Abstract <p>This version of the theory of elasto-plastic processes is based on the equations of the theory of plastic flow under combined hardening, which has been sufficiently verified under complex loading. The plasticity functionals of this version of the theory of elasto-plastic processes are determined using simple experiments involving uniaxial tension and tension after preliminary compression. Verification of this version of the theory of elasto-plastic processes is carried out under complex loading and complex unloading along a deformation path shaped like a right triangle.</p>