4. Extreme theorems

The fact that the material obeys the principle of maximum work has remarkable mathematical consequences in the form of two theorems established around 1952, which enable the equations of plastic flow to be solved in a more or less approximate manner.

We also assume that the RPP body has a uniform flow stress, but the demonstration remains valid if this flow stress varies from point to point in a fixed way.

It should also be noted that their extension to take account of the boundary conditions imposed by the tools and the consequences of friction are generally not clearly justified.

Finally, more...