The high potential of shape memory alloys in developing miniature mechanical devices: A review on shape memory alloy mini-actuators

Nespoli, Adelaide; Besseghini, S.; Pittaccio, Simone; Villa, Elena; Viscuso, Stefano

doi:10.1016/j.sna.2009.12.020

Cited by 361 publications

(174 citation statements)

References 22 publications

(29 reference statements)

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“…6. Aside from low frequency response, the other limiting factor in SMA coil actuators is the fact that their activation is only one-way (i.e., the actuator must be deformed, or de-twinned, in the martensite state in order to produce a change in shape during phase transformation) 24,25,27,28 . Their use as actuators is therefore optimized in settings where a restoring or bias force is expected (or can be induced) at the beginning or end of each cycle.…”

mentioning

confidence: 99%

Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

Holschuh

Newman

2014

SPIE Proceedings

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Shape memory alloys (SMA) offer unique shape changing characteristics that can be exploited to produce lowmass, low-bulk, large-stroke actuators. We are investigating the use of low spring index (defined as the ratio of coil diameter to wire diameter) SMA coils for use as actuators in morphing aerospace systems. Specifically, we describe the development and characterization of minimum achievable spring index coiled actuators made from 0.3048 mm (0.012") diameter shape memory alloy (SMA) wire for integration in textile architectures for future compression space suit applications. Production and shape setting of the coiled actuators, as well as experimental test methods, are described. Force, length and voltage relationships for multiple coil actuators are reported and discussed. The actuators exhibit a highly linear (R 2 > 0.99) relationship between isometric blocking force and coil displacement, which is consistent with current SMA coil models; and SMA coil actuators demonstrate the ability to produce significant linear forces (i.e., greater than 8 N per coil) at strains up to 3x their initial (i.e., fully coiled) length. Discussions of both the potential use of these actuators in future compression space suit designs, and the broader viability of these actuators in both macro-and micro-systems, are presented.

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mentioning

confidence: 99%

Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

Holschuh

Newman

2014

SPIE Proceedings

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“…While much previous work has focused on applications of the material for the development of mini-actuators [4], sensory applications of the material also have been suggested in the literature [5]. As a sensory material, a strain-induced martensitic transformation could be detected nondestructively by the associated changes in the electromagnetic properties of the alloy.…”

Section: Electromagnetic Characterization Of Ferromagnetic Shape Memomentioning

confidence: 99%

Electromagnetic characterization of metallic sensory alloy

Wincheski¹,

Simpson²,

Wallace³

et al. 2013

AIP Conference Proceedings

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ABSTRACT. Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

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“…The equations (11) and (12) represent the relationships between stiffness, K, and free length, L 0 , either for a spring or a wire.…”

Section: Case Study: Sma Spring Based Actuatormentioning

confidence: 99%

“…If helical springs or wires are considered, the two fundamental expressions (11) and (12) can be written for the diameter of the wire and for the length of each spring. Following [20] a generic expression of the total length can be obtained, which depends on the dimensionless parameters s 1 , s 2 , s 0 and s F and on the embodiment of the springs.…”

Section: Embodiment Of Sma Antagonist Actuatormentioning

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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The high potential of shape memory alloys in developing miniature mechanical devices: A review on shape memory alloy mini-actuators

Cited by 361 publications

References 22 publications

Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

Electromagnetic characterization of metallic sensory alloy

Optimum Mechanical Design of Binary Actuators Based on Shape Memory Alloys

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