0
Materials and Fabrication

Verification of the Estimation Methods of Strain Range in Notched Specimens Made of Mod.9Cr-1Mo Steel

[+] Author and Article Information
Masanori Ando, Nobuchika Kawasaki

Japan Atomic Energy Agency,
4002 Narita, Oarai,
Ibaraki 311-1393, Japan

Yuichi Hirose

Mitsubishi heavy industry, Ltd.,
5-717-1 Fukahori, Nagasaki,
Nagasaki 851-0392, Japan

Shingo Date

Mitsubishi heavy industry, Ltd.,
2-1-1 Shinhama, Arai, Takasago,
Hyogo 676-8686, Japan

Sota Watanabe

Mitsubishi heavy industry, Ltd.,
1-1-1 Wadamisaki, Hyogo, Kobe,
Hyogo 652-8585, Japan

Yasuhiro Enuma

Mitsubishi FBR systems,
2-34-17, Jingumae, Shibuya,
Tokyo 150-0001, Japan

Contributed by the Pressure Vessel and Piping Division of ASME for publication in the JOURNALOF PRESSURE VESSEL TECHNOLOGY. Manuscript received March 28, 2011; final manuscript received March 22, 2012; published online October 18, 2012. Assoc. Editor: Osamu Watanabe.

J. Pressure Vessel Technol 134(6), 061403 (Oct 18, 2012) (12 pages) doi:10.1115/1.4006902 History: Received March 28, 2011; Revised March 22, 2012

Several methods of estimating strain range at a structural discontinuity have been developed in order to assess component reliability. In a component design at elevated temperature, estimation of strain range is required to evaluate the fatigue and creep-fatigue damage. Therefore, estimation of strain range is one of the most important issues when evaluating the integrity of a component during its lifetimes. To verify the methods of estimating strain range for discontinuous structures, low cycle fatigue tests were carried out with notched specimens. All the specimens were made of Mod.9Cr-1Mo steel, because it is a candidate material for a primary and secondary heat transport system components of Japan Sodium-cooled Fast Reactor (JSFR). Displacement control fatigue tests and thermal fatigue tests were performed by ordinary uniaxial push–pull test machine and equipment generating the thermal gradient in the notched plate by induction heating. Several notch radii were employed to vary the stress concentration level in both kinds of tests. Crack initiation and propagation process during the tests were observed by a digital microscope and the replica method to define the failure cycles. Elastic and inelastic finite element analyses were also performed to estimate strain range for predicting fatigue life. Then, these predictions were compared with the test results. Several methods such as stress redistribution locus (SRL) method, simple elastic follow-up (SEF) method, Neuber's law, and the procedures employed by elevated temperature design codes were applied. Through these comparisons, the applicability and conservativeness of these strain range estimation methods, which is the basis of the fatigue and creep-fatigue life prediction, are discussed.

Copyright © 2012 by ASME
Your Session has timed out. Please sign back in to continue.

References

Sagayama, Y., Okada, K. and Nagata, T., 2009, “Progress on Reactor System Technology in the FaCT Project Toward the Commercialization of Fast Reactor Cycle System,” Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR2009), IAEA-CN-176-01-02.
Aoto, K., Kotake, S., Uto, N., Ito, T., Toda, M., 2009, “JSFR Design Study and R&D Progress in the FaCT Project,” Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR2009), IAEA-CN-176-01-07.
Sakai, T., Kotake, S., Aoto, K., Ito, T., Kamishima, Y. and Oshima, J., 2010, “Conceptual Design Study Toward the Demonstration Reactor of JSFR,” Proceedings of ICAPP '10, Paper No. 10285.
International code, 2007 ASME Boiler & Pressure Vessel code, 2007, Rules for Construction of Nuclear Facility Components, Section III, Division 1, Subsection NH, Class 1 components in elevated temperature service, The American Society of Mechanical Engineers, United States of America.
RCC-MR Code, 2002, Design and Constriction Rules for Mechanical Components of FBR Nuclear Islands, AFCEN, France.
Assessment procedure for the high temperature response of structures, 2003, Assessment procedure, R5, Issue 3, British Energy Generation Limited, United Kingdom.
Neuber, H., 1961, “Theory of Stress Concentration for Shear Strained Prismatical Bodies With Arbitrary Non-Linear Stress-Strain Low,” Trans. ASME, J. Appl. Mech., Volume 28, pp.544–550. [CrossRef]
JSME S NC2-2009, 2009, Code for Nuclear Power Generation Facilities,-Rules on Design and Construction for Nuclear Power Plants—Section II Fast Reactor Codes, Japan Society of Mechanical Engineers (In Japanese), Japan.
Kasahara, N., 2001, “Strain Concentration at Structural Discontinuities and Its Prediction Based on Characteristics of Compliance Change in Structure,” JSME Int. J. Ser. A, 44(3), pp.354–361. [CrossRef]
Kasahara, N., 2001, “Strain Concentration Mechanism During Stress Relaxation Process and Its Prediction,” The 7th International Conference on Creep and Fatigue at Elevated Temperatures (CREEP7), SA-12-3(006), pp.625–629.
Shimakawa, T., Nakamura, K. and Kobayashi, K., 2004, “Sophisticated Creep-Fatigue Life Estimation Scheme for Pressure Vessel Components Based on Stress Redistribution Locus Concept,” Proceedings of ASME PVP 2004, Paper No. PVP2004-2258.
Kasahara, N., Furuhashi, I., 2006, “Control Mechanisms of Stress Redistribution Locus in Structures,” Proceedings of ASME PVP 2006 ICPVT-11, Paper No. PVP2006-94038.
Bubphachot, B., Watanabe, O., Kawasaki, N. and Kasahara, N., 2011, “Crack Initiation Process for Semi-Circular Notched Plate in Fatigue Test at Elevated Temperature,” Trans. ASME, J. Pressure Vessel Technol., 133(3), 031403. [CrossRef]
Watanabe, O., Bubphachot, B., Kawasaki, N. and Kasahara, N., 2008, “Crack Initiation Process for Semi-Circular Notched Plate in Creep-Fatigue Test at Elevated Temperature,” Proceedings of ASME PVP 2008, Paper No. PVP2008-61409.
Isobe, N., Kawasaki, N., Ando, M. and Sukekawa, M., 2011, “Experimental Investigation of Strain Concentration Evaluation Based on the Stress Redistribution Locus Method,” J. Nucl. Sci. Technol., 48(4), pp.567–574. [CrossRef]
Stowell, E. Z., 1950, “Stress and Strain Concentration at a Circular Hole in an Infinite Plate,” National Advisory Committee for Aeronautics Report Technical Note 2073.
Hardrath, H. F., and Ohman, L., 1953, “A Study of Elastic and Plastic Stress Concentration Factors Due to Notched and Fillets in Flat Plate,” National Advisory Committee for Aeronautics Report No. 1117, pp.213–222.
Nakamura, H., Tsunenari, T. and Koe, S., 1978, “A Study on Fatigue Strength of Notched Specimen,” J. Soc. Mater. Sci. Jpn., 27(299), pp.773–779(in Japanese). [CrossRef]
Sethuraman, R., and Viswanadha Gupta, S., 2004, “Evaluation of Notch Root Elasto-Plastic Stress–Strain State for General Loadings Using an Elastic Solution,” Int. J. Pressure Vessels Piping, 81(4), pp.313–325. [CrossRef]
Ye, D., Matsuoka, S., Suzuki, N. and Maeda, Y., 2004, “Further Investigation of Neuber's Rule and the Equivalent Strain Energy Density (ESED) Method,” Int. J. Fatigue, 26(5), pp.447–455. [CrossRef]
Kawasaki, N., Takakura, K., Ohtani, T., Hayashih, M. and Yamada, Y., 1990, “Recent Design Improvements of Elevated Temperature Structural Design Guide for DFBR in Japan,” SMiRT15, Div. F, F04/4, pp.IV 161–168.
Kurome, K., Date, S., Sukekawa, M., Takakura, K., Kawasaki, N. and Tanaka, Y., 1999, “Material Strength Code of 316FR Stainless Steel and Modified 9Cr-1Mo Steel,” Proceedings of ASME PVP 1999, PVP-Vol. 391, P47-54.
The Power Reactor and Nuclear Fuel Development Corporation, 1988, “A Study on the Rationalization of Elevated Temperature Structural Design Standard—Standards for Strength of Material for Fast Breeder Reactor(1),” PNC Report No. PNC9410-88-105.
Watanabe, D., Chuman, Y., Otani, T., Shibamoto, H., Inoue, K. and Kasahara, N., 2006, “Measurement of Thermal Ratcheting Strain on the Structures by the Laser Speckle Method,” Proceedings of ASME PVP 2006, Paper No. PVP2006-ICPVT-11-93600.
Jimbo, M., Asano, M., Hirayama, H., Kishi, S. and Kawasaki, N., 1999, “Elevated Temperature Strength Evaluation Rules for BOX Structure in DFBR,” SMiRT15, DivF, F02/1, pp.49–55.
Kasahara, N., Nagata, N., Iwata, K. and Negishi, H., 1995, “Advanced Creep-Fatigue Evaluation Rule for Fast Breeder Reactor Components: Generalization of Elastic Follow-Up Model,” Nucl. Eng. Des., 155, pp.499–518. [CrossRef]
Nagata, T. and Imazu, A., 1985, “Advancement in Elevated Temperature Structural Design Guide for FBR,” Proceedings of Post Conference Seminar of 10th SMiRT on Construction Codes and Engineering Mechanics, 2A, pp.1–35.
Takakura, K., Ueta, M., Dozaki, K., Wada, H., Hirayama, H., Hayashi, M., Ozaki, H. and Ooka, Y., 1994, “Elevated Temperature Structural Design Guide for DFBR in Japan,” SMiRT13, Div.E, E05-1, pp.389–400.
Hirayama, H., Hayashi, M., Ueta, M., Ozaki, H., Wada, H., Ooka, Y. and Takakura, K., 1995, “Creep-Fatigue Evaluation Rules in Design Guide for DFBR in Japan,” ASME PVP-Vol. 313-2, pp.439–448.
Asayama, T., Tsukimori, K. and Morishita, M., 2001, “Innovative Technologies in the Structural Design of FBRs,” SMiRT16, Papers#1173, pp.1–9.
Maruyama, T., 1979, “Study on Low-Cycle Fatigue Strength Reduction Factor,” J. Soc. Mater. Sci. Jpn., 29(320), pp.452–457(in Japanese). [CrossRef]
Shingai, K., 2002, “Experimental Fatigue Life Rule in Low Cycle Fatigue Region Based on Cyclic Strain Behavior of Specimen with Notches,” Trans. Jpn. Soc. Mech. Eng., Ser. A, 68(670), pp.956–961(in Japanese). [CrossRef]
Coffin, L. F.,1973, “Fatigue at High Temperature,” Fatigue at Elevated Temperatures, ASTM, West Conshohocken, PA, pp.5–34, ASTM STP 520.
Asayama, T. and Jetter, R., 2008, “An Overview of Creep-Fatigue Damage Evaluation Methods and an Alternative Approach,” Proceedings of ASME PVP 2008, Paper No. PVP2008-61820.
Onizawa, T., Nagae, Y., Wakai, T. and Asayama, T., 2009, “Development of a Material Strength Code for Japanese Demonstration Fast Breeder Reactor,” Proceedings of ASME PVP 2009, Paper No. PVP2009-77984.

Figures

Grahic Jump Location
Fig. 1

Configuration of notched bar specimens for mechanical fatigue tests

Grahic Jump Location
Fig. 2

Configuration of the notched plate specimen for thermal fatigue tests and overview of the thermal gradient measurement tests

Grahic Jump Location
Fig. 3

Variation of the thermal history in the thermal gradient measurement tests

Grahic Jump Location
Fig. 4

Examples of 2D and 3D models and boundary conditions for FEA: (a) The sector model of a notched bar specimen (ρ = 11.2 mm), (b) the sector model of a notched plate specimen (R = 3 mm)

Grahic Jump Location
Fig. 5

Experimental results of mechanical fatigue tests with notched bar specimens normalized by nominal fatigue lives in DDS [22]

Grahic Jump Location
Fig. 6

Comparison of the experimental results and estimated strain range in the mechanical fatigue tests with notched bar specimens: (a) ρ = 1.6 mm, (b) ρ = 11.2 mm, and (c) ρ = 40.0 mm

Grahic Jump Location
Fig. 7

Comparison of N25% drop between experimental results and the results predicted by various strain range estimation methods in the mechanical fatigue tests with notched bar specimens

Grahic Jump Location
Fig. 8

Comparison of N1mm crack between experimental results and the results predicted by various strain range estimation methods in the mechanical fatigue tests with notched bar specimens

Grahic Jump Location
Fig. 9

Comparison of the accumulated conservativeness in the prediction procedure for fatigue life by DDS

Grahic Jump Location
Fig. 10

Relationship between the experimental number of cycles corresponding to crack length on the surface reaching 1 mm and estimated strain range in thermal fatigue test with notched plate specimen

Grahic Jump Location
Fig. 11

Comparison of N1mm crack between experimental results and predictions by various strain range estimation methods in thermal fatigue test with notched plate specimen

Grahic Jump Location
Fig. 12

Relationship of the normalized stress (σepe) and normalized strain (ɛepe)

Grahic Jump Location
Fig. 13

Situations of the plastic strain at the horizontal cross section calculated by inelastic FEA

Grahic Jump Location
Fig. 14

Concept of the SRL method

Grahic Jump Location
Fig. 15

Concept of the simple elastic follow-up method

Grahic Jump Location
Fig. 16

Illustration of the strain concentration factor based on the elastic follow-up concept employed by the JSME FR code

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In