A general model for stress‐life fatigue prediction

From several factors that influence the fatigue behaviour of a particular material, the stress ratio or mean stress and the stress concentration factor are of great importance for the structural calculation. Since most components and structural members contain notches that could be sites of fatigue crack initiation, fatigue data from specimens with different forms of notches have to be collected. The collection of such data at various stress ratios or mean stresses is not economic and time‐consuming. Based on the Walker equivalent stress model, a general fatigue life model is presented and tested with 2024‐T3 fatigue data, available in the literature. The Walker model considered only the effect of stress ratio or mean stress on the fatigue behaviour. On the other hand, in the proposed model, the combined effect of mean stress and stress concentration factor on fatigue behaviour is demonstrated. The statistical analysis indicates that the presented model is very efficient to interpolate the fatigue life successfully, thereby reducing both time and cost.