Stress Intensity Factors during Brittle Crack Propagation and at Crack Arrest

Abstract

Quantitative evaluation of stress intensity factors during brittle crack propagation and at crack arrest was made by applying the X-ray diffraction technique to the fracture surface of compact specimens of a pressure vessel steel SA533B Cl. 1. The stress intensity factor determined using the half value breadth of the X-ray diffraction intensity curve from the fracture surface decreased gradually as the crack propagated, and then it oscillated before arrest. The stress intensity factor at crack arrest was not necessarily the minimum value obtained during the crack propagation. The stress intensity factor at crack arrest was in good agreement with the crack arrest toughness K_Ia determined by the static analysis, while it was smaller than K_ID by the dynamic one.