PSI - Issue 5

Yoichi Kayamori et al. / Procedia Structural Integrity 5 (2017) 279–285 Yoichi Kayamori et al. / Structural Integrity Procedia 00 (2017) 000 – 000

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7

4. Discussion

As shown in Fig.4, analytically obtained  was influenced by Y/T , and estimated  by Eqs. from (9a) to (10) was closely located to the analytical  . The new CTOD design curve proposed in this study therefore gives a good CTOD estimation for different Y/T steels. However, as shown in Figs.1 and 2, the behavior of m was complex, and m was influenced by Y/T ,  /  y and  /  y c . Furthermore, only one kind of welded joint with a crack, namely, a corner boxing fillet welded joint with a semi-elliptical surface crack, was employed for evaluating the applicability of the proposed design curve equations to CTOD estimation in this study. Further investigation for other welded joints and crack sizes should be carried out in the future.

5. Concluding remarks

In this study, a new CTOD design curve was formulated for evaluating the effect of Y/T on  , and the following equations were proposed as the design curve:

         

2

   

   







  

  

for

1



m





y

y





c



y

   

   

   

    

2



2 1





  

  

for

1



m





y

y

Y T m 3.4 1.6 /    These equations give a good CTOD estimation for different Y/T steels.

Acknowledgements

This study was partly conducted in the CTOD Testing Committee of the Japan Welding Engineering Society. Useful discussions in the committee are greatly appreciated.

References

ASTM International, 2002, Standard Test Method for Crack-Tip Opening Displacement (CTOD) Fracture Toughness Measurement, ASTM E1290. Begley, J. A., Landes, J. D., Wilson, W. K., 1974, An Estimation Model for the Application of the J-integral, Fracture Analysis, ASTM STP 560, 155-169. British Standards Institution, 1991, Fracture Mechanics Toughness Tests. Method for Determination of K IC , Critical CTOD and Critical J Values of Metallic Materials, BS7448-1. International Organization for Standardization, 2008, Metallic Materials - Unified Method of Test for the Determination of Quasistatic Fracture Toughness, ISO 12135. Kayamori, Y., Inoue, T., Hiramatsu, H., Michiba, K., Aihara, S., Hagihara, Y., 2008, Improvement of CTOD Calculation in Japanese Flaw Assessment Methods of WES2805, 2008 ASME Pressure Vessels and Piping Division Conference, Chicago, Illinois, USA, PVP2008-61256. Nagai, K., Yajima, H., Kajimoto, K., Hino, T., Minami, N., 1980, On the Characteristics of Brittle Fracture Initiation in a Structurally Stress Concentrated Region (2nd Report), Journal of the Japan Society of Naval Architects and Ocean Engineers, 148, 169-176. Nagai, K., Yajima, H., Kajimoto, K., Hino, T., Ozawa, A., Saeki, T., 1982, On the Characteristics of Brittle Fracture Initiat ion in a Structurally Stress Concentrated Region (3rd Report), Journal of the Japan Society of Naval Architects and Ocean Engineers, 151,223-230. Nagai, K., Yajima, H., Kajimoto, K., Kawano, H., Nawata, T., 1984, On the Characteristics of Brittle Fracture Initiation in a Structurally Stress Concentrated Region (4th Report), Journal of the Japan Society of Naval Architects and Ocean Engineers, 155,360-367. Tagawa, T., Kawabata, T., Sakimoto, T., Kayamori, Y., Ohata, M., Yamashita, Y., Tamura, E., Yoshinari, H., Aihara, S., Minami, F., Mimura, H., Hagihara, Y., 2014, A new CTOD Calculation Formula Considering Strain-Hardening Properties, Procedia Materials Science, 3, 772-777. The Japan Welding Engineering Society, 2016, Standard Test Method for Crack-Tip Opening Displacement (CTOD) Fracture Toughness Measurement, WES 1108. The Japan Welding Engineering Society, 2011, Method of Assessment for Flaws in Fusion Welded Joints with Respect to Brittle Fracture and Fatigue Crack Growth, WES 2805.