Fatigue crack growth from semi-elliptical surface defects

Existing guidance contained in both the draft British Standard 7910 (which is to replace the existing document PD6493) and the ASME Boiler and Pressure Vessel code, Section XI, for the assessment of defects tends to be either over conservative or sometimes non-conservative. To be able to assess the structural integrity of an engineering component or structure with confidence, a greater understanding of such defects and how they behave in service is required. The current work examines the behaviour of cracks growing from semi-elliptical defects, dealing with various factors which affect crack growth rates and crack shape development and thus total fatigue life.