In order to analyze the stress and strain fields in the fibers and the matrix in composite materials,a fiber-scale unit cell model is established and the corresponding periodical boundary conditions are introduced.Ass...In order to analyze the stress and strain fields in the fibers and the matrix in composite materials,a fiber-scale unit cell model is established and the corresponding periodical boundary conditions are introduced.Assuming matrix cracking as the failure mode of composite materials,an energy-based fatigue damage parameter and a multiaxial fatigue life prediction method are established.This method only needs the material properties of the fibers and the matrix to be known.After the relationship between the fatigue damage parameter and the fatigue life under any arbitrary test condition is established,the multiaxial fatigue life under any other load condition can be predicted.The proposed method has been verified using two different kinds of load forms.One is unidirectional laminates subjected to cyclic off-axis loading,and the other is filament wound composites subjected to cyclic tension-torsion loading.The fatigue lives predicted using the proposed model are in good agreements with the experimental results for both kinds of load forms.展开更多
A study of composite laminates under tension–torsion biaxial loading is presented.The focus is placed on fatigue lives of composite laminates under different tension–torsion biaxial fatigue loading paths.A macro-mes...A study of composite laminates under tension–torsion biaxial loading is presented.The focus is placed on fatigue lives of composite laminates under different tension–torsion biaxial fatigue loading paths.A macro-meso model used to predict multiaxial fatigue life of composite laminates is also presented in this paper.Firstly,a macro-scale 3 D RVE corresponding to composite laminates is established to determine strain components in the material principal direction of each layer for each biaxial stress ratio.Secondly,a meso-scale 3 D RVE corresponding to each layer with fibers distributed randomly is established,with progressive damage prediction method,biaxial strength of composite laminates can be predicted,and the final failure layer can be confirmed.Thirdly,select any one of fatigue loading path at which the final failure of composite laminates is fiber failure(matrix failure)to establish the reference curve for fiber(matrix).Finally,with reference curve,fatigue life of composite laminates under any biaxial loading path can be predicted.And numerical results show good agreements with experimental data.展开更多
基金the supports from the Jiangsu Province Key Laboratory of Aerospace Power System of China(No.NJ20140019)the National Natural Science Foundation of China(No.51205190)
文摘In order to analyze the stress and strain fields in the fibers and the matrix in composite materials,a fiber-scale unit cell model is established and the corresponding periodical boundary conditions are introduced.Assuming matrix cracking as the failure mode of composite materials,an energy-based fatigue damage parameter and a multiaxial fatigue life prediction method are established.This method only needs the material properties of the fibers and the matrix to be known.After the relationship between the fatigue damage parameter and the fatigue life under any arbitrary test condition is established,the multiaxial fatigue life under any other load condition can be predicted.The proposed method has been verified using two different kinds of load forms.One is unidirectional laminates subjected to cyclic off-axis loading,and the other is filament wound composites subjected to cyclic tension-torsion loading.The fatigue lives predicted using the proposed model are in good agreements with the experimental results for both kinds of load forms.
文摘A study of composite laminates under tension–torsion biaxial loading is presented.The focus is placed on fatigue lives of composite laminates under different tension–torsion biaxial fatigue loading paths.A macro-meso model used to predict multiaxial fatigue life of composite laminates is also presented in this paper.Firstly,a macro-scale 3 D RVE corresponding to composite laminates is established to determine strain components in the material principal direction of each layer for each biaxial stress ratio.Secondly,a meso-scale 3 D RVE corresponding to each layer with fibers distributed randomly is established,with progressive damage prediction method,biaxial strength of composite laminates can be predicted,and the final failure layer can be confirmed.Thirdly,select any one of fatigue loading path at which the final failure of composite laminates is fiber failure(matrix failure)to establish the reference curve for fiber(matrix).Finally,with reference curve,fatigue life of composite laminates under any biaxial loading path can be predicted.And numerical results show good agreements with experimental data.
