Mechanical Behaviour and Phase Transition Mechanisms of a Shape Memory Alloy by Means of a Novel Analytical Model

Carpinteri, Andrea; Cocco, Vittorio Di; Fortese, Giovanni; Iacoviello, Francesco; Natali, S.; Ronchei, Camilla; Scorza, Daniela; Zanichelli, Andrea

doi:10.2478/ama-2018-0017

Cited by 9 publications

(3 citation statements)

References 15 publications

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“…This is due to the austenite‐martensite transformation 8 . After removing the external load, SMAs recover their original shape without any additional impact (due to the pseudoelastic effect 9 ) or after heating above a critical temperature (due to the shape memory effect) 10 . Shape recovery is due to the relatively low temperature of the austenite (which is stable at higher temperatures) transformation into martensite 11 .…”

Section: Introductionmentioning

confidence: 99%

Frequency effect on low‐cycle fatigue behavior of pseudoelastic NiTi alloy

Iasnii,

Krechkovska,

Budz

et al. 2024

Fatigue Fract Eng Mat Struct

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This study presents experimental results on the effect of loading frequency during low‐cycle fatigue on the fracture mechanism and properties of pseudoelastic NiTi wire. The uniaxial tensile tests were performed in stress‐controlled mode over the 0.1–10 Hz frequency range. It was shown that the number of cycles before specimen failure decreased with increasing frequency from 0.1 Hz to 1 Hz but increased at frequencies above 1 Hz. It was fractographically shown that fatigue striations were observed on the fracture surfaces of specimens tested at all loading frequencies. A new type of fatigue striations was described on fracture specimens tested at frequencies up to 1 Hz. They are characterized by different spacing between successive striations with a change in the slope of the fracture at the transitions between them. This feature may be associated with forward and reverse phase transformations during half‐periods of loading and unloading of nitinol.

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Section: Introductionmentioning

confidence: 99%

Frequency effect on low‐cycle fatigue behavior of pseudoelastic NiTi alloy

Iasnii,

Krechkovska,

Budz

et al. 2024

Fatigue Fract Eng Mat Struct

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“…Based on the empirical evidence of worldwide research in using materials with SME, technological methods of their processing in conjunction with the operational capabilities has supported the hypothesis of the need for thermal-force cycling in the pre-deformation state to be developed [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Improving the Models of Dynamics of Adaptively Controlled Elements and Drives Based on Functional Materials

Nikolaiev¹,

Polishchuk²,

Zadorozhna³

2020

Metallofiz. Noveishie Tekhnol.

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The investigation of thermo-mechanical processes in materials and elements with shape memory effect (SME) and the simulation of dynamics of elements and drives based on alloys with shape memory and taking into account the adaptation properties of material are carried out in order to develop adaptive-controlled thermomechanical drives or actuators, heat regulator and automation tools of technological processes. The effect of the thermal cycling modes and the magnitude of deformation, which induces the shape memory effect, on the level of reversibility of the deformation, the implementation of the effect of reversible shape memory, the magnitude of the excited force, and the recoverable deformation are investigated. A generalized dynamic model of a technical mechanism based on the elements with SME is developed. The model formally describes adaptive control of mechanism, based on which, the adaptation algorithms can be synthesized. The developed models can be used in the calculation and design of various thermomechanical drives and actuators, heat regulators, thermal compensators and damping devices based on elements from shape memory alloys, as well as in a synthesis of adaptive control algorithms of continuous and discrete classes in the terminal control, homing guidance and stabilization modes.

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“…The functional properties of the pseudoelastic SMA deteriorate under cyclic loading (Auricchio et al, 2004;Araya et al, 2008;Kang G., 2013;Vantadori et al, 2018). In particular, there is a significant decrease of recovered strain, recovery energy, dissipated energy, Young's modulus, direct transformation stress, and increased residual strain at strain-controlled and stress-controlled tests (Maletta, 2014;Kang G., 2013).…”

Section: Introductionmentioning

confidence: 99%

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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Mechanical Behaviour and Phase Transition Mechanisms of a Shape Memory Alloy by Means of a Novel Analytical Model

Cited by 9 publications

References 15 publications

Frequency effect on low‐cycle fatigue behavior of pseudoelastic NiTi alloy

Frequency effect on low‐cycle fatigue behavior of pseudoelastic NiTi alloy

Improving the Models of Dynamics of Adaptively Controlled Elements and Drives Based on Functional Materials

Functional Behavior of Pseudoelastic NiTi Alloy Under Variable Amplitude Loading

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