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Journal Articles

Effect of local plastic component on crack opening displacement and on J-integral of a circumferential penetrated crack

Machida, Hideo*; Arakawa, Manabu*; Wakai, Takashi

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05

This paper describes the effect of local plastic component on J-integral and crack opening displacement (COD) evaluation of a circumferential penetrated crack, applicable to the leak before break (LBB) assessment for sodium cooled fast reactor (SFR) components. J-integral COD evaluation methods are generally formulated as a summation of elastic and plastic components, and so far many evaluation formulae based on these two components have been proposed. However, strictly, the plastic component consists of local plastic and fully plastic components. Many of the conventional evaluation methods often consider only the fully plastic component as the plastic component. The reason for this is that the effect of the local plastic component is much smaller than that of the fully plastic component excluding materials with extremely small work hardening. In contrast, for materials with high yield stress and small work hardening, such as modified 9Cr-1Mo steel which is one of the candidate materials for SFR piping, the effect of the local plastic component on J-integral and COD cannot be ignored. Therefore, the authors propose formulae taking the effect of local plastic component on J-integral and COD into account, based on finite element analysis (FEA) results, so that it is easy to apply to crack evaluation. The formulae will be employed in the guidelines on LBB assessment for SFR components published from Japan Society of Mechanical Engineers (JSME).

Journal Articles

Fracture mechanics of a postulated crack in ITER vacuum vessel

Kurihara, Ryoichi; Ueda, Shuzo; Tada, Eisuke

Fusion Technology, 30(3), p.1465 - 1469, 1996/12

no abstracts in English

JAEA Reports

Crack extension analysis under pressurized thermal shock loading by ADINA

Isozaki, Toshikuni; Shibata, Katsuyuki; *; *

JAERI-Research 96-039, 133 Pages, 1996/07

JAERI-Research-96-039.pdf:3.85MB

no abstracts in English

JAEA Reports

Revisions of fracture mechanics parameters analysis code CANIS-J(2D)

Furuhashi, Ichiro*; Wakai, Takashi

PNC TN9410 95-080, 84 Pages, 1995/02

PNC-TN9410-95-080.pdf:2.82MB

Revisions have been done on CANIS-J(2D) that calculates fracture mechanics parameters of 2-dimensional structures containing cracks or notches. (a)Evaluation of △K between arbitrary two steps on the basis of △. (b)Evaluation of △J and △J $_{hat}$ between arbitrary two steps on the basis of △, △ε and △u. (c)Evaluation of each terms of J (△J)-integral and J $_{hat}$ (△J $_{hat}$ )-integral. (d)Execution of following three mode calculations in one job run. Mode- 0 calculation of K, J and J $_{hat}$ at any step. Mode- 1 calculation of △K, △J and △J $_{hat}$ between arbitrary two steps. Mode- 2 calculation of J and J $_{hat}$ between any continuous steps. To verify the validity of the revised code, we performed fracture mechanics analyses and crack growth simulations of thermal fatigue crack growth tests of circumferentially slitted cylinders subjected to cyclic thermal transients. And we got following results. (1)At thermal-elastic and at thermal-elasto-plastic conditions, J (△J) - integral is not path-independent and can not be properly evaluated. The reason is that J - integral is defined at elastic condition. (2)At thermal-elastic and at thermal-elasto-plastic conditions, J $_{hat}$ (△J $_{hat}$ ) -integral is good enough path-independent and can be properly evaluated. The reason is that J $_{hat}$ -integral is defined at more generalized stress conditions. (3)△J $_{hat}$ hat, thermal-elastic △K △ (or △ε) at near the crack tip, and net-section bending stress range S $_{n}$ at crack ligament, these take approximate maximum values between the common two steps. (4)Crack growth simulations based on △J $_{hat}$ agree well with the behaviors observed at tests. (5)These results assist that, on the fracture mechanics evaluations of flawed structures subjected to complicated thermal-elasto-plastic load cycles, J $_{hat}$ (△J $_{hat}$ ) -integral will be a possible fracture mechanics parameter which corresponds to ...

JAEA Reports

Fracture toughness tests of 9 Cr type steels at elevated temperature; 2 nd. Report

*; ; ; *; *

PNC TN9410 91-132, 85 Pages, 1991/06

PNC-TN9410-91-132.pdf:1.47MB

A series of high temperature fracture toughness tests of 9Cr type steels was put in practice on a three-years scheme in 1988. In this experimental study, Mod.9Cr-1Mo steel, 9Cr-2Mo steel and 9Cr-1Mo-Nb-V steel are tested, and these fructure toughness are investigated on the basis of J integral. In a first year, high temperature fracture toughness test method was established using R-curve method and unloading compliance method, and J $_{a}$ values of Mod. 9Cr-1Mo steel were measured at RT, 400 $^{circ}$ C, 500 $^{circ}$ C, 550 $^{circ}$ C and 600 $^{circ}$ C. In a second year, fracture toughness tests of 9Cr-2Mo steel, 9Cr-1Mo-V-Nb steel and these aged materials were performed, and several factors which affected fracture toughness values of 9Cr type steels were clarified. In this report, the test results in a second year are summarized. In a last year, fracture toughness tests of weldment and thick plate of 9Cr type steel are going to be carried out. Furthermore, an effect of crack direction on J $_{a}$ value will be studied.

JAEA Reports

Fracture toughness test of 9Cr type steel at elevated temperature (No.1)

*; *; Kano, Shigeki; *; *; *; *

PNC TN9410 89-096, 105 Pages, 1989/05

PNC-TN9410-89-096.pdf:2.31MB

A series of high temperature fracture toughness tests of 9Cr type steel was put in practice on a three-year scheme in 1988, In this experimental study, Mod.9Cr-1Mo steel, 9Cr-2Mo steel and TEMPALOY SW-9(9Cr-1Mo-Nb-V) steel are tested, and fracture toughness (J $_{Q}$ ) of base metal (As-received, SR-treated, Aged) and weldment (weld metal, HAZ) of these three types of steel are investigated. In a first year, fracture toughness tests of base metal (As-received, SR-treated) of Mod.9Cr-1Mo steel were carried out at RT, 400 $^{circ}$ C, 500 $^{circ}$ C, 550 $^{circ}$ C and 600 $^{circ}$ C, respectively. In this report, the test results in the first year are shown. Fracture toughness tests were performed using R-curve method and unloading compliance method according to ASTM E813. The fracture toughness value was the lowest at 400 $^{circ}$ C. Even at 400 $^{circ}$ C, however, Mod.9Cr-1Mo steel showed enough high fracture toughness (J $_{c}$ 350kJ/m $^{2}$ ), In the fracture toughness test, tearing modurous T $_{mat}$ was also measured.