Plastic #eta#-factor for three-point bend specimens: Analysis of instrumented Charpy impact test results for AISI 308 weld and AISI 316 stainless steels

摘要

In this paper, instrumented impact test resultsobtained using V-notch and precracked Charpy specimens ofAISI 308 weld and AISI 316 stainless steels are analysed fordetermining the plastic #eta#-factor for 'bee-point bendspecimens used in J-integral evaluation. Tested 316 stainlesssteel specimens were in various thermal aging/cold-workconditions whereas 308 weld specimens were in the as-weldedcondition. The results at analysed using the various proceduresproposed in the literature and compared with experimental andfinite element results reported in the literature. Based on ouranalysis, two polynomial expressions of #alpha#/W for#eta#_(pl) are presented: one gives a sort of upper-bound in the#alpha#/W range 0.05-1.0 while the other gives conservativevalues (i.e., use of this results in J-R curves and J sufficientlyconservative for engineering purposes). Both provide smoothvariation of #eta#_(pl) over the entire #alpha#/W range unlikesome of the expressions given in the literature which show adiscontinuous change at an intermediate #alpha#/W.