Thin sections fracture

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Fracture mechanics-based procedures for assessing the integrity of structures containing defects rely on the availability of fracture toughness measurements. Each of these measurements is made using a test specimen containing a crack, with the specimen size and geometry generally being chosen, in line with accepted fracture toughness testing standards, to generate high-magnitude tensile hydrostatic stresses local to the crack front during fracture. However, this approach can result in an excessively conservative underestimate of the failure load of a cracked component of interest being made in cases where the tensile hydrostatic stresses local to the crack front in the structure are lower in magnitude that those in the laboratory specimen used to determine the fracture toughness. The aim of the present project is to develop a method for determining an accurate estimate of the failure load of a given thin-walled steel component containing either a through-wall crack or a semi-elliptical/extended surface crack. This will entail considering the way in which the stress state varies along the crack front for a variety of component thicknesses. A range of load levels will be considered between the extremes of linear-elastic and fully-plastic behaviour.