Structural integrity material fracture toughness

Fracture toughness is a measure of a material s resistance to failure in the presence of a flaw of known or presumed size and a known or presumed stress. The relationship between the flaw (or crack) and the stress is designated the stress intensity, K. For structural integrity evaluations of RPVs, the plane-strain fracture toughness is designated Ki and is determined... 

Fracture mechanics is a systems approach to estimate the relationship between the stresses, the flaw geometry, and the material properties as it relates to the structural integrity of the component under consideration. The primary objectives are to prevent failures, promote effective design, and make efficient use of materials. The modern approach seeks a parameter that is a measure of the material s toughness that is independent of the geometry, and can be used with stress analysis to predict fracture loads and critical crack sizes. Using this toughness value from a test specimen in the laboratory, the flaw sizes at which fracture will occur for the structural component used in service can be predicted. The reverse scenario is also... 

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