Different criteria of equivalent plastic-strain range in the theory of low-cycle fatigue

1982 ◽  
Vol 14 (12) ◽  
pp. 1579-1583 ◽  
Author(s):  
A. A. Movchan
Keyword(s):  
Plastic Strain ◽  
Low Cycle Fatigue ◽  
Equivalent Plastic Strain ◽  
Strain Range ◽  
Cycle Fatigue ◽  
Plastic Strain Range

scholarly journals Thermal-Stress and Low-Cycle Fatigue Data on Typical Materials

1965 ◽  
Author(s):  
K. E. Horton ◽  
J. M. Hallander ◽  
D. D. Foley
Keyword(s):  
Plastic Strain ◽  
Low Cycle Fatigue ◽  
Mechanical Strain ◽  
Thermal Strain ◽  
Strain Range ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Ferrous Alloys ◽  
Plastic Strain Range ◽  
Analysis Of Results

This paper presents the results of low-cycle-fatigue tests wherein either thermal strain or mechanical strain was the independent variable. The materials investigated were primarily ferrous alloys for use in nuclear reactors. The analysis of results was based on plastic-strain-range measurements which could be made reproducibly in the 2 × 10−5 range. Graphs of plastic strain range versus cycles to failure were often found to be independent of large variations in temperature and cycle time. The results from thermal-fatigue and constant-temperature-fatigue tests were usually indistinguishable on these graphs, suggesting that identical metallurgical phenomena occurred in each type of test.

scholarly journals Limit, Shakedown and Ratchet Analyses of Defective Pipeline Under Internal Pressure and Cyclic Thermal Loading

2011 ◽  
Author(s):  
Weihang Chen ◽  
Haofeng Chen ◽  
Tianbai Li ◽  
James Ure
Keyword(s):  
Plastic Strain ◽  
Internal Pressure ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Collapse Mechanism ◽  
Cycle Fatigue ◽  
Matching Method ◽  
Plastic Strain Range ◽  
Fatigue Assessment ◽  
Linear Matching Method

In this study, the limit load, shakedown and ratchet limit of a defective pipeline subjected to constant internal pressure and a cyclic thermal gradient are analyzed. Ratchet limit and maximum plastic strain range are solved by employing the new Linear Matching Method (LMM) for the direct evaluation of the ratchet limit. Shakedown and ratchet limit interaction diagrams of the defective pipeline identifying the regions of shakedown, reverse plasticity, ratcheting and plastic collapse mechanism are presented and parametric studies involving different types and dimensions of part-through slot in the defective pipeline are investigated. The maximum plastic strain range over the steady cycle with different cyclic loading combinations is evaluated for a low cycle fatigue assessment. The location of the initiation of a fatigue crack for the defective pipeline with different slot type is determined. The proposed linear matching method provides a general-purpose technique for the evaluation of these key design limits and the plastic strain range for the low cycle fatigue assessment. The results for the defective pipeline shown in the paper confirm the applicability of this procedure to complex 3-D structures.

Definition of Damage Parameter in Low-Cycle Fatigue of Gray Cast Iron

2007 ◽  
Vol 345-346 ◽  
pp. 367-370 ◽  
Author(s):  
Keum Oh Lee ◽  
Soon Bok Lee
Keyword(s):  
Cast Iron ◽  
Plastic Strain ◽  
Gray Cast Iron ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Damage Parameter ◽  
Gray Cast ◽  
Graphite Flake ◽  
Cycle Fatigue ◽  
Plastic Strain Range

Gray cast iron shows large asymmetrical features by the graphite flake when tensile and compressive stresses are applied. The plastic strain rage which is used in low-cycle fatigue life prediction by many researchers is hardly defined and gives very different values by the Standards in this case. From the results of this study, it is not reliable to use the plastic strain range as a low-cycle fatigue damage parameter. Therefore, the plastic strain energy density which is uniquely defined was suggested as a damage parameter and it showed good correlation in low-cycle fatigue in gray cast iron.

scholarly journals On Shakedown, Ratchet and Limit Analyses of Defective Pipeline

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Haofeng Chen ◽  
Weihang Chen ◽  
Tianbai Li ◽  
James Ure
Keyword(s):  
Plastic Strain ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Collapse Mechanism ◽  
Cycle Fatigue ◽  
Matching Method ◽  
Direct Evaluation ◽  
Plastic Strain Range ◽  
Fatigue Assessment ◽  
Linear Matching Method

In this study, the limit load, shakedown, and ratchet limit of a defective pipeline subjected to constant internal pressure and a cyclic thermal gradient are analyzed. Ratchet limit and maximum plastic strain range are solved by employing the new linear matching method (LMM) for the direct evaluation of the ratchet limit. Shakedown and ratchet limit interaction diagrams of the defective pipeline identifying the regions of shakedown, reverse plasticity, ratcheting, and plastic collapse mechanism are presented, and parametric studies involving different types and dimensions of part-through slot in the defective pipeline are investigated. The maximum plastic strain range over the steady cycle with different cyclic loading combinations is evaluated for a low cycle fatigue assessment. The location of the initiation of a fatigue crack for the defective pipeline with different slot type is determined. The proposed linear matching method provides a general-purpose technique for the evaluation of these key design limits and the plastic strain range for the low cycle fatigue assessment. The results for the defective pipeline shown in the paper confirm the applicability of this procedure to complex 3-D structures.

The low Cycle Fatigue Behavior of Three advanced Nickel-Base Eutectic Composites

1981 ◽  
Vol 12 ◽  
Author(s):  
T. Ishii ◽  
D. J. Duquette ◽  
N. S. Stoloff
Keyword(s):  
Plastic Strain ◽  
Linear Relation ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Metals And Alloys ◽  
Cycle Fatigue ◽  
Plastic Strain Range ◽  
Nickel Base

AbstractThe low cycle fatigue behavior at 25°C and 825°C of three advanced nickel-base eutectics is described. Fatigue lives are shown to obey a linear relation with plastic strain range (Coffin-Manson relation) but lives are much lower than are observed for conventional metals and alloys. Cyclic hardening and softening were observed in each alloy at 25 °C; however, this behavior differs from the classical saturation behavior observed with isotropic materials.

Characteristics of Complementary Plastic Energy Produced by Hysteresis Curves and Analyses of Microstructures in Fatigued Metals

2007 ◽  
Vol 340-341 ◽  
pp. 513-518
Author(s):  
Hiroshi Matsuno
Keyword(s):  
Plastic Strain ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Hysteresis Curve ◽  
Final Conclusion ◽  
Cycle Fatigue ◽  
Plastic Strain Range ◽  
Plastic Energy ◽  
A Cell ◽  
Number Of Cells

Experimental characteristics of complementary plastic energy produced by a stress-strain hysteresis curve at a saturated stage in low cycle fatigue are investigated for some steels, and mechanical models for analyzing microstructures of fatigued metals are discussed. As a result, it is found that volume of a cell is varied in inverse proportion to plastic strain range: the density of cells is in proportion to plastic strain range. Consequently, the total number of cells is proportional to plastic strain range. This final conclusion is similar to Winter's opinion concerning persistent slip band structures in high cycle fatigue [1] where, although wall spacing of a cell is invariable and inde-pendent of plastic strain range, a region occupied by persistent slip bands increases proportionally to plastic strain range and consequently the number of cells is in proportion to plastic strain range.

Low-Cycle Fatigue Life of Continuously Cyclic-Hardening Material

2020 ◽  
Author(s):  
Zhong Zhang ◽  
Xijia Wu
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Root Mean Square ◽  
Low Cycle Fatigue ◽  
Cyclic Hardening ◽  
Mean Square ◽  
Cycle Fatigue ◽  
Fatigue Crack Nucleation ◽  
Hardening Material ◽  
Plastic Strain Range

Abstract A general fatigue life equation is derived by modifying the Tanaka-Mura-Wu dislocation pile-up model for variable strain-amplitude fatigue processes, where the fatigue crack nucleation life is expressed in terms of the root mean square of plastic strain range. Low-cycle fatigue tests were conducted on an austenitic stainless steel. at 400°C and 600°C, the material exhibits continuously cyclic-hardening behaviour. The root mean square of plastic strain ranges is evaluated from the experimental data for each test condition at strain rates ranging from 0.0002/s to 0.02/s. The variable-amplitude Tanaka-Mura-Wu model is found to be in good agreement with the LCF data, which effectively proves Miner’s rule on the stored plastic strain energy basis.

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