Surface cracks in fatigued structural components: a review

Surface cracks are a common occurrence in structural components due to the frequently highest values of the stress at the outer boundary of the body and to the presence of defects. Such flaws can heavily reduce the service life of structural components leading to their premature failure, especially under repeated loading. During last decades, many research works based on theoretical, numerical and experimental techniques have been performed, mainly devoted to the determination of the stress-intensity factors for recurrent surface crack shapes, different loading types and boundary conditions. Further, fatigue behaviour of surface cracks has been examined through numerical analyses or by simplifying the expected crack growth process. In the present paper, a literature survey is carried out by discussing the main topics related to the safety assessment of structural components with surface cracks under static or fatigue loading.