Fatigue "safe-life" criterion for metal elements under multiaxial static and dynamic random loads

Abstract

Random stress with Cartesian components of known statistical moments of their mean values and power spectral densities of stochastic stress processes is considered. To account for the mean stress effect the generalised Soderberg criterion for ductile materials is employed. An equivalent stress with periodic (in the mean-square sense) components is defined by means of the equivalence conditions based on the average strain distortion energy. 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 fatigue limits which: have simple physical interpretation, can be determined by uniaxial tests, are directly related to the applied loads, and can reflect material anisotropy.