To assess the reliability and the scope of applicability of the defining relations of mechanics of damaged media (MDM) [1,2], plastic deformation and damage accumulation processes in a number of structural steels under low-cycle loading have been numerically investigated, and the obtained numerical results have been compared with the data from fullscale experiments. It is shown that the introduced MDM model qualitatively and quantitatively describes the main effects of plastic deformation and damage accumulation processes in structural alloys under block-type non-stationary non-symmetric low-cycle loading.