Plasticity in forming

As seen in § 4.1 of the [42] dossier, rigid-plastic behavior is a schematization of the actual behavior of metal alloys. It serves as the basis for the construction of all more realistic plastic behavior models. It is therefore particularly instructive to present it first.

The aim of this theory is to describe the behavior of RPP material in a more general state of stress and strain than that observed in single-load tests (tension, torsion, bending), and to specify the relationships between the quantities measured in these various tests. To achieve this, it is necessary to make various assumptions and initially neglect the finer phenomena encountered in real materials.

The fundamental notions of plasticity have a very simple but fundamental framework, namely the rigid-plastic body or RPP.

In this issue, we look at :

• plasticity criterion ;

• plastic flow law ;

• description of friction ;

• a statement of theorems for analyzing shaping operations;

• at the end, a significant illustration through the example of rolling with traction of thin sheets.