PSI - Issue 2_A

Itsuki Kawata et al. / Procedia Structural Integrity 2 (2016) 2463–2470

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Author name / Structural Integrity Procedia 00 (2016) 000–000

(a) Type A estimated with parameters from Type B

(b) Type B estimated with parameters from Type A Fig.6. Results of CTOD tests and simulated critical CTOD with parameters obtained from other specimen.

(a) Type A estimated with parameters from Type B (b) Type B estimated with parameters from Type A Fig.7. Comparison of location of fracture initiation sites between experiment and simulation with parameters obtained from other specimen.

6. Conclusions The authors proposed a new method for obtaining parameters of a probabilistic fracture model. In the present method, locations of fracture initiation site are used in a likelihood function in addition to fracture toughness parameters. Moreover, a new probabilistic fracture initiation model was proposed, in which non-linear effect of plastic strain on micro crack nucleation probability was considered. The authors applied the present method and the present model to experimental results using the same material and two different specimen configuration in order to confirm the advantage of the present method. As a result, the authors concluded that probabilistic parameters obtained from the present method shows less dependency on plastic constraint than those obtained from the conventional method and the present model can estimate fracture probability and distribution of fracture initiation site more accurately. References Beremin, F.M., 1983. A local criterion for cleavage fracture of a nuclear pressure vessel steel. Metallurgical and Materials Transactions A 14A, 2277–2287. Bordet, S.R, Karstensen, A.D., Knowles, D.M., Wiesner, C.S., 2005a. A new statistical local criterion for cleavage fracture in steel. Part I: model presentation. Engineering Fracture Mechanics 72, 435–452. Bordet, S.R, Karstensen, A.D., Knowles, D.M., Wiesner, C.S., 2005b. A new statistical local criterion for cleavage fracture in steel. Part II: application to an offshore structural steel. Engineering Fracture Mechanics 72, 453–474. Hiraide, T., Shibanuma K., Aihara, S., 2015. Development of Numerical Model to Predict Cleavage Fracture Toughness of Ferrite-Pearlite Steels. Tetsu-to-Hagané 101, 384-393. (in Japanese) Shibanuma, K., Aihara. S., Ohtsuka, S., 2013. Observation and Quantification of Crack Nucleation in Ferrite-Cementite Steel. Tetsu-to-Hagané 99, 582-591. (in Japanese). WES 1108: Standard test method for Crack-Tip Opening Displacement (CTOD) fracture toughness measurement, The Japan Welding Engineering Society. 1995. Yoshizu, S., Nakai. H., Shibanuma. K., Yoshinari, H., Aihara, S., 2014. Probabilistic Fracture Mechanics Analysis on the Scatter of Critical CTOD. Procedia Materials Science 3, 1447-1452.