J-Integral Determinations and Analyses for Small Test Specimens and Their Usefulness for Estimating Fracture Toughness

General estimation procedures for the J-integral determination are reviewed for the three-point bend and the compact tension specimens. Tests were made using 10 CD 9-10 steel. Experimental results are presented and are inpartial agreement with analytical results. The errors due to simplified analysis and experimental procedure are explored. Toughness, as analyzed by the resistance curve technique, is shown to be size dependent for bending and not for tension. Disagreement between the two loading modes, if not fortuitous and due to the steel, suggests that simple strain and stress analyses are not sufficient and that the loading procedure and the T-effect must be taken into account.