Coupling of Fracture Mechanics and Transition Temperature Approaches to Fracture-Safe Design

摘要

The effect of mechanical constraint on the transition temperature features for steels of thick section is examined in the framework of linear elastic fracture mechanics and tests and the Dynamic Tear (DT) test. Steels of fracture toughness and yield strength levels representative of the A533-B type exhibit a transition to high fracture toughness in thick sections. The distinguishing feature of thick sections is a size effect involving a shift of the transition temperature midpoint on the order of 60F. The DT test defines a limiting transition temperature region, which can be divided into three parts: a low temperature regime in which plane strain fracture mechanics is applicable, a higher temperature regime which is beyond the limits of fracture mechanics definition and is relatable to crack arrest conditions, and a final regime involving large plastic deformation in association with the fracture. (Author)