Frequency and Hold-Time Effects on Low Cycle Fatigue Life of Notched Specimens at Elevated Temperature

This paper describes the frequency and hold-time effects on high temperature low cycle fatigue for round notched specimens. Unnotched and notched specimens having different elastic stress concentration factors were fatigued under triangular and trapezoidal stress waves at frequencies ranging from 5 Hz to 0.0001 Hz at 873 K. The three specific fracture characteristics were observed: cycle dependent, time dependent, and cycle-time dependent. The respective notch sensitivity occurred in the respective fracture regime. The fatigue life of notched specimens was predicted from the elastic-plastic-creep cyclic FEM analysis using the linear damage rule and the strain range partitioning rule. Both the life prediction methods predicted the creep-fatigue life within almost a factor of two scatter band.

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Frequency and hold-time effects on low cycle fatigue life of notched specimens at elevated temperatureSakane, M., Ohnami, M., Awaya, T. and Shirafuji, N. J. Eng. Mater. Technol. (Trans. ASME) Jan. 1989 111, (1), 54–60

International Journal of Fatigue ◽

10.1016/0142-1123(89)90425-8 ◽

1989 ◽

Vol 11 (4) ◽

pp. 287-287

Keyword(s):

Fatigue Life ◽

Low Cycle Fatigue ◽

Hold Time ◽

Cycle Fatigue ◽

Time Effects ◽

Notched Specimens ◽

Trans Asme

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Investigation on Low Cycle Fatigue Life of SC Notched Specimens

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.97-101.449 ◽

2010 ◽

Vol 97-101 ◽

pp. 449-452

Author(s):

Ping Zhao ◽

Qing Hua He ◽

Wei Li

Keyword(s):

Fatigue Life ◽

Stress Ratio ◽

Low Cycle Fatigue ◽

Strain Range ◽

Mean Stress ◽

Cycle Fatigue ◽

Total Strain Range ◽

Notched Specimens ◽

Orientation Function ◽

Fatigue Notch Factor

A low cycle fatigue life (LCF) prediction model for nickel-based single crystal (SC) is presented based on the LCF experiments of notched specimens. Fatigue notch factor is adopted to reflect the influence of notch shape on LCF. Orientation function is adopted to modify total strain range and eliminate the influence of orientation on LCF. Cycle stress ratio is adopted to reflect the influence of mean stress and cycle character on LCF. The predicted results shows that all the data are in the factor of 2.1 scatter band, which means that the model proposed in this work is reasonable.

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Influence of Hold-Time and Temperature on the Low-Cycle Fatigue of Incoloy 800

Journal of Engineering for Industry ◽

10.1115/1.3428273 ◽

1972 ◽

Vol 94 (3) ◽

pp. 930-934 ◽

Cited By ~ 7

Author(s):

C. E. Jaske ◽

H. Mindlin ◽

J. S. Perrin

Keyword(s):

Fatigue Life ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Compressive Strain ◽

Hold Time ◽

Strain Range ◽

Cyclic Fatigue ◽

Cycle Fatigue ◽

Incoloy 800 ◽

Strain Cycling

A study has been conducted to determine the low-cycle fatigue behavior of solution-annealed Incoloy 800 bar at temperatures from 800–1400 deg F. The experimental work included evaluation of specimens under both continuous, completely reversed strain cycling and under strain cycling with hold time periods at the strain limits. At 1000, 1200, and 1400 deg F, it was found that 10-min hold-times at the tensile strain limit during every cycle significantly reduced the cyclic fatigue life compared to continuous cycling. However, there was little reduction in cyclic fatigue life when 10-min hold-times were introduced at the compressive strain limits or at both the tensile and compressive limits. The ratio of hold-time cyclic fatigue life to no-hold-time cyclic fatigue life decreased as the length of hold time increased (at constant total strain range) and as the magnitude of strain range decreased (at constant hold-time length).

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Interaction Diagram for Time Dependent Fatigue

Journal of Engineering Materials and Technology ◽

10.1115/1.3225658 ◽

1983 ◽

Vol 105 (4) ◽

pp. 273-279 ◽

Cited By ~ 2

Author(s):

V. M. Radhakrishnan

Keyword(s):

Fatigue Life ◽

Loading Condition ◽

Low Cycle Fatigue ◽

Time Dependent ◽

Cycle Fatigue ◽

Interaction Diagram ◽

Cycle Dependent ◽

Propagation Stage ◽

Dependent Interaction ◽

Strain Hold

Interaction of fatigue with corrosion and creep has been analyzed through a parameter [Fi] introduced at the crack propagation stage. Assuming the effect of corrosion and creep to become dominant below a certain frequency, a model is proposed which is able to explain the stress-hold and the strain-hold effects on the fatigue life in time dependent fatigue. Beyond a certain period stress-hold leads to time-dependent and strain-hold leads to cycle-dependent interaction life. By suitably evaluating the parameter [Fi], life under any type of loading condition can be estimated. Based on the parameter, an interaction diagram is proposed for predicting the fatigue life in time dependent high temperature low cycle fatigue.

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A Study on the Notch Effect on the Low Cycle Fatigue of Metals in Creep-Fatigue Interacting Conditions at Elevated Temperature

Journal of Engineering Materials and Technology ◽

10.1115/1.3225629 ◽

1983 ◽

Vol 105 (2) ◽

pp. 75-80 ◽

Cited By ~ 9

Author(s):

M. Sakane ◽

M. Ohnami

Keyword(s):

Elastic Stress ◽

Low Cycle Fatigue ◽

Hold Time ◽

Cycle Fatigue ◽

Time Effects ◽

Notched Specimen ◽

Notched Specimens ◽

Creep Fatigue ◽

Neuber's Rule ◽

Modified Equation

Frequency and hold-time effects on fatigue lives of cylindrical notched specimens of SUS 316 stainless steel were studied at 600° C in air. From the tests, the following conclusions were obtained: Neuber’s rule, as used in the ASME N-47 Code, predicts very conservatively the life of notched specimens in tests without a hold-time. But it gives a nonconservative estimate for the reduction in the life of the material by the introduction of a hold-time. An empirical formula of a “frequency-elastic stress concentration factor modified equation” was obtained by analysing the experimental data. It predicts accurately the life of the notched specimen tested at different frequencies.

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The Effect of Strain Rate on Low Cycle Fatigue Life with Hold Time for USC Candidate Rotor Material

Fatigue of Materials ◽

10.1002/9781118013373.ch14 ◽

2010 ◽

pp. 217-229

Author(s):

Kuk-cheol Kim ◽

Byeong-ook Kong ◽

Min-soo Kim ◽

Sung-tae Kang

Keyword(s):

Fatigue Life ◽

Strain Rate ◽

Low Cycle Fatigue ◽

Hold Time ◽

Cycle Fatigue

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Multiaxial Low Cycle Fatigue Life Prediction at 300 °C Using Equivalent Strain Appoach

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.361-363.1669 ◽

2011 ◽

Vol 361-363 ◽

pp. 1669-1672

Author(s):

Wen Xiao Zhang ◽

Guo Dong Gao ◽

Guang Yu Mu

Keyword(s):

Fatigue Life ◽

Life Prediction ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Strain Range ◽

Cyclic Fatigue ◽

Equivalent Strain ◽

Multiaxial Fatigue ◽

Fatigue Life Prediction ◽

Cycle Fatigue

The low cycle fatigue behavior was experimentally studied with the 3-dimension notched LD8 aluminum alloy specimens at 300°C. The 3- dimension stress-strain responses of specimens were calculated by means of the program ADINA. The multiaxial fatigue life prediction was carried out according to von Mises’s equivalent theory. The results from the prediction showed that the equivalent strain range can be served as the valid mechanics for predicting multiaxial high temperature and low cyclic fatigue life.

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