Simple flow rules for modeling the behavior of inhomogeneous viscoplastic materials

The use of 'Iso-W' approach for generating a simple flow rule for inhomogeneous viscoplastic materials was proposed. The 'Iso-W' approach can be extended to mixtures of viscoplastic materials and generalized to generate model, each of then depending on a single parameter. The 'Iso-W' assumption in the case of linear constituents and the self-consistent model for both linear and nonlinear materials, provided that the flow stress contrast of the two phases is not too large, and the volume fraction of the soft phase is not too small. The results show that the volumic work increase associated with a strain increment was identical in the various constituents of the materials.