Applicability of new CTOD calculation formula to various a(0)/W conditions and B x B configuration

作者：Kawabata Tomoya^*; Tagawa Tetsuya; Kayamori Yoichi; Ohata Mitsuru; Yamashita Yoichi; Kinefuchi Masao; Yoshinari Hitoshi; Aihara Shuji; Minami Fumiyoshi; Mimura Hiroshi; Hagihara Yukito

来源：Engineering Fracture Mechanics, 2017, 179: 375-390.

DOI：10.1016/j.engfracmech.2017.03.027

• Toughness testing
• Test standards
• Crack tip opening displacement
• Plastic hinge model
• Rotational factor
• Strain hardening

In the previous report, the authors proposed a new CTOD calculation formula which shows good correspondence with actual CTOD in large thickness materials by introduction of a correction parameter for varied blunting shapes at the crack tip by a strain hardening exponent. However, this formula is limited to the standard range of the crack depth to width ratio, a(0)/W from 0.45 to 0.55, and hence did not satisfy strong demand for evaluation of a wider a(0)/W range. Actually, 15015653 can cover a wider a(0)/W range from 0.01 to 0.70 in order to respond to this demand, considering the description in the Annex, which specifies a J-integral based CTOD calculation formula. In the context of this situation, the authors' recent report revealed that the plastic hinge model can be applied to a(0)/W conditions other than the range from 0.45 to 0.55 based on detailed observation of plastic deformation for wider a(0)/W conditions. Coordination of the rotational center is steady regardless of the load level and strain hardening exponent. In this study, first, based on a B x 2B configuration, expansion of the applicable a(0)/W range for the proposed CTOD calculation formula is investigated with some modification of the proposed formula. Second, application to the B x B type specimen is investigated. Finally, validation of the FEM analysis for B x B type specimens by the silicone rubber replica method is presented.

• 出版日期2017-6-15