A Principle of Maximum Plastic Resistance

Heretofore a complete determination of stresses in a plastic body has been dependent upon a successful analysis of deformation in plastic flow, the method of computation being essentially based on Nadai’s stress-strain relations. The principle of maximum plastic resistance, as introduced in this paper, establishes a new method of computation of stresses only, without any explicit reference to deformation. Formally, the principle is progressive, since it supplies equations sufficient for solution; intrinsically and physically, the principle treats the plastic body as a reacting medium automatically producing maximum values of resultant reaction. Combined plastic tension, torsion, and inner pressure (in a boiler) are chosen as cases in which to apply the principle. The results are condensed in the relative diagram accompanying the paper.