Prediction of Temperature Dependence and Scatter in Fracture Toughness of Pressure Vessel Steel using Nonlocal Damage Models

Abstract

Abstract The pressure vessel and piping components may be subjected to operation in the ductile-to-brittle transition regime of the material due to increase in the transition temperature. This increase can be due to irradiation embrittlement, vario s other material aging and degradation mechanisms taking place in a nuclear reactor environment. From fracture mechanics point of view, fracture toughness of the material must be adequate to prevent the failure. However, there is considerable scatter observed in the fracture toughness data and the analyst must account for this in the safety analysis. Master curve approach according to ASTM E1921 standard is popularly employed for this purpose. However, it requires the data for transition temperature T0, which is dependent upon the specimen geometry and loading configurations employed in the laboratory tests. Its transferability to safety analysis of components is questionable. Towards this objective, the authors have recently developed a nonlocal formulation for the Rousselier's damage model and combined this with the Beremin's model to predict the variation of fracture toughness and its scatter in the DBTT regime for the standard compact tension specimens. In this work, application of this new procedure to different types of geometry and loading conditions has been explored.