Incorporation of obstacle hardening into local approach to cleavage fracture to predict temperature effects in the ductile to brittle transition regime

Research output: Contribution to journalArticlepeer-review

55 Downloads (Pure)

Abstract

Ductile-to-brittle-transition refers to observable change of fracture mode with decreasing temperature—from slow ductile crack growth to rapid cleavage. It is exhibited by body-centred cubic metals and presents a challenge for integrity assessment of structural components made of such metals. Local approaches to cleavage fracture based on Weibull stress as cleavage crack-driving force have been shown to predict fracture toughness at very low temperatures. However, they are ineffective in the transition regime without recalibration of Weibull stress parameters, which requires further testing and thus diminishes their predictive capability. We propose new Weibull stress formulation with thinning function based on obstacle hardening model, which modifies the number of cleavage-initiating features with temperature. Our model is implemented as post-processor of finite element analysis results. It is applied to analyses of standard C(T) specimens of typical reactor pressure vessel steel, for which deformation and fracture toughness properties in the transition regime are available. It is shown that the new Weibull stress is independent of temperature, and of Weibull shape parameter, within experimental error. It predicts accurately the fracture toughness at any temperature in the transition regime without relying upon empirical fits for the first time.
Original languageEnglish
Article number1224
Pages (from-to)1-12
Number of pages12
JournalMaterials
Volume14
Issue number5
DOIs
Publication statusPublished - 5 Mar 2021

Keywords

  • cleavage fracture
  • finite element analysis
  • local approach
  • Weibull stress

Research Beacons, Institutes and Platforms

  • Advanced materials

Fingerprint

Dive into the research topics of 'Incorporation of obstacle hardening into local approach to cleavage fracture to predict temperature effects in the ductile to brittle transition regime'. Together they form a unique fingerprint.

Cite this