Fracture Assessment of Wide Plate Component Subjected to Biaxial Loading

Abstract

This study investigated the effect of biaxial loading on the fracture performance of a center through cracked panel and a center surface cracked panel of a structural steel of 25mm thick. The experiment revealed that the critical CTOD of the biaxially loaded specimen was smaller than that of the uniaxially loaded specimen, due to the constraint effect of the biaxial loading. This constraint effect was remarkable in the case of the through thickness notched specimen. The stress distributions near the cracks and crack tip deformation behaviors were simulated by FE-analyses, in order to discuss brittle fracture initiation conditions of the cracked wide plate specimens. All fracture initiation points were located in the large CTOD part of the crack front, as well as in the widely extended high opening stress region. However, the initiation points did not always correspond to the highest opening stress point along the crack front. These results indicated that the existence of a extensive high stress region accompanied by a large CTOD, is significant in the brittle fracture initiation condition. These results also suggested that fracture assessment based on the Weibull stress criterion is reasonable, because the Weibull stress takes the volume effect of the high stress area into account.