EN
Random stress with Cartesian components of known statistical moments of their meanvalues and power spectral densities of stochastic stress processes is considered. To acco-unt for the mean stress effect the generalised Soderberg criterion for ductile materials isemployed. An equivalent stress with periodic (in the mean-square sense) components isdefined by means of the equivalence conditions based on the average strain distortionenergy. Also, is formulated the fatigue "safe-life" design criterion which covers the condi-tions of both static strength and fatigue safety and includes yield strengths and fatiguelimits which : have simple physical interpretation, can be determined by uniaxial tests, are directly relatedto the applied loads, and can reflect material anisotropy