Approximate expressions of maximum value of stress intensity factor of nozzle corner cracks

Based on the flat plate-nozzle model loaded by uniform uniaxial tension, through some suitable reduction and approximation, the maximum value of stress intensity factor (K) along a crack front can be expressed by the weight function method for the flat plate-nozzle that is loaded by the uniform uniaxial tension and cylinder-nozzle loaded by internal pressure separately. This approach can be valuable for the prediction of fatigue life and failure analysis of pressure vessels. The results so calculated are compared with those reported in the literature and from experiments here reported; and they show good agreement, the discrepancies being less than 15%. This shows that the approximate expressions are effective and can be used in practice.