Fig. 3
True and apparent configurations of a solid-fluid mixed material according to the biphasic theory. In the true configuration, the space dΩt can be divided in the solid space \(\mathrm {d}\Omega _{T}^{s}\) and the fluid space \(\mathrm {d}\Omega _{T}^{f}\). In the biphasic theory, these discontinuous spaces are assumed to be macroscopically continuous and to occupy the whole mixture space dΩt. Therefore, two constituents occupy the same physical space at the same time