Weight function solution of stress intensity factors for delayed hydride cracking of zirconium alloys

Abstract

Considering the formation of the dual-phase microstructure of hydrides and the zirconium matrix by delayed hydride cracking (DHC), the complete stress field at the crack tip was obtained based on Eshelby’s inclusion theory and the extended finite element method (XFEM). The length of the fracture process zone was calculated by combining the Dugdale−Barenblatt model with the weight function, and the stress intensity factor of a finite-width sheet with an edge crack DHC model was obtained by the weight function. It was found that the stress intensity factor increased rapidly with the increasing crack length before the crack passed through the hydride completely. When the hydride crack length reached3.67μm, DHC initiated. It was also found that the discrepancy between the theoretical and experimental critical stress intensity factors implies that the crack-tip region was covered with a two-phase material instead of the hydride only.