BaTiO3 in this paper.
The nano particle BaTiO3/epoxy composite was prepared by fine composite process and the dielectric properties of the composite material were studied by changing the weight fraction of BaTiO3 in this paper.
1998, 15(4): 24-27.
Abstract:
In this paper, a tetramaleicimide (TMI) synthesized with maleicanlydride and tetraniline group is introduced. TMI can solve in acetone. Little of TMI can solve in acetic alcohol ester. After curing at 280℃/1h, the decomposition temperature of TMI is 527℃. The TMI has good technological process and mechanics properties.
In this paper, a tetramaleicimide (TMI) synthesized with maleicanlydride and tetraniline group is introduced. TMI can solve in acetone. Little of TMI can solve in acetic alcohol ester. After curing at 280℃/1h, the decomposition temperature of TMI is 527℃. The TMI has good technological process and mechanics properties.
1998, 15(4): 28-32.
Abstract:
The water resistance of the magnesium oxychloride composite materials was studied with SEM, X ray diffraction analysis and the normal property test. Through the test of adding different modifiers, K 3(X·Y6) was selected as the best modifier. Its soft coefficient remains at 0.94 after the immersing in the water for three months. The modificatory mechanism was explored through modern techniques.
The water resistance of the magnesium oxychloride composite materials was studied with SEM, X ray diffraction analysis and the normal property test. Through the test of adding different modifiers, K 3(X·Y6) was selected as the best modifier. Its soft coefficient remains at 0.94 after the immersing in the water for three months. The modificatory mechanism was explored through modern techniques.
1998, 15(4): 33-37.
Abstract:
The mechanical properties and fractograph of short mullite fiber reinforced Al-4.5Cu composite fabricated by squeeze cast method were studied in this paper. The experimental results showed that the bending strength and elastic modulus of the composite were improved both with increasing of solidification rate. The fracture surface of the composite showed a character of the brittle cleavage fracture. When the solidification rate was higher, a few mullite fibers were drawn out in certain areas of the fracture surface, and they represented the higher bending strength. In all cases of the solidificating rates studied, a few tough nests on the fracture surface of the composite were also observed.
The mechanical properties and fractograph of short mullite fiber reinforced Al-4.5Cu composite fabricated by squeeze cast method were studied in this paper. The experimental results showed that the bending strength and elastic modulus of the composite were improved both with increasing of solidification rate. The fracture surface of the composite showed a character of the brittle cleavage fracture. When the solidification rate was higher, a few mullite fibers were drawn out in certain areas of the fracture surface, and they represented the higher bending strength. In all cases of the solidificating rates studied, a few tough nests on the fracture surface of the composite were also observed.
1998, 15(4): 38-42.
Abstract:
Electrical conductivity of the CF/Cu composites with different modes of CF orientation and distribution, prepared by hot pressing, was examined to be in order: unidirectional longitudinal>bidirectional>spiral>unidirectional transversal>random short fibers. The electrical conductivity of the CF/Cu composites decreases with the increase of the volume of carbon fiber.
Electrical conductivity of the CF/Cu composites with different modes of CF orientation and distribution, prepared by hot pressing, was examined to be in order: unidirectional longitudinal>bidirectional>spiral>unidirectional transversal>random short fibers. The electrical conductivity of the CF/Cu composites decreases with the increase of the volume of carbon fiber.
1998, 15(4): 43-47.
Abstract:
The interfacial reaction of liquid stirred cast SiCP and SiO2(P) reinforced Al4wt%Mg matrix composites was studied by means of analytical transmission electronic microscope. The results show that the fine MgO particles are formed on the surface of as received SiC particle and oxidized one. The quartz particles reacted with magnesium in matrix to form MgAl2O4. And the reaction mechanisms are explained respectively with the diffusion theory.
The interfacial reaction of liquid stirred cast SiCP and SiO2(P) reinforced Al4wt%Mg matrix composites was studied by means of analytical transmission electronic microscope. The results show that the fine MgO particles are formed on the surface of as received SiC particle and oxidized one. The quartz particles reacted with magnesium in matrix to form MgAl2O4. And the reaction mechanisms are explained respectively with the diffusion theory.
1998, 15(4): 48-52.
Abstract:
Fully dense Al2O3-Al3Ti-Al composites were in situ reaction processed by combining squeeze casting technique with combustion synthesis utilizing the reaction between TiO2 and pure Al. The in situ reaction formed spherical Al2O3 particles with a size of 0.1μm to 1μm are uniformly distributed in the matrix. The composites possess high flexural strength (410～490MPa) and elastic modulus (156～216GPa). With increasing content of Al in the composite, the bending strength begins to increase slightly and then decreases when the volume fraction of Al exceeds 40%. The elastic modulus of the composites decreases with increasing content of Al. The high flexural strength of the in situ composites is mainly attributed to the dispersion strengthening of fine Al2O3 particles and Al3Ti phase.
Fully dense Al2O3-Al3Ti-Al composites were in situ reaction processed by combining squeeze casting technique with combustion synthesis utilizing the reaction between TiO2 and pure Al. The in situ reaction formed spherical Al2O3 particles with a size of 0.1μm to 1μm are uniformly distributed in the matrix. The composites possess high flexural strength (410～490MPa) and elastic modulus (156～216GPa). With increasing content of Al in the composite, the bending strength begins to increase slightly and then decreases when the volume fraction of Al exceeds 40%. The elastic modulus of the composites decreases with increasing content of Al. The high flexural strength of the in situ composites is mainly attributed to the dispersion strengthening of fine Al2O3 particles and Al3Ti phase.
1998, 15(4): 53-58.
Abstract:
The CVD installation to obtain coating on ceramic particles was designed and made. The process of obtaining TiN coating on Al2O3 particles was investigated. The results show that the TiN coating can improve the infiltrating depth of the heat resistant steel liquid between Al2O3 particles, and the particles can be firmly sustained by the matrix. The fraction of Al2O3 particles in composite may be adjusted between 23%～57%.
The CVD installation to obtain coating on ceramic particles was designed and made. The process of obtaining TiN coating on Al2O3 particles was investigated. The results show that the TiN coating can improve the infiltrating depth of the heat resistant steel liquid between Al2O3 particles, and the particles can be firmly sustained by the matrix. The fraction of Al2O3 particles in composite may be adjusted between 23%～57%.
1998, 15(4): 59-63.
Abstract:
Based on the limitation of classical signal processing methods in case of nonstationality, the modules maximum evolution behavior of singular and random noise in multiscale space was analyzed using the WT. A simulation AE signal was processed. And an effective algorithm was presented to obtain the useful signal about the place information from the simulation signal. It shows the nice future of the application in the active damage detection of composite material.
Based on the limitation of classical signal processing methods in case of nonstationality, the modules maximum evolution behavior of singular and random noise in multiscale space was analyzed using the WT. A simulation AE signal was processed. And an effective algorithm was presented to obtain the useful signal about the place information from the simulation signal. It shows the nice future of the application in the active damage detection of composite material.
1998, 15(4): 64-68.
Abstract:
In this paper, the distributed parameter transfer function method was applied to analyze the correlation between vibration and stability of composite combined beams under axial compression. The state space equations for vibration and stability of composite laminated beams under axial compression have been derived for arbitrary boundary conditions. The relationship between the natural frequency and the axial compression load was obtained in which the effects of the shear deformation and the rotary inertia were taken into consideration. The influences of length to thickness ratio, material anisotropy and torsion's effect on natural frequencies and buckling loads were also investigated. The numerical results were compared with the experimental results and the corresponding results published in the references.
In this paper, the distributed parameter transfer function method was applied to analyze the correlation between vibration and stability of composite combined beams under axial compression. The state space equations for vibration and stability of composite laminated beams under axial compression have been derived for arbitrary boundary conditions. The relationship between the natural frequency and the axial compression load was obtained in which the effects of the shear deformation and the rotary inertia were taken into consideration. The influences of length to thickness ratio, material anisotropy and torsion's effect on natural frequencies and buckling loads were also investigated. The numerical results were compared with the experimental results and the corresponding results published in the references.
1998, 15(4): 69-73.
Abstract:
Tensile tests after low velocity impact were carried out on honeycomb core sandwich specimens. Some methods were used to study the cause of tensile failure: X ray, deply, and visual inspection. The relationship between residual tensile strength and impact energy was analyzed. Results showed that, in the course of tension, four failure modes existed meanwhile and interacted each other. Impact damage affected tensile ability of honeycomb core sandwich panels seriously.
Tensile tests after low velocity impact were carried out on honeycomb core sandwich specimens. Some methods were used to study the cause of tensile failure: X ray, deply, and visual inspection. The relationship between residual tensile strength and impact energy was analyzed. Results showed that, in the course of tension, four failure modes existed meanwhile and interacted each other. Impact damage affected tensile ability of honeycomb core sandwich panels seriously.
1998, 15(4): 74-80.
Abstract:
In this paper, dynamic behavior of orthotropic honeycomb sandwich plates is investigated layer by layer with high order theory of Reddy. Dynamic equations of honeycomb sandwich plates are derived. Free vibration of one dimensional orthotropic honeycomb sandwich plates is investigated deeply. Frequency equations and functions of vibration mode are given when two sides, opposite to each other, are simply supported. How frequency is influenced by thickness of core and ratios of thickness to span is analyzed simultaneously. The results are compared with those of low order theory. The result of comparison proves that high order theory is better than low order theory.
In this paper, dynamic behavior of orthotropic honeycomb sandwich plates is investigated layer by layer with high order theory of Reddy. Dynamic equations of honeycomb sandwich plates are derived. Free vibration of one dimensional orthotropic honeycomb sandwich plates is investigated deeply. Frequency equations and functions of vibration mode are given when two sides, opposite to each other, are simply supported. How frequency is influenced by thickness of core and ratios of thickness to span is analyzed simultaneously. The results are compared with those of low order theory. The result of comparison proves that high order theory is better than low order theory.
1998, 15(4): 81-88.
Abstract:
In this paper rolling tires——a typical rubber composite structure was analyzed by nonlinear FEM using several new techniques. The boundary value problem and FE modeling of rolling tires were presented. Also their solving scheme was developed. Taking spinning configuration as reference one, time can be eliminated out from inertial fields and governing equations. Rolling contact problem was handled by increment constraint method with tire contact friction force and vertical pressure between tire and roadway developed. The effect of operational condition on total and local displacement and load is studied. The computed results agree with data and experiments available, which shows the methods in this paper are reasonable.
In this paper rolling tires——a typical rubber composite structure was analyzed by nonlinear FEM using several new techniques. The boundary value problem and FE modeling of rolling tires were presented. Also their solving scheme was developed. Taking spinning configuration as reference one, time can be eliminated out from inertial fields and governing equations. Rolling contact problem was handled by increment constraint method with tire contact friction force and vertical pressure between tire and roadway developed. The effect of operational condition on total and local displacement and load is studied. The computed results agree with data and experiments available, which shows the methods in this paper are reasonable.
1998, 15(4): 89-96.
Abstract:
The law of tensile strength of short fiber/rubber composites(SFRCs) was studied for the first time among a wide range of fiber volume and length. Based on the Cox shear lag and characters of SFRC, a new mixture law was put forward and the longitudinal tensile strengths of SFRCs were theoretically predicted.The results show that the new model includes more comprehensive structure factors and predicted values can well suit experimental values. In addition, the mechanism of tensile fracture of SFRCs was investigated; it was thought that fracture of SFRCs was controlled by the interface between fibers and matrix and there existed a competitive course between the increase of interfacial shear stress and increase of tensile stress on the fibers, where the former restricted the latter.
The law of tensile strength of short fiber/rubber composites(SFRCs) was studied for the first time among a wide range of fiber volume and length. Based on the Cox shear lag and characters of SFRC, a new mixture law was put forward and the longitudinal tensile strengths of SFRCs were theoretically predicted.The results show that the new model includes more comprehensive structure factors and predicted values can well suit experimental values. In addition, the mechanism of tensile fracture of SFRCs was investigated; it was thought that fracture of SFRCs was controlled by the interface between fibers and matrix and there existed a competitive course between the increase of interfacial shear stress and increase of tensile stress on the fibers, where the former restricted the latter.
1998, 15(4): 97-101.
Abstract:
A fatigue testing system for polyester cord/rubber composites was established in this paper. Based on this system, the fatigue properties of unidirectional polyester cord/rubber composites under cyclic loading were assessed and the fatigue life prediction equation of rubber composites was given. The study also examined the effect of strain, frequency and temperature on the damage accumulation process of rubber composites. The results indicated that fatigue lifetime and damage accumulation of rubber composites were strongly influenced by cyclic frequency because of hysteretic loss of the materials. This paper offers a method available for evaluating the fatigue behavior of tires and predicting the fatigue lifetime of tires.
A fatigue testing system for polyester cord/rubber composites was established in this paper. Based on this system, the fatigue properties of unidirectional polyester cord/rubber composites under cyclic loading were assessed and the fatigue life prediction equation of rubber composites was given. The study also examined the effect of strain, frequency and temperature on the damage accumulation process of rubber composites. The results indicated that fatigue lifetime and damage accumulation of rubber composites were strongly influenced by cyclic frequency because of hysteretic loss of the materials. This paper offers a method available for evaluating the fatigue behavior of tires and predicting the fatigue lifetime of tires.
1998, 15(4): 102-106.
Abstract:
Based on modified classical laminated theory, the mechanical properties of three dimensionally braided composite materials were analyzed in this paper. Carrying out the integration and averaging of compliances yields, the effective elastic modulus of braided structural composites was predicted. Tsai Wu polynomial criterion was adopted and the strengths of 3 D braided composites were obtained. In addition, the mechanical experiments of braided structural composite materials were carried out. The effects of textile process parameters, such as braider angle, transverse angle, ratio of axial yarns number to braider yarns number and fiber volume fraction on mechanical properties were investigated. A comparison between theoretical and experimental results shows that the mechanical model can reasonably predict the stiffness and strength of 3 D braided composite materials.
Based on modified classical laminated theory, the mechanical properties of three dimensionally braided composite materials were analyzed in this paper. Carrying out the integration and averaging of compliances yields, the effective elastic modulus of braided structural composites was predicted. Tsai Wu polynomial criterion was adopted and the strengths of 3 D braided composites were obtained. In addition, the mechanical experiments of braided structural composite materials were carried out. The effects of textile process parameters, such as braider angle, transverse angle, ratio of axial yarns number to braider yarns number and fiber volume fraction on mechanical properties were investigated. A comparison between theoretical and experimental results shows that the mechanical model can reasonably predict the stiffness and strength of 3 D braided composite materials.
1998, 15(4): 107-112.
Abstract:
Dynamic mechanical characteristics of carbon fiber/epoxy braided structural reinforced composites are studied by means of the experimental modal analysis technique and the vibration modal parameters and the frequency response functions of braided composites beam and tube are analyzed. By comparison with dynamic properties of steel beam and tube, the results reveal that advanced braided structure composite has good dynamic mechanics behavior such as relatively high natural frequencies, damping ratios and the ratio of stiffness to weight as well as fairly good stabilization and the obvious effect of shock absorption on the impulsive pulse.
Dynamic mechanical characteristics of carbon fiber/epoxy braided structural reinforced composites are studied by means of the experimental modal analysis technique and the vibration modal parameters and the frequency response functions of braided composites beam and tube are analyzed. By comparison with dynamic properties of steel beam and tube, the results reveal that advanced braided structure composite has good dynamic mechanics behavior such as relatively high natural frequencies, damping ratios and the ratio of stiffness to weight as well as fairly good stabilization and the obvious effect of shock absorption on the impulsive pulse.
1998, 15(4): 113-118.
Abstract:
The FGM optimization design mainly depends on the design of gradient distribution function (GDF). By considering a power law function as GDF in the analysis, the FGM optimization was simplified to search for the optimum gradient power, i.e ., GP. The spalling analyses and optimization design of functional gradient film/substrate structure are presented in this paper. Energy release rates and stress intensity factors of the substrate crack parallel to the interface were obtained to determine the optimum GP. The relation between the thermal stress relaxation and antithermal or antioxidal properties has also been discussed.
The FGM optimization design mainly depends on the design of gradient distribution function (GDF). By considering a power law function as GDF in the analysis, the FGM optimization was simplified to search for the optimum gradient power, i.e ., GP. The spalling analyses and optimization design of functional gradient film/substrate structure are presented in this paper. Energy release rates and stress intensity factors of the substrate crack parallel to the interface were obtained to determine the optimum GP. The relation between the thermal stress relaxation and antithermal or antioxidal properties has also been discussed.
1998, 15(4): 119-127.
Abstract:
The problem considered here is the antiplane response of a nonhomogeneous composite material containing some cracks subjected to dynamic loadings. It is assumed that the composite material is orthotropic and all the material properties only depend on the co ordinate y (along the thickness direction). In the analysis, the elastic region is divided into a number of strips of infinite length. The material properties are taken to be constants for each strip. By utilizing the Laplace transform and Fourier transform technique, the general solutions for strips are derived. The complete solution of the entire elastic region is then obtained through introducing the mechanical boundary and strip interface conditions via the flexibility/stiffness matrix approach. Attention is focused on the time dependent full field solutions of stresses, stress intensity factor and strain energy release rate. As a numerical illustration, the dynamic stress intensity factor of a functionally graded material with two cracks under sudden applied forces on crack faces are presented for various material nonhomogeneity parameters.
The problem considered here is the antiplane response of a nonhomogeneous composite material containing some cracks subjected to dynamic loadings. It is assumed that the composite material is orthotropic and all the material properties only depend on the co ordinate y (along the thickness direction). In the analysis, the elastic region is divided into a number of strips of infinite length. The material properties are taken to be constants for each strip. By utilizing the Laplace transform and Fourier transform technique, the general solutions for strips are derived. The complete solution of the entire elastic region is then obtained through introducing the mechanical boundary and strip interface conditions via the flexibility/stiffness matrix approach. Attention is focused on the time dependent full field solutions of stresses, stress intensity factor and strain energy release rate. As a numerical illustration, the dynamic stress intensity factor of a functionally graded material with two cracks under sudden applied forces on crack faces are presented for various material nonhomogeneity parameters.
1998, 15(4): 128-133.
Abstract:
In this paper,the incremental formulation of Hamilton Semi Analytical Method and corresponding computational process for transient nonlinear thermo elastic problem are given. The numerical results on thermo stresses and deformation are obtained for the composite laminates during the cooling down stage of cure process. The results indicate that the nonlinear effect of the temperature dependent mechanical properties is important on residual thermo stress of composite laminates for the cure analysis.
In this paper,the incremental formulation of Hamilton Semi Analytical Method and corresponding computational process for transient nonlinear thermo elastic problem are given. The numerical results on thermo stresses and deformation are obtained for the composite laminates during the cooling down stage of cure process. The results indicate that the nonlinear effect of the temperature dependent mechanical properties is important on residual thermo stress of composite laminates for the cure analysis.
1998, 15(4): 134-138.
Abstract:
Fibers are randomly arranged in a continuous fiber reinforced composite, and this affects its mechanical characteristics. This fact was investigated via numerical simulation; and some modules were calculated considering the fiber arrangement. Conclusions are drawn from the coarse calculation, and the tentative work shows the importance of considering the effect of fiber arrangement in micro mechanics of composite.
Fibers are randomly arranged in a continuous fiber reinforced composite, and this affects its mechanical characteristics. This fact was investigated via numerical simulation; and some modules were calculated considering the fiber arrangement. Conclusions are drawn from the coarse calculation, and the tentative work shows the importance of considering the effect of fiber arrangement in micro mechanics of composite.
1998, 15(4): 139-144.
Abstract:
Weak formulation of mixed state equation including boundary conditions is presented in a cylindrical coordinate system by introducing Hellinger-Reissner variational principle. Analytical solutions were obtained for laminated open cylindrical shells. The present study extends and unifies solution of laminated open shells.
Weak formulation of mixed state equation including boundary conditions is presented in a cylindrical coordinate system by introducing Hellinger-Reissner variational principle. Analytical solutions were obtained for laminated open cylindrical shells. The present study extends and unifies solution of laminated open shells.
ANALYSIS ON STABILITY CHARACTERISTICS OF QUASI STATIC GROWTH OF A BRIDGED DELAMINATION IN COMPOSITES
1998, 15(4): 145-150.
Abstract:
In this paper, some new results of axisymmetric post buckling and stability characteristics of growth of a thin film delamination bridged by through thickness fiber tows in a 3D composites are presented. An iterative procedure combined with Taylor's series expansion is used to generate a family of nondimensionalized post buckling solutions of the thin film delamination based on von Karman's nonlinear plate theory. The energy release rate G and the fracture toughness Γ ( ψ , Δ c 1) associated with uniform propagation of a circular delamination are obtained. An important conclusion that the bridge force not only increases the initial growth strain ε * 0 but also obstructs the catastrophic growth of the delamination is drawn from numerical results. In addition, quantitatively the following results are derived: (1) the effect of bridge force on the initial growth of the delamination during post buckling phase, and (2) the regions of stable and unstable growth of the bridged delamination, and (3) the assessment of the range and the dynamic effect of unstable growth for the delamination propagating from unstable to stable.
In this paper, some new results of axisymmetric post buckling and stability characteristics of growth of a thin film delamination bridged by through thickness fiber tows in a 3D composites are presented. An iterative procedure combined with Taylor's series expansion is used to generate a family of nondimensionalized post buckling solutions of the thin film delamination based on von Karman's nonlinear plate theory. The energy release rate G and the fracture toughness Γ ( ψ , Δ c 1) associated with uniform propagation of a circular delamination are obtained. An important conclusion that the bridge force not only increases the initial growth strain ε * 0 but also obstructs the catastrophic growth of the delamination is drawn from numerical results. In addition, quantitatively the following results are derived: (1) the effect of bridge force on the initial growth of the delamination during post buckling phase, and (2) the regions of stable and unstable growth of the bridged delamination, and (3) the assessment of the range and the dynamic effect of unstable growth for the delamination propagating from unstable to stable.
