The endochronic equations proposed by Valanis (1980) were extended to a finite deformation range. Jaumanns rate, Fus rate and Wus rate were incorporated into the endochronic equations to analyze simple shear finite de...The endochronic equations proposed by Valanis (1980) were extended to a finite deformation range. Jaumanns rate, Fus rate and Wus rate were incorporated into the endochronic equations to analyze simple shear finite deformation. Incremental equations and numerical solutions are deduced for three endochronic objective models. The results show that an oscillatory shear stress response to a monotonically increasing shear strain occurs when the Jaumanns rate objective model is employed for endochronic materials. The oscillatory response is dependent on the adopted objective rate. Compared with the Jaumanns rate, the Fus rate and the Wus rate satisfy the restrictions to elastic-plastic constitutive relations and are in agreement with the experimental results.展开更多
In order to investigate the effect of microvoids on the mechanical behavior of casting magnesium alloy,a spherical void-cell model of the material was presented.The velocity and strain fields of the model were obtaine...In order to investigate the effect of microvoids on the mechanical behavior of casting magnesium alloy,a spherical void-cell model of the material was presented.The velocity and strain fields of the model were obtained from the assumption that the material matrix is homogeneous and incompressible.The hardening and softening functions,which respectively reflect the deformation-hardening and void-softening behaviors of the material,were presented and introduced to an endochronic constitutive equation for describing the mechanical behavior of the material including microvoids.The corresponding numerical algorithm and finite element procedure were developed and applied to the analyses of the elastoplastic response and the porosity of casting magnesium alloy ZL102.The computed results show satisfactory agreement with experimental data.展开更多
文摘The endochronic equations proposed by Valanis (1980) were extended to a finite deformation range. Jaumanns rate, Fus rate and Wus rate were incorporated into the endochronic equations to analyze simple shear finite deformation. Incremental equations and numerical solutions are deduced for three endochronic objective models. The results show that an oscillatory shear stress response to a monotonically increasing shear strain occurs when the Jaumanns rate objective model is employed for endochronic materials. The oscillatory response is dependent on the adopted objective rate. Compared with the Jaumanns rate, the Fus rate and the Wus rate satisfy the restrictions to elastic-plastic constitutive relations and are in agreement with the experimental results.
基金Project(10872221)supported by the National Natural Science Foundation of China
文摘In order to investigate the effect of microvoids on the mechanical behavior of casting magnesium alloy,a spherical void-cell model of the material was presented.The velocity and strain fields of the model were obtained from the assumption that the material matrix is homogeneous and incompressible.The hardening and softening functions,which respectively reflect the deformation-hardening and void-softening behaviors of the material,were presented and introduced to an endochronic constitutive equation for describing the mechanical behavior of the material including microvoids.The corresponding numerical algorithm and finite element procedure were developed and applied to the analyses of the elastoplastic response and the porosity of casting magnesium alloy ZL102.The computed results show satisfactory agreement with experimental data.
