Low-Cycle Fatigue Behavior of Internally Pressurized Boxes

1967 ◽  
Vol 89 (3) ◽  
pp. 427-435 ◽  
Author(s):  
M. R. Gross ◽  
R. E. Heise
Keyword(s):  
Aluminum Alloy ◽  
Yield Strength ◽  
Thick Plate ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Complex Structures ◽  
Cycle Fatigue ◽  
Total Strain Range ◽  
Structural Applications

One phase of a continuing study of the low-cycle fatigue behavior of metals for deep submergence structural applications involves the validity of simple specimen results when applied to complex structures. As a part of this study, the low-cycle fatigue performance of twelve internally pressurized boxes was investigated. The boxes were constructed from 1-in-thick plate of six materials consisting of three steels, one aluminum alloy, and two titanium alloys. The boxes were cyclically pressurized at peak nominal stresses up to about 80 percent of the yield strength of the base metal. The results are compared with data previously obtained for simple laboratory specimens. The results of the box tests tend to confirm two general conclusions reached previously from simple specimen tests, that is: (1) Increases in low-cycle fatigue strength for a given life are not commensurate with increases in yield strength, and (2) low-cycle fatigue life is closely related to total strain range and appears to be independent of both structural metal and strength level in the life range of 1000 to 30,000 cycles.

Low Cycle Fatigue Characteristics of a Low-Thermal Expansion, High Strength Alloy (HAYNES 242 Alloy)

2011 ◽  
Author(s):  
L. M. Pike ◽  
S. K. Srivastava
Keyword(s):  
Thermal Expansion ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
High Strength ◽  
Wave Form ◽  
Cycle Fatigue ◽  
Total Strain Range ◽  
Low Thermal Expansion ◽  
Long Range Ordering

HAYNES® 242® alloy, based primarily on the Ni-25Mo-8Cr system, derives its low thermal expansion characteristics from its composition and its high strength concomitant with high ductility from a long-range ordering reaction upon an aging heat treatment. This combination has enabled the alloy continually to find a challenging range of applications in the aerospace industry at up to 1300°F (704°C). These include seal rings, containment rings, duct segments, casings, rocket nozzles, etc. In conjunction with the creep strength and environmental resistance, the low cycle fatigue (LCF) behavior is an important material property affecting the service life of 242 alloy components. The low cycle fatigue behavior of 242 alloy was studied under fully reversed strain-controlled mode at 800°F (427°C), 1000°F (538°C), 1200°F (649°C) and 1400°F (760°C) using a triangular wave form with a frequency of 0.33 Hz. Results are presented in terms of cycles to crack initiation and failure. The magnitudes of fatigue lives at total strain range ≤ 0.7% at 800, 1000 and 1200°F are significantly greater than those of solid solution strengthened alloys. Additionally, stress-controlled LCF tests were performed at 1200°F (649°C) on 242 alloy as well as 909 alloy (for comparison). The paper will discuss the results of these two test programs.

Low Cycle Fatigue of Alloy 617 at 850 °C and 950 °C

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
J. K. Wright ◽  
L. J. Carroll ◽  
J. A. Simpson ◽  
R. N. Wright
Keyword(s):  
Strain Rate ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Solute Drag ◽  
Cycle Fatigue ◽  
Alloy 617 ◽  
Total Strain Range ◽  
Cycles To Failure

The low cycle fatigue behavior of Alloy 617 has been evaluated at 850 °C and 950 °C, the temperature range of particular interest for the intermediate heat exchanger on a proposed high-temperature gas-cooled nuclear reactor. Cycles to failure were measured as a function of total strain range and varying strain rate. Results of the current experiments compare well with previous work reported in the literature for a similar range of temperatures and strain rate. The combined data demonstrate a Coffin–Manson relationship, although the slope of the Coffin–Manson fit is close to −1 rather than the typically reported value of −0.5. At 850 °C and a strain rate of 10−3 /s Alloy 617 deforms by a plastic flow mechanism in low cycle fatigue and exhibits some cyclic hardening. At 950 °C for strain rates of 10−3–10−5 /s, Alloy 617 deforms by a solute drag creep mechanism during low cycle fatigue and does not show significant cyclic hardening or softening. At this temperature the strain rate has little influence on the cycles to failure for the strain ranges tested.

Low Cycle Fatigue Behavior of Alloy 800H Base Metal and Weldments at 700°C

2018 ◽  
Author(s):  
Seon-Jin Kim ◽  
Rando Tungga Dewa ◽  
Woo-Gon Kim ◽  
Eung-Seon Kim
Keyword(s):  
Base Metal ◽  
Deformation Behavior ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Fatigue Tests ◽  
Total Strain ◽  
Cycle Fatigue ◽  
Alloy 800H ◽  
Total Strain Range

Alloy 800H is currently being considered as one of the near-term candidate materials for design and construction of some major high temperature components of a very high temperature reactor (VHTR). System start-ups and shut-downs as well as power transients will produce low-cycle fatigue loadings of components. The aim of this work is to study the low cycle fatigue behavior of Alloy 800H base metal and weldments at 700°C. The weldment specimens were machined from gas tungsten arc welding (GTAW) butt-welded plate such that the loading direction was oriented transverse to the welding direction. Fully reversed total-strain controlled low-cycle fatigue tests have been performed at total strain ranges of 0.6, 0.9, 1.2 and 1.5%. For all the low-cycle fatigue tests, triangular test waveforms with a constant strain rate of 10−3/s were applied. Low-cycle fatigue testing was conducted in accordance with ASTM Standard E606 on servo-hydraulic test machines. And also, creep-fatigue experiments were carried out at 700°C employing 0.6% total strain range and 10−3/s strain rate using trapezoidal waveform with tension hold time. The main focus is to characterize the low-cycle fatigue properties for Alloy 800H weldment specimens from the cyclic deformation behavior and fatigue fracture behavior. The cyclic deformation behavior was influenced by total strain range and material property. The fatigue life was decreased with increasing the total strain range for both base metal and weldment. However, the lives of weldment specimens have a longer life than that of base metal at lower total strain ranges. It was also observed that creep effects play a significant role in fatigue life reduction.

LOW CYCLE FATIGUE BEHAVIOR AND LIFE PREDICTION OF A CAST COBALT-BASED SUPERALLOY

2012 ◽  
Vol 06 ◽  
pp. 251-256
Author(s):  
HO-YOUNG YANG ◽  
JAE-HOON KIM ◽  
KEUN-BONG YOO
Keyword(s):  
Fatigue Life ◽  
Strain Energy ◽  
Life Prediction ◽  
Prediction Models ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Total Strain ◽  
Cycle Fatigue ◽  
Total Strain Range ◽  
Different Temperatures

Co -base superalloys have been applied in the stationary components of gas turbine owing to their excellent high temperature properties. Low cycle fatigue data on ECY-768 reported in a companion paper were used to evaluate fatigue life prediction models. In this study, low cycle fatigue tests are performed as the variables of total strain range and temperatures. The relations between plastic and total strain energy densities and number of cycles to failure are examined in order to predict the low cycle fatigue life of Cobalt-based super alloy at different temperatures. The fatigue lives is evaluated using predicted by Coffin-Manson method and strain energy methods is compared with the measured fatigue lives at different temperatures. The microstructure observing was performed for how affect able to low-cycle fatigue life by increasing the temperature.

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

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.

High-Temperature Low-Cycle Fatigue Behavior of MarBN at 600 °C

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Richard A. Barrett ◽  
Eimear M. O'Hara ◽  
Padraic E. O'Donoghue ◽  
Sean B. Leen
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Material Model ◽  
Cyclic Softening ◽  
Cyclic Strength ◽  
Cycle Fatigue ◽  
Viscoplastic Material

This paper presents the high-temperature low-cycle fatigue (HTLCF) behavior of a precipitate strengthened 9Cr martensitic steel, MarBN, designed to provide enhanced creep strength and precipitate stability at high temperature. The strain-controlled test program addresses the cyclic effects of strain-rate and strain-range at 600 °C, as well as tensile stress-relaxation response. A recently developed unified cyclic viscoplastic material model is implemented to characterize the complex cyclic and relaxation plasticity response, including cyclic softening and kinematic hardening effects. The measured response is compared to that of P91 steel, a current power plant material, and shows enhanced cyclic strength relative to P91.

Low-Cycle Fatigue under Biaxial Stress

1974 ◽  
Vol 188 (1) ◽  
pp. 657-671 ◽  
Author(s):  
M. W. Parsons ◽  
K. J. Pascoe
Keyword(s):  
Austenitic Steel ◽  
Abrupt Change ◽  
Low Cycle Fatigue ◽  
Axial Loading ◽  
Strain Range ◽  
Fatigue Behaviour ◽  
Biaxial Stress ◽  
Cycle Fatigue ◽  
Biaxial Strain ◽  
Total Strain Range

The low-cycle fatigue behaviour of a ferritic and an austenitic steel have been studied under various conditions of reversed biaxial strain. These cyclically softened and hardened respectively. In all cases, relationships of the form were found between total strain range Δε t and life Nf for lives in the range 102−105 cycles, with an abrupt change of β at intermediate lives. Variation of state of strain affected both β and κ. Various theories for the correlation of fatigue behaviour under multi-axial loading have been reviewed and compared with these results. None was found to account adequately for the effect of straining régime with the materials tested.

Low Cycle Fatigue Behavior of a New Type of Zircaloy Material

2011 ◽  
Vol 80-81 ◽  
pp. 788-791
Author(s):  
Wei Wei Yu ◽  
Fei Xue ◽  
Xin Ming Meng ◽  
Lei Lin
Keyword(s):  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Cycle Fatigue ◽  
Fatigue Lifetime ◽  
Softening Behavior ◽  
New Type

To investigate the property of a new type of Zircaloy material, a low cycle fatigue (LCF) test has been performed at room temperature (RT) and 375°C. Results show that the new alloy generally displays cyclic hardening followed by a continuous softening behavior. Fatigue lifetime curves as a function of strain range imply that the new alloy has a nearly same lifetime than that of Zr-4 at RT, and superior than that at 375°C.

Effect of Creep in Low-Cycle Fatigue of Pressure Vessel Steel

1970 ◽  
Vol 92 (1) ◽  
pp. 67-73 ◽  
Author(s):  
J. Dubuc ◽  
A. Biron
Keyword(s):  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Fatigue Tests ◽  
Pressure Vessel Steel ◽  
Cycle Fatigue ◽  
Total Strain Range ◽  
Vessel Steel ◽  
The Mean ◽  
Mean Strain

Low-cycle fatigue tests have been carried out at 2 cpm on a pressure vessel steel at 350 deg C (662 deg F). The total strain range was fixed for each test and the minimum (or mean) strain in some cases was constant (zero minimum value), in others increased uniformly in time at a predetermined rate. It was found that variations in the mean strain up to 0.5 percent/hour had no significant influence on the results.

Notch Effect in Low-Cycle Fatigue at Elevated Temperatures—Life Prediction From Crack Initiation and Propagation Considerations

1986 ◽  
Vol 108 (4) ◽  
pp. 279-284 ◽  
Author(s):  
Masao Sakane ◽  
Masateru Ohnami
Keyword(s):  
Crack Initiation ◽  
Elevated Temperatures ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Notch Effect ◽  
Cycle Fatigue ◽  
Crack Initiation And Propagation ◽  
Total Strain Range ◽  
Notched Specimens ◽  
Initiation And Propagation

This paper describes the notch effect in low-cycle fatigue of an austenitic stainless steel SUS 304 at 873 K in air. Total strain range-controlled tests were carried out using a round unnotched and three round notched specimens. A prediction method for low-cycle fatigue lives of notched specimens was developed by predicting the crack initiation and propagation periods separately. To predict the former Neuber’s rule was applied and a nominal stress/strain criterion was developed to predict the latter. Failure lives, obtained by adding the two prediction lives, closely agree with observed failure lives.

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