On real and ideal materials

Various plasticity theories are discussed as models for the behavior of real materials. The simple rigid/perfectly plastic model is shown to be a reasonable first approximation. Once the theory for this model has been developed, it is easily modified to account for strain hardening and elastic effects. It is shown in various examples that, for loads less than the rigid/perfectly plastic limit load, strain hardening has a negligible effect, whereas for greater loads elastic strains can reasonably be neglected.