Effect of Variable Amplitude Blocks’ Ordering on the Functional Fatigue of Superelastic NiTi Wires

Soul, H.; Yawny, A.

doi:10.1007/s40830-017-0126-z

Cited by 3 publications

(5 citation statements)

References 26 publications

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“…Variable amplitude loading involves load/deformation cycles of nonzero mean stresses/strains. Soul and Yawny, (2017) analysed the effects of different strain amplitudes following different loading sequences to study the fatigue of NiTi wires under displacement-controlled condition. They reported different evolution patterns of residual strain under various loading sequences.…”

Section: Structural Fatigue Of Stents/implants For Biomedical Applicationsmentioning

confidence: 99%

Advances in enhancing structural and functional fatigue resistance of superelastic NiTi shape memory alloy: A Review

Nargatti

Ahankari

2021

Journal of Intelligent Material Systems and Structures

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Nitinol (NiTi), a shape memory alloy (SMA) of nickel and titanium, exhibits two unique properties: the shape memory effect and superelasticity. It is a material of choice for applications demanding extraordinary flexibility and motion. It is subjected to greater fatigue strains compared to ordinary metals. The structural and functional fatigue properties are important for assessing the fatigue life and reliability of the superelastic NiTi. The advances made in the experimental analysis to improve the structural and functional fatigue resistance of superelastic NiTi are reviewed in this paper. Various aspects of fatigue behaviour of NiTi in biomedical and cooling applications, along with fatigue failure mechanism, are elaborated under structural fatigue. Importance of functional fatigue and its connect with structural fatigue performance of NiTi is discussed citing recent research literature. Furthermore, the effect of processing parameters involved in additive manufacturing on the fatigue performance of NiTi is also discussed.

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Section: Structural Fatigue Of Stents/implants For Biomedical Applicationsmentioning

confidence: 99%

Advances in enhancing structural and functional fatigue resistance of superelastic NiTi shape memory alloy: A Review

Nargatti

Ahankari

2021

Journal of Intelligent Material Systems and Structures

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“…On the one hand, this allows studying the effect of loading history on the functional fatigue of SMA, that is necessary for the physical substantiation and building of SMA fatigue failure models under the variable amplitude loading. On the other hand, the features of functional behavior at variable amplitude loading are important for the design of models of structural fatigue of alloys (Soul H., Yawny A., 2017).…”

Section: Materials and Experimental Setupmentioning

confidence: 99%

“…Most structures and structural elements made of SMA operate under variable amplitude loading at real conditions. However, there exist a few studies regarding the effect of load sequence (Soul and Yawny 2015; Mahtabi at al., 2018) and variable amplitude loading (Soul and Yawny, 2017;Mahtabi et al, 2018) on SMA functional fatigue. In particular, there was studied the effect of various amplitude block loading history under the controlled crosshead displacement on the functional properties of pseudoelastic NiTi alloy (Soul and Yawny, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…However, there exist a few studies regarding the effect of load sequence (Soul and Yawny 2015; Mahtabi at al., 2018) and variable amplitude loading (Soul and Yawny, 2017;Mahtabi et al, 2018) on SMA functional fatigue. In particular, there was studied the effect of various amplitude block loading history under the controlled crosshead displacement on the functional properties of pseudoelastic NiTi alloy (Soul and Yawny, 2017). These blocks were applied with an increasing amplitude sequence, a decreasing amplitude sequence, and interleaved amplitudes.…”

Section: Introductionmentioning

confidence: 99%

“…It was shown that the loading type, namely, the block with increasing or decreasing amplitude sequence affects significantly on the residual strain evolution. The linear damage rule cannot be not applied completely to the test full austenite partial martensite (FAPM) cycles, for which the decreasing ordering sequence resulted in lower values of maximum residual drift (Soul and Yawny, 2017).…”

Section: Introductionmentioning

confidence: 99%

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Functional Behavior of Pseudoelastic NiTi Alloy Under Variable Amplitude Loading

Iasnii

Ясній

Lapusta

et al. 2020

Acta Mechanica Et Automatica

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Cyclic loading of superelastic NiTi shape memory alloy (SMA) causes forward and reverse austenite–martensіte transformations, and also increases the volume of stabilized martensite. This appears in the change of stress-strain curve form, the decrease of dissipation energy, and increase of residual strain, that is, named transformation ratcheting. In real structures, the SMA components in most cases are under the action of variable amplitude loading. Therefore, it is obvious that the loading history will influence the functional fatigue. In the present work, the effect of stress ratio on the functional properties of superelastic NiTi shape memory alloy under variable amplitude loading sequence with two blocks was investigated. The studies were carried out under the uniaxial tension of cylindrical specimens under load-full unload and load-part unload. The change of residual strain, strain range, dissipation, and cumulative dissipation energy density of NiTi alloy related to load sequences are discussed. Under both stress ratios, the residual strain in NiTi alloy is increased depending on the number of loading cycles on the high loading block that is similar to the tests at constant stress or strain amplitude. An unusual effect of NiTi alloy residual strain reduction with the number cycles is found at a lower block loading. There was revealed the effect of residual strain reduction of NiTi alloy on the number of loading cycles on the lower amplitude block. The amount of decrement of the residual strain during a low loading block is approximately equal to the reversible part of the residual strain due to the stabilized martensite. The decrease of the residual strain during the low loading block is approximately equal to the reversible part of residual strain due to the stabilized martensite. A good correlation of the effective Young’s modulus for both load blocks with residual strain, which is a measure of the volume of irreversible martensite, is observed.

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Load sequence effects and variable amplitude fatigue of superelastic NiTi

Mahtabi

Stone

Shamsaei

2018

International Journal of Mechanical Sciences

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Effect of Variable Amplitude Blocks’ Ordering on the Functional Fatigue of Superelastic NiTi Wires

Cited by 3 publications

References 26 publications

Advances in enhancing structural and functional fatigue resistance of superelastic NiTi shape memory alloy: A Review

Advances in enhancing structural and functional fatigue resistance of superelastic NiTi shape memory alloy: A Review

Functional Behavior of Pseudoelastic NiTi Alloy Under Variable Amplitude Loading

Load sequence effects and variable amplitude fatigue of superelastic NiTi

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