Evaluation and uncertainty estimates of Charpy-impact data

Conference · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5322197

Stallman, F W

Shifts in transition temperature and upper-shelf energy from Charpy tests are used to determine the extent of radiation embrittlement in steels. In order to determine these parameters reliably and to obtain uncertainty estimates, curve fitting procedures need to be used. The hyperbolic tangent or similar models have been proposed to fit the temperature-impact-energy curve. These models are not based on the actual fracture mechanics and are indeed poorly suited in many applications. The results may be falsified by forcing an inflexible curve through too many data points. The nonlinearity of the fit poses additional problems. In this paper, a simple linear fit is proposed. By eliminating data which are irrelevant for the determination of a given parameter, better reliability and accuracy can be achieved. Additional input parameters like fluence and irradiation temperature can be included. This is important if there is a large variation of fluence and temperature in different test specimens. The method has been tested with Charpy specimens from the NRC-HSST experiments.

• Research Organization: Oak Ridge National Lab., TN (USA); Tennessee Univ., Knoxville (USA). Dept. of Mathematics
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5322197
• Report Number(s): CONF-820321-6; ON: DE82009621
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360106* -- Metals & Alloys-- Radiation Effects
ALLOYS
CHARPY TEST
DESTRUCTIVE TESTING
EMBRITTLEMENT
IMPACT TESTS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS TESTING
MATHEMATICAL MODELS
MECHANICAL TESTS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
STEELS
TESTING