PREDICTION OF FATIGUE DAMAGE AND FATIGUE LIFE UNDER RANDOM LOADING

The objective of the present paper is to find the fatigue damage and fatigue life of a structural component when subjected to variable-amplitude stress loading modeled as a wide-band or narrow-band Gaussian random process. In addition to the well-known Palmgren-Miner's linear damage rule, a nonlinear plastic work interaction damage rude is used as a basis for the accumulation of fatigue damage which gives us a more conservative fatigue life estimation as compared to the Palmgren-Miner rule. Numerical examples are performed and comparison is made for the fatigue damage and fatigue life evaluated under various random loading conditions and based on different damage rules. Several conclusions are drawn at the end of the paper which give us simpler rules to be used in the analysis and design of fatigue structures when subjected to random loading conditions.