3. Elastoplastic behavior

In contrast to the uniaxial case, the relationship between stress and strain is no longer sufficient to describe elastoplastic behavior in an analysis of continuous two- and three-dimensional media.

Multiaxial loading tests demonstrate the existence of an initial elasticity domain as a function of the Cauchy stress tensor. As long as loading remains within this domain, deformations remain reversible.

Figure 10 illustrates the criteria obtained from tests on metals, subjected to a loading path consisting of axial stress followed by shear.