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 < σ ₀ correspond to those where the material remains rigid, and the case σ = σ ₀ defines the stress allowing plastic deformation.