Abstract
The macroscopic elastic-plastic constitutive relation of inhomogeneous material is affected not only by the characteristics of respective constituents, but also by the microscopic distribution of stress and strain in heterogeneous regions. In order to describe the deformation behaviour of inhomogeneous material, several parameters are defined. A plane model of inhomogeneous material with inclusions is used for numerical simulation, and the changes in the parameters during elastic-plastic deformation are calculated and compared. Uniaxial loading under the plane-strain condition is assumed. It is concluded that the initial aspect ratio has a marked influence on the deformation behaviour. One of the parameters, called the constraint ratio, remains nearly constant with increase in the applied strain or the degree of inhomogeneity. This characteristic seems to be important for estimating the deformation behaviour of inhomogeneous material. The constitutive relation of inhomogeneous material may also be estimated from the value of the constraint ratio.
