Ductile fracture initiation near axial crack fronts in pressure tubes of hydrided irradiated Zr-2.5Nb materials with split circumferential hydrides

摘要

Highlights?Determine near-tip stresses and J-integral along axial crack front in pressure tube.?Determine fracture patterns of radial and circumferential hydrides near crack front.?Determine fracture initiation location along axial crack front in pressure tube.?Visualize plastic strain concentration between split circumferential hydrides.?Quantify reduced fracture toughness for hydrided irradiated Zr-2.5Nb pressure tube.AbstractDuctile fracture initiation with consideration of strain concentration and stress triaxiality near axial crack fronts in pressure tube (PT) specimens of hydrided irradiated Zr-2.5Nb materials with split circumferential hydrides is examined by three-dimensional finite element analyses with submodeling. For a PT specimen with split circumferential hydrides, strain concentration occurs in the middle of the ligaments ahead of the crack front. The computational results suggest that only 60–70% of the internal pressure for fracture initiation of an unhydrided irradiated PT specimen is needed to fracture a hydrided irradiated PT specimen with many split circumferential hydrides along the crack front.]]>