validation and case studies

(01 May 2006) FITNET MK7Test Programme on 85mm Thick A533B Specimens for Warm Pre-stressFigure 13.12 – Wide plate test specimens for WPS tests on 85 mm plate.Uniaxial wide plate tests were carried out on four 85mm thick specimens, containing semi-elliptical notchessharpened by fatigue (Figure 13.12 and Table 13.4). Three (ID 17-19) comprised A533B material that hadbeen quenched and tempered, whilst one (ID 20) was in the as-rolled condition, intended to be representativeof an irradiation-embrittled material. Specimens ID 17 and 18 were pre-stressed at 70 o C and then cooled to-44 o C and loaded to failure. Around 20mm of ductile tearing occurred during the warm pre-stress period.Specimen ID 20 was warm pre-stressed and held at load while cooled to –20 o C, where fracture occurred.Specimen ID 19 was not pre-stressed. All tests were loaded using a dual hydraulic loading ram to apply bothmembrane and bending stress.Table 13.4 – Specimen identification and specifications.ID, this workID, originalworkCracktypeNominalthickness,[mm]MaterialconditionPre-stresstemperature[ºC]Testtemperature,[ºC]17 22771/M01-0118 22771/M01-0219 23200/M01-0120 22771/M01-01SCT 85 Q&T 70 -44SCT 85 Q&T 70 -44SCT 85 Q&T - -44SCT 85 as-rolled 70 -20Fracture toughness data are available for this material in the form of single point values of K J and CTOD,along with CTOD and J R-curves. Single point K J data were used in the BS 7910 Level 2 analysis shown inFigure 13.13. Note that for one of the plates (ID 19), yield level residual stress was assumed to account for thefact that a weld associated with the bending capsule loading flange was located only 60mm from the notch.The analysis of ID 19 gives the result closest to the FAD line, and if a negligible residual stress is assumed theresult is not conservative. On the FAD, the higher value of L r cut-off relates to specimens ID 17-19 (Q&Tsteel), while the lower value is that for ID 20 (as-rolled material).© FITNET 2006 – All rights reserved 13-13