Thermomechanical fatigue of shape memory alloys

Lagoudas, Dimitris C.; Miller, David A.; Rong, Lijian; Kumar, Pradeep

doi:10.1088/0964-1726/18/8/085021

Cited by 115 publications

(82 citation statements)

References 31 publications

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“…The stroke is primarily limited by the maximum strain that the alloy can withstand for the expected life as shown in [24], [25]. The backup element needed to recover the stroke prevents the SMA element from recovering completely its shape is a further cause of stroke loss.…”

Section: Design Of Compensated Sma Actuatorsmentioning

confidence: 99%

“…In the practical use of shape memory alloys for making actuators, the materials remain within the linear elastic range at the higher temperature but are strained beyond the elastic limit when cooled to the lower temperature. The maximum strain, ε adm is small enough to ensure the desired fatigue life [24][25] but large enough to maximize the stroke of the actuator for a given amount of material involved. Since this analysis is aimed at dimensioning the binary actuator for the extreme positions, irrespective of the intermediate state, the behaviour of the material is approximated by segments OA' (martensite) and OC (austenite) in Figure 1a.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Optimum Mechanical Design of Binary Actuators Based on Shape Memory Alloys

Spaggiari¹,

Mammano²,

Dragoni³

2012

Smart Actuation and Sensing Systems - Recent Advances and Future Challenges

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Many SMAs applications have been studied in recent years. Kuribayashi [5] proposes a rotary joint based on a bending SMA actuator, while, in [6] design and applications of SMA Smart Actuation and Sensing Systems -Recent Advances and Future Challenges 4 actuators are presented. Microrobots can be developed using SMA as shown in [7] where there is a basic method to design the SMA spring based on a thermo-electromechanical approach. Reynaerts et al. [8] present design considerations concerning the choice of the active element to evaluate SMA actuator efficiency. Lu et al. [9] design a high strain shape memory actuator taking into account pseudoplasticity and compared its performance with traditional actuators. Due to SMA high non linearity, design curves relying on experiments are proposed in [10] to assess the SMA actuator geometry. A comprehensive review of applications of SMAs in the field of mechanical actuation has recently been published in [11]. Jansen et al [12] develop a linear actuator used as a drive module in an angular positioning mini-actuator. This architecture allows both large force and long strokes to be obtained. Strittmatter et al. [13] propose a SMA actuator for the activation of a hydraulic valve, biased by a conventional spring. Bellini et al. [14] propose a linear SMA actuator able to vary the air inflow for internal combustion engines, improving gas combustion and leading to higher efficiency. Haga et al. [15] propos a mini-actuator to be used in Braille displays. Elwaleed et al.[16] develop a SMA beam actuator able to amplify the SMA actuator strain using elastically instable beams. Among the proposed actuator there is lack of simple design instruments to provide basic information to the designer, either due to specific constraints of application or due to the high complexity of the thermomechanical material models used. In order to answer for an analytical design methodology, the author described in several technical publications a set of equations useful for linear [18] and rotary application [19]. The authors developed the design equations both for SMA actuators under a general system of external forces [20] and produced the design formulae to increase the output stroke thanks to negative stiffness compensators [21]. Moreover two peculiar systems were designed and developed: a telescopic actuator [22] and a wire on drum system [23]. The present work reviews and improves the design rules developed by the authors and set them in a coherent formal analytical framework. Design examples are provided to illustrate the step-by-step application of the design optimization procedures for realistic case studies. Challenges and issues in SMA actuators designThe three main challenges in SMA actuator design are: obtaining a simple and reliable material model, increasing the stroke of the actuator and finding design equations to guide the engineer in dimensioning the actuator. To design SMA actuators, a material model must describe the mechanical behaviour of the alloy in two temperature ranges: b...

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Section: Design Of Compensated Sma Actuatorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimum Mechanical Design of Binary Actuators Based on Shape Memory Alloys

Spaggiari¹,

Mammano²,

Dragoni³

2012

Smart Actuation and Sensing Systems - Recent Advances and Future Challenges

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show abstract

“…Manson Coffin-like relationship has been proposed by Lagoudas et al (2009b) to determine the irrecoverable strain accumulation of NiTiCu SMAs as a function of the number of cycles to failure for different stress levels, for both partial and complete transformations.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional constitutive model for structural and functional fatigue of shape memory alloy actuators

Chemisky

Hartl

Meraghni

2018

International Journal of Fatigue

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractA three-dimensional constitutive model is developed that describes the behavior of shape memory alloy actuators undergoing a large number of cycles leading to the development of internal damage and eventual catastrophic failure. Physical mechanisms such as transformation strain generation and recovery, transformation-induced plasticity, and fatigue damage associated with martensitic phase transformation occurring during cyclic loading are all considered within a thermodynamically consistent framework. Fatigue damage in particular is described utilizing a continuum theory of damage. The total damage growth rate has been formulated as a function of the current stress state and the rate of martensitic transformation such that the magnitude of recoverable transformation strain and the complete or partial nature of the transformation cycles impact the total cyclic life as per experimental observations. Simulation results from the model developed are compared to uniaxial actuation fatigue tests at different applied stress levels. It is shown that both lifetime and the evolution of irrecoverable strain are accurately predicted by the developed model.

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“…The rational design of SMA actuators requires reliable data on the thermomechanical fatigue behavior, both structural and functional, of these materials. Most of the information stored in the technical literature involves the mechanical fatigue of SMAs in the superelastic state (Ref 1) while much less data are available on the thermomechanical fatigue of these alloys (Ref [1][2][3][4][5][6][7] and this field is still open for physical insight and engineering work.…”

Section: Introductionmentioning

confidence: 99%

Effect of Stress, Heating Rate, and Degree of Transformation on the Functional Fatigue of Ni-Ti Shape Memory Wires

Mammano

Dragoni

2015

J. of Materi Eng and Perform

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Shape memory alloys, particularly in the form of thin wires, are becoming increasingly attractive in the industrial field for the construction of compact actuators with high-power density. The structural and functional fatigue behavior of shape memory alloys undergoing thermomechanical cycling has been investigated only partially in the technical literature. In particular, the effects of operating parameters like the degree of martensite-austenite transformation and the heating rate on the fatigue life of the alloy have received very little attention so far. This paper explores the effect of these two parameters on the fatigue response of commercial SMA wires exposed to two linear stress-strain profiles during cycling. The results show the beneficial effects of partial transformation on the structural and functional life of the wires, with negligible loss of performance in terms of useful stroke. Though less markedly, the heating rate also has an effect on the structural and functional response, with the sine waveform supply performing better than the square profile

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Thermomechanical fatigue of shape memory alloys

Cited by 115 publications

References 31 publications

Optimum Mechanical Design of Binary Actuators Based on Shape Memory Alloys

Optimum Mechanical Design of Binary Actuators Based on Shape Memory Alloys

Three-dimensional constitutive model for structural and functional fatigue of shape memory alloy actuators

Effect of Stress, Heating Rate, and Degree of Transformation on the Functional Fatigue of Ni-Ti Shape Memory Wires

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