The basic equations and relations of the theory of elastic-plastic deformation processes in plane problems are presented for arbitrary paths, with both the generalized Baushinger's effect under complex loading and secondary plastic deformation taken into consideration. In solution of the basic equations using universal approximations of functionalities of processes, the fourth-order accuracy Runge-Kutta numerical method is utilized. In order to validate the reliability of calculated data, results of our simulations are compared with the corresponding experimental data obtained using the SN-EVM testing system.