Elastodynamic fracture analysis of large crack-arrest experiments

Recent elastodynamic fracture analysis results are summarized from Heavy-Section Steel Technology (HSST) studies in two major areas that relate to assessing nuclear reactor pressure vessel integrity under pressurized-thermal-shock conditions. These areas are crack run-arrest behavior in wide plates under nonisothermal conditions and fracture behavior of a thick-wall vessel under combined thermal and pressure loadings. The WP-1 series of HSST wide-plate crack-arrest tests are being performed at the National Bureau of Standards (NBS) using specimens from HSST Plate 13A of A533 grade B class 1 steel. The six tests in the WP-1 series are aimed at providing crack-arrest data at temperatures up to and above that corresponding to the onset of the Charpy upper-shelf, as well as providing information on dynamic fracture processes for use in evaluating improved fracture analysis methods. In this paper, the computed results are compared with data for crack-line strain-time response, crack-propagation speed, arrest location and post-arrest tearing. The paper includes a summary of the arrest toughness calculations compiled in the four tests at temperatures that range from transition to upper-shelf values for the wide-plate material. These same elastodynamic fracture analysis techniques have been applied to the analysis of the first pressurized-thermal-shock experiment performed at ORNL. The experiment addressed warm-prestressing phenomena, crack propagation from brittle to ductile regions, and crack stabilization in ductile regions. Test and analysis results are summarized in the paper