EN
Periodic stress with Cartesian components given in the form of Fourier series is conside-red. To account for the mean stress effect the generalised Soderberg criterion for ductilematerials is employed. An equivalent stress with synchronous components is defined bymeans of the equivalence conditions based on the average strain energy of distortion. Thefatigue "safe-life" design criterion is formulated which covers the conditions of both staticstrength and fatigue safety and includes material constants that have simple physical in-terpretation, can be determined by uniaxial tests, are related directly to the applied loadsand can reflect material anisotropy