Volume 35, Issue 3 (May 2007)
Crack Initiation Determination for Three-Point-Bend Specimens
The paper deals with the determination of crack initiation for three-point-bend specimens during fracture toughness testing of materials in the upper transition and upper shelf region. In the presented study various published methods such as the Double Clip Gage Method, the Strain Near to Crack Tip Measurement method, the Double Displacement Method, the Compliance Changing Rate Method, and the Stretch Width Zone measurement were applied together with the methods using the crack extension versus crack mouth opening displacement and force versus displacement for the crack initiation determination. Blunting line based evaluation were also performed and all results were compared. The investigation was carried out on five different steels.