Plasticity criterion
Plasticity in forming

We aim to generalize the notion of plastic flow threshold observed in the one-dimensional case of tensile testing.

In this case, the set of possible uniaxial stresses σ verifies the scalar relationship (figure 8 c in the [42] file):$\sigma -{\sigma }_0⩽0$

Stresses σ < σ₀ correspond to those where the material remains rigid, and the case σ = σ₀ defines the stress allowing plastic deformation.

We therefore need to define all the stress states likely to cause plastic deformation. For this purpose, we introduce a scalar function f of...