A scheme of boundary element method for moving contact of two-dimensional elastic bodies using conforming discretization is presented. Both the displacement and the traction boundary conditions are satisfied on the co...A scheme of boundary element method for moving contact of two-dimensional elastic bodies using conforming discretization is presented. Both the displacement and the traction boundary conditions are satisfied on the contacting region in the sense of discretization. An algorithm to deal with the moving of the contact boundary on a larger possible contact region is presented. The algorithm is generalized to rolling contact problem as well. Some numerical examples of moving and rolling contact of 2D elastic bodies with or without friction, including the bodies with a hole-type defect, are given to show the effectiveness and the accuracy of the presented schemes.展开更多
Based on the experimental results of local temperature field formed in the evolution period of defects, the defect field is defined by this internal temperature field. The evolutionary processes of statistically corre...Based on the experimental results of local temperature field formed in the evolution period of defects, the defect field is defined by this internal temperature field. The evolutionary processes of statistically correlative meso-scopic defects are analysed with the growth rate and nucleation rate of the meso-defect, and it is deemed that the dynamic failure process of the viscoelastic material with defects can be quantitatively described by the normal method of the procedure of heat wave transmission. The defect field is regarded as a complex system of the union of the real sets and null sets, its main characteristics depending on the stratum hypothesis about the activities of the subsystems of the highest stratum described by ordered parameters. The fluctuation of ordered parameters is demonstrated by means of the projection operator method. The constitutive equation with ordered parameters for the meso-defect evolutionary state of viscoelastic material with defects is deduced from the nonlinear rheological dynamic approach, and its solution is obtained.展开更多
In this paper we consider the cable as a bundle consisting of x sub-bundles, with m parallel tension members per sub-bundle, and the tension members themselves are polymeric yarns impregnated with a resin matrix. The ...In this paper we consider the cable as a bundle consisting of x sub-bundles, with m parallel tension members per sub-bundle, and the tension members themselves are polymeric yarns impregnated with a resin matrix. The nonfailad members at any instant must share an applied system load according to some rule, since there is a clearly expressed dependence of the fracture on the duration on the duration and character of the loading. So then, the fracture of cable is a process of nonlinear dynamic evolution, which accommodates to the non-equilibrium thermodynamics of irreversible processes by itself. Let us assume that the polymeric yarns art as viscoelastic solid, under certain probabilistic assumptions, according to the principles of rheology of bodies with defects, the relationship between the single member loading and failure and the bundle loading are investigated. It can be shown that the bundle failure time is asymptotically normally distributed as the number of members grows large. After a study of the second order effects of random slack, it is known that the asymptotic mean and variance are functions of the parameters of loading and single member theological behavior. Hence the loss in the asymptotic bundle strength mean brought about by random member and sub-bundle slack, L(s), and the loss in the asymptotic bundle strength variance caused by random member slack, Delta(s), are determined. And finally, if is known that the asymptotic time of failure can make up a considerable part of the fracture of cable, and the fracture of cable is a time-dependent process of rheological fracture.展开更多
基金The project supported by the National Natural Science Foundation of China (19772025)
文摘A scheme of boundary element method for moving contact of two-dimensional elastic bodies using conforming discretization is presented. Both the displacement and the traction boundary conditions are satisfied on the contacting region in the sense of discretization. An algorithm to deal with the moving of the contact boundary on a larger possible contact region is presented. The algorithm is generalized to rolling contact problem as well. Some numerical examples of moving and rolling contact of 2D elastic bodies with or without friction, including the bodies with a hole-type defect, are given to show the effectiveness and the accuracy of the presented schemes.
基金The project supported by National Natural Science Foundation of China(NNSF 19632002).
文摘Based on the experimental results of local temperature field formed in the evolution period of defects, the defect field is defined by this internal temperature field. The evolutionary processes of statistically correlative meso-scopic defects are analysed with the growth rate and nucleation rate of the meso-defect, and it is deemed that the dynamic failure process of the viscoelastic material with defects can be quantitatively described by the normal method of the procedure of heat wave transmission. The defect field is regarded as a complex system of the union of the real sets and null sets, its main characteristics depending on the stratum hypothesis about the activities of the subsystems of the highest stratum described by ordered parameters. The fluctuation of ordered parameters is demonstrated by means of the projection operator method. The constitutive equation with ordered parameters for the meso-defect evolutionary state of viscoelastic material with defects is deduced from the nonlinear rheological dynamic approach, and its solution is obtained.
文摘In this paper we consider the cable as a bundle consisting of x sub-bundles, with m parallel tension members per sub-bundle, and the tension members themselves are polymeric yarns impregnated with a resin matrix. The nonfailad members at any instant must share an applied system load according to some rule, since there is a clearly expressed dependence of the fracture on the duration on the duration and character of the loading. So then, the fracture of cable is a process of nonlinear dynamic evolution, which accommodates to the non-equilibrium thermodynamics of irreversible processes by itself. Let us assume that the polymeric yarns art as viscoelastic solid, under certain probabilistic assumptions, according to the principles of rheology of bodies with defects, the relationship between the single member loading and failure and the bundle loading are investigated. It can be shown that the bundle failure time is asymptotically normally distributed as the number of members grows large. After a study of the second order effects of random slack, it is known that the asymptotic mean and variance are functions of the parameters of loading and single member theological behavior. Hence the loss in the asymptotic bundle strength mean brought about by random member and sub-bundle slack, L(s), and the loss in the asymptotic bundle strength variance caused by random member slack, Delta(s), are determined. And finally, if is known that the asymptotic time of failure can make up a considerable part of the fracture of cable, and the fracture of cable is a time-dependent process of rheological fracture.
