Internal loops in superelastic shape memory alloy wires under torsion – Experiments and simulations/predictions

Rao, Ashwin; Ruimi, Annie; Srinivasa, Arun R.

doi:10.1016/j.ijsolstr.2014.09.002

Cited by 31 publications

(20 citation statements)

References 61 publications

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“…4.5a) during the phase transformation event can be clearly observed in torque-time response as shown in Fig. 4.5b [4]. A much more complex situation is shown in Fig.…”

Section: Sma Wire Response-torsional Loadingmentioning

confidence: 82%

“…In applications, understanding SMA component responses under partial or fully transformed cases with internal loops is of particular importance as the entire response might not be utilized always and only a portion of the entire response (internal loop) might be of significance to designers [3,4]. The area of these smaller hysteretic internal loops depends on the extent of the loading and unloading levels that the component is subjected to during service within the transformation region (plateau region) [4]. A few examples will be discussed in the following sections to highlight these features and illustrate them better.…”

Section: Sma Wire Response-tensile Loadingmentioning

confidence: 99%

“…A much more complex situation is shown in Fig. 4.6 where complex loading-unloading scenarios can be observed that result more complex internal loops of smaller hysteretic responses [4].…”

Section: Sma Wire Response-torsional Loadingmentioning

confidence: 99%

See 2 more Smart Citations

Basic SMA Component Geometries and Responses

Rao

Srinivasa

Reddy

2015

Design of Shape Memory Alloy (SMA) Actuators

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SMA components must allow for a large surface area compared to their volume in order for them to be able to be cooled rapidly and repeated use at reasonable actuation frequencies. Thus SMAs are commonly used in the form of wires/rods, springs, tubes or beams under different loading conditions (tension, torsion or bending) for exploiting their unique characteristics in many practical applications. All these geometries are governed by their high surface to volume ratios. To begin with, a review of different SMA geometries commonly used in different applications and their complex responses are discussed below.

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“…4.5a) during the phase transformation event can be clearly observed in torque-time response as shown in Fig. 4.5b [4]. A much more complex situation is shown in Fig.…”

Section: Sma Wire Response-torsional Loadingmentioning

confidence: 82%

Section: Sma Wire Response-tensile Loadingmentioning

confidence: 99%

See 1 more Smart Citation

Basic SMA Component Geometries and Responses

Rao

Srinivasa

Reddy

2015

Design of Shape Memory Alloy (SMA) Actuators

Self Cite

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“…Research published by Likhachev (1995), Dutta and Ghorbel (2005), and Feng et al (2011) fall in this category. Adopting the Preisach hysteresis model, Rao et al (2014) developed a thermodynamically consistent model able to predict formation of internal branches, while Kilicarslan et al (2014) scheduled and tested a linear-parameter varying controller in real-time for SMA actuators operating under a range of hysteresis conditions. Prediction of incomplete transformation branches from a phenomenological point-of-view has been considered in the one-dimensional (1-D) model of Bekker and Brinson (1998) that was based on the study of material’s response on the σ − T plane (phase diagram of SMAs).…”

Section: Adopted Constitutive Equationsmentioning

confidence: 99%

Effect of shape memory alloys partial transformation on the response of morphing structures encompassing shape memory alloy wire actuators

Karakalas

Machairas

Saravanos

2019

Journal of Intelligent Material Systems and Structures

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The present article investigates and explores the effect of partial phase transformation on the response of shape adaptive/morphing structures controlled by shape memory alloy wire actuators subject to variable trajectory and high actuation speed requirements, where the effect of partial transformation becomes more dominant. A modified constitutive model is adopted for the prediction of the thermo-mechanically coupled response on a trailing edge shape adaptive rib prototype intended for active load alleviation in large wind turbine blades, and the simulated behavior is subsequently correlated with experimental results. The experimentally validated model is further used to predict the response of the full-scale camber-line adaptive structure with shape memory alloy Ni51Ti49 wt% actuators in antagonistic configurations, under demanding operational time target trajectories at extreme turbulence conditions. Comparison of the results, with a case that omits partial transformation behavior, reveals substantial improvements in the predicted target trajectories, actuation speed, actuator stresses, and required operational temperature variation. The latter discloses the enhanced potential of shape memory alloy actuators to provide higher transformation rate and possibly higher fatigue life combined with lower energy demands toward the design and realization of efficient morphing structures.

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“…The microscopic models treat phenomena on a molecular level, therefore the macroscopic phenomenological models are more attractive from practical point of view. In the literature one can find a lot of interesting and thorough description of SMAs [4][5][6][7][8][9][10] and their applications [11][12][13][14]. Different models of SMA give various results depending on nonlinear phenomenon which are taken into account.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of SMA micro-actuator in biomechanical system

et al. 2018

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Abstract. In this paper the polynomial model of shape memory alloy is used to characterise properties of a micro-actuator which is applied as a new middle ear prosthesis. A two degrees of freedom model of the reconstructed middle ear is solve by means of multiple time scales method. The system has various behaviours near the primary resonance depending on ambient temperature. The special case when relative temperature θ = 1.0 characterises untypical resonance curve. Increasing temperature to the normal human body one the resonance curves are typical. Then the system has only one periodic solution if the excitation is not too strong.

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Internal loops in superelastic shape memory alloy wires under torsion – Experiments and simulations/predictions

Cited by 31 publications

References 61 publications

Basic SMA Component Geometries and Responses

Basic SMA Component Geometries and Responses

Effect of shape memory alloys partial transformation on the response of morphing structures encompassing shape memory alloy wire actuators

Dynamics of SMA micro-actuator in biomechanical system

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