High-Strain Multiaxial Fatigue

1982 ◽  
Vol 104 (3) ◽  
pp. 165-173 ◽  
Author(s):  
F. Ellyin ◽  
B. Valaire
Keyword(s):  
Fatigue Life ◽  
High Strain ◽  
Low Cycle Fatigue ◽  
Fatigue Tests ◽  
Medium Carbon Steel ◽  
Multiaxial Fatigue ◽  
Cycle Fatigue ◽  
Medium Carbon ◽  
Plastic Components ◽  
Principal Strains

The aim of this investigation was to develop a method for the prediction of the high-strain multiaxial fatigue life (low-cycle fatigue) of a steel, based on high-strain uniaxial fatigue data. In this study, thinwalled cylindrical specimens were subjected to fully reversed high biaxial strains using differential pressure and axial load. The directions of the principal strains were maintained parallel and perpendicular to the specimen axes. Five different strain ratios were investigated covering both the inphase and fully out-of-phase conditions. The material selected for this investigation was a medium carbon steel; C-1018. It was found that a maximum principal strain theory, based on the plastic components of the applied strains, taking into account the strain in the thickness direction, resulted in a correlation between the biaxial and uniaxial results which was either good or conservative. Under inphase conditions the low-cycle fatigue life could be predicted using Nf = Nf0 a(ε1+ε2) and under fully out-of-phase conditions using Nf = Nf0 aε1 where ε1 and ε2 are the ordered applied plastic strains and the constants “Nf0” and “a” are obtained from uniaxial high-strain fatigue tests.

Probabilistic Model of the Multiaxial Low-Cycle Fatigue Life Prediction

2012 ◽  
Vol 479-481 ◽  
pp. 2135-2140
Author(s):  
Lei Wang ◽  
Tian Zhong Sui ◽  
Hang Zhao ◽  
En Guo Men
Keyword(s):  
Fatigue Life ◽  
Carbon Steel ◽  
Probabilistic Model ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Medium Carbon Steel ◽  
Multiaxial Fatigue ◽  
Fatigue Life Prediction ◽  
Cycle Fatigue ◽  
Medium Carbon

First, several widely used models of the multiaxial low-cycle fatigue life prediction based on the critical plane approach were presented in this paper, and the predicted results of these models for a medium carbon steel under the condition of multiaxial low-cycle fatigue loading were compared. Second, the stochastic expressions and probability density function curves of the fatigue performance parameters were obtained by probabilistic analysis of the medium carbon steel fatigue data. Finally, the probabilistic model of the multiaxial fatigue life prediction was simulated by Monte Carlo Method, which should provide a basis for the reliability analysis of engineering components subjected to the multiaxial complex loads.

Effect of Notched Parameters on Low Cycle Fatigue Life of Shaft under Bending-Torsional Loading

2011 ◽  
Vol 488-489 ◽  
pp. 166-169
Author(s):  
Ping Ma ◽  
You Tang Li
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Testing Machine ◽  
Medium Carbon Steel ◽  
Cycle Fatigue ◽  
Medium Carbon ◽  
Fatigue Design ◽  
Tip Radius ◽  
Special Clamp

A special clamp for fatigue of shaft under bending-torsion that used on the fatigue machine is designed and manufactured. For the medium carbon steel, the low-cycle fatigue experiments of shaft with annular notch under bending-torsion have been made on Shimadzu EHF-EM100kN high-frequency electro-hydraulic fatigue testing machine. Through experiments and analysis, the effects of tip radius, depth and open angle of notch on low cycle fatigue life of shaft with annular notch under bending-torsion are obtained. The method and results will play an important role on the fatigue life prediction and anti-fatigue design.

scholarly journals Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4070
Author(s):  
Andrea Karen Persons ◽  
John E. Ball ◽  
Charles Freeman ◽  
David M. Macias ◽  
Chartrisa LaShan Simpson ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Prediction Models ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Wearable Sensors ◽  
Fatigue Tests ◽  
Proof Of Concept ◽  
Cycle Fatigue ◽  
Wearable Sensing ◽  
Failure Data

Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from “bench to bedside,” fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.

scholarly journals Impact of Temperature on Low-Cycle Fatigue Characteristics of the HR6W Alloy

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6741
Author(s):  
Grzegorz Junak ◽  
Anżelina Marek ◽  
Michał Paduchowicz
Keyword(s):  
Fatigue Life ◽  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Tests ◽  
Total Strain ◽  
Cycle Fatigue ◽  
Fatigue Characteristics

This paper presents the results of tests conducted on the HR6W (23Cr-45Ni-6W-Nb-Ti-B) alloy under low-cycle fatigue at room temperature and at 650 °C. Fatigue tests were carried out at constant values of the total strain ranges. The alloy under low-cycle fatigue showed cyclic strengthening both at room temperature and at 650 °C. The degree of HR6W strengthening described by coefficient n’ was higher at higher temperatures. At the same time, its fatigue life Nf at room temperature was, depending on the range of total strain adopted in the tests, several times higher than observed at 650 °C.

scholarly journals Multiaxial fatigue life estimation in low-cycle fatigue regime including the mean stress effect

2018 ◽  
Vol 165 ◽  
pp. 16002
Author(s):  
Daniela Scorza ◽  
Andrea Carpinteri ◽  
Giovanni Fortese ◽  
Camilla Ronchei ◽  
Sabrina Vantadori ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Equivalent Strain ◽  
Mean Value ◽  
Multiaxial Fatigue ◽  
Stress Effect ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Structural Components ◽  
Mean Stress Effect

The goal of the present paper is to discuss the reliability of a strain-based multiaxial Low-Cycle Fatigue (LCF) criterion in estimating the fatigue lifetime of metallic structural components subjected to multiaxial sinusoidal loading with zero and non-zero mean value. Since it is well-known that a tensile mean normal stress reduces the fatigue life of structural components, three different models available in the literature are implemented in the present criterion in order to take into account the above mean stress effect. In particular, such a criterion is formulated in terms of strains by employing the displacement components acting on the critical plane and, then, by defining an equivalent strain related to such a plane. The Morrow model, the Smith-Watson-Topper model and the Manson-Halford model are applied to define such an equivalent strain. The effectiveness of the new formulations is evaluated through comparison with some experimental data reported in the literature, related to biaxial fatigue tests performed on metallic specimens under in-and out-of-phase loadings characterised by non-zero mean stress values.

Low Cycle Fatigue Properties of FGH720Li Superalloy

2021 ◽  
Vol 1035 ◽  
pp. 292-296
Author(s):  
Zi Chao Peng ◽  
Jun Ying Sheng ◽  
Xu Qing Wang ◽  
Yue Tang
Keyword(s):  
Fatigue Life ◽  
Powder Metallurgy ◽  
Applied Stress ◽  
Low Cycle Fatigue ◽  
Influencing Factor ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Nickel Base Superalloy ◽  
Loading Frequency ◽  
Cycle Fatigue

Low cycle fatigue (LCF) properties of a powder metallurgy(PM) nickel base superalloy FGH720Li were systematically studied in this work, including smooth LCF and notched LCF tested at various temperatures and different stress. The relationship between the fatigue life and applied stress was analyzed both for smooth fatigue and notch fatigue tests. The effects of loading frequency and stress ratio on LCF behavior were also studied. As an important influencing factor of the fatigue life in powder metallurgy superalloy, the effect of inclusions on LCF life was also investigated. The results showed that the fatigue properties of FGH720Li alloy was excellent, when tested at the temperature of 450°C and applied stress of 1230MPa, the fatigue life could exceed 5×104 cycles. When tested at 650°C and 1150MPa, the average fatigue life was still beyond 2×105 cycles.

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