A statistical model for the analysis and prediction of the effect of neutron irradiation on Charpy impact energy curves

Interpretation of Charpy impact energy characteristics by microstructural evolution of dynamically compressed specimens in three tempered martensitic steels

“…The toughness of steels is often predicted by a simplified semi-empirical formula obtained from the correlation of fracture speed with crack propagation speed [9,10]. In the case of the high-strength steels such as tempered martensitic steels, however, the correlation of Charpy USE with fundamental fracture process or crack speed is less obvious [11][12][13].…”

Uncertainty and risk associated with the Charpy impact energy of multi-run welds

“…The magnitude of the change associated with the temperature selected to mark the location of the transition region is an indication of the degree of fracture toughness degradation (weld metal embrittlement). Often (in the nuclear industry in particular) only sparse data are available for establishing whether there has been a fracture toughness degradation due to irradiation (Windle et al, 1996).…”

“…In the present study, the temperature corresponding to 40 J Charpy impact energy (T 40 J temperature) was selected to mark the location of the ductile-to-brittle transition region (Windle et al, 1996).…”

An overview of the principles of modeling charpy impact energy data using statistical analyses

“…For these, specimens of the pressure vessel steels were installed in canisters, at defined locations within an individual reactor, to monitor principally the tensile and Charpy impact energy properties in different reactors. In view of the recently proposed statistical procedures developed for analyzing Charpy impact energy data, [5,6] this article considers the various issues and reasons relevant to the interpretation of mechanical property data. The resulting data obtained from the separate reactor schemes have been analyzed to derive relationships which provide trends for changes of mechanical properties as a function of neutron irradiation dose and temperature.…”

“…Surveillance specimens have been withdrawn from these reactors after different periods of service to provide measurements of these mechanical properties for a range of neutron irradiation doses and temperatures. [5,6] In Section V, we provide a demonstration of the statistical analysis using artificially generated Charpy impact energy data, and in Section VI, we comment upon the use of statistical analyses in the context of the requirements for structural integrity assessments. [2] The trend curves for the yield and ultimate tensile strengths describe the effect of neutron irradiation dose and temperature by comparing, for example, the yield strength of the material irradiated to different neutron dose levels with the unirradiated control condition.…”