Determining equations for compressible plastic porous solids

Conclusions

The scalar properties of a compressible porous solid can be characterized by a pair of equations expressing the dependence of hydrostatic pressure p and tangential stress intensity t on the ratio between the rates of volume change e and shape change γ, porosity, and parameters characterizing the state of the material of the powder and the porous solid. The p and τ functions must satisfy Eq. (14), with p being a monotonically increasing limited function of S=e/γ and t increasing at S ≤0, attaining a maximum at S = 0, and decreasing at S ⩾0; at ¦S¦ → ∞ τ → 0. During the plastic deformation of compressible materials, hydrostatic pressure can affect shear strains, while tangential stresses can lead to volume changes. Together with this form there exists a form of determining equations expressed by the loading surface equation (16) and the relationship (18). In the case of a rigorously convex surface these two forms are equivalent.