The stress intensity factor is a measure of the stress field around a crack tip, and is defined as:
where da/dN is the crack growth rate, C and m are material constants, and ΔK is the stress intensity factor range. principles of fracture mechanics rj sanford pdf pdf work
The investigation revealed that the pipeline had been fabricated using a welding process, and that the weld had not been properly heat-treated. As a result, the weld region had a higher yield strength and a lower toughness than the base metal. The stress intensity factor is a measure of