Evaluation of Fatigue Crack Front Shape for a Specimen with Finite Thickness

Two-dimensional elastic or elasto-plastic models dominate the current fatigue crack growth assessment and life prediction procedures for plate components with through-the-thickness cracks. However, as demonstrated in many theoretical and experimental papers, the stress field near the crack tip is always three-dimensional and the fatigue crack front is not straight. In this paper, we develop a simplified approach for the evaluation of the front shapes of through-the-thickness fatigue cracks. We validate this approach against experimental results available from published papers.