Design, characterization and perspectives of shape memory alloy elements in miniature sensor proof of concept

Nespoli, Adelaide; Rigamonti, Daniela; Villa, Elena; Passaretti, Francesca

doi:10.1016/j.sna.2014.08.001

Cited by 19 publications

(14 citation statements)

References 28 publications

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“…In particular, it can be observed that the amount of plastic deformation sustained by the austenite phase differs from that sustained by the martensite one: approximately 10 mm for the austenite and approximately 2.5 mm for the martensite. This discrepancy is likely due to the defects induced by the thermo-mechanical cycling that hindered the complete recovery of the austenitic phase at high temperatures and drove the two-way shape memory effect [10] in the martensite, reducing the measured plastic deformation at lower temperatures. Furthermore, the thermal hysteresis decreased with the increase in the number of cycles (see also Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The deformation of the martensite phase is usually achieved by the application of an external load able to promote the re-orientation of martensite variants (de-twinning); during detwinning, the high mobility of the martensite variant interfaces minimises the strain energy and allows for high deformation. The shape recovery obtained after heating de-twinned martensite is normally used to promote mechanical work, and it finds several interesting applications in the field of actuation [3][4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Functional properties and morphology of NiTi articulated actuation elements during thermo-mechanical cyclic tests

2015

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Shape memory alloys (SMAs) are active materials able to recover large strains over several thermo-mechanical cycles. In the actuation field, this strain recovery is principally exploited on the mini and micro scales at which SMAs exhibit their highest power density with respect to common lightweight technologies. During the repetitive actuation of a SMA element, certain events occur: strain drift at the beginning of cyclic testing, the accumulation of plastic deformation, and strain stabilisation. In this study, these events as well as the overall mechanical response of an articulated NiTi element were monitored through calorimetry and scanning electron microscopy. Fatigue and cyclic stability were tested under different loads and under different aging conditions. In addition, the surface morphology was continuously observed via scanning electron microscopy to monitor crack growth and propagation during the fatigue test. Finally, before and after the fatigue test, samples were tested through calorimetry to investigate the overall microstructural homogeneity. Results confirm the high potential of the proposed geometry for the development of NiTi non-conventional active elements in the miniature actuation field.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Functional properties and morphology of NiTi articulated actuation elements during thermo-mechanical cyclic tests

2015

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“…In particular, the shape recovery is typically exploited in the actuator field, where the material performs against an external load inducing mechanical work [18,19,20]. At the base of these mechanical attitudes, there is a thermoelastic martensitic transformation between two solid phases, austenite (BCC lattice) and martensite (monoclinic lattice), that are stable in two critical temperature ranges.…”

Section: Actuating Shape Memory Alloys At High Frequencymentioning

confidence: 99%

Design and experimental characterization of a NiTi-based, high-frequency, centripetal peristaltic actuator

Borlandelli

Nespoli²,

Rigamonti³

et al. 2015

Smart Mater. Struct.

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Abstract. Development and experimental testing of a device for peristaltic pumping We present and discuss the results of the full experimental investigation of the actuator performance, measured in terms of its ability to reduce the pipe diameter, at a sustained frequency of 1.5 Hz. Moreover, we investigate how the diameter contraction is influenced ✿✿✿✿✿✿ affected ✿ by various design parameters as well as actuation frequencies up to 4 Hz. We manage to make the NiTi wire work at 3% in strain, cyclically providing the designed pipe wall displacement. The actuator performance is found to decay approximately linearly with actuation frequencies up to 4 Hz. Also, the interface between the wire and the aluminum parts is found to be essential in defining the actuator functional performance

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“…The advantage to produce near net components through additive manufacturing technologies allows to overcome several issues that make the conventional methods ineffective in the production of high‐quality complex NiTi components. [ 22–28 ] Among the known additive manufacturing processes, selective laser melting (SLM) uses a laser‐beam source to selectively melt micrometric metal powders, layer upon layer, to fabricate 3D objects. [ 29 ] Recently, SLM has become very attractive for the fabrication of NiTi components [ 30–34 ] and significant efforts have been mainly focused on the selection of the process parameters that maximize the thermo‐mechanical performance.…”

Section: Introductionmentioning

confidence: 99%

A Study on Damping Property of NiTi Elements Produced by Selective Laser‐Beam Melting

et al. 2021

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The damping properties of NiTi elements produced through selective laser melting are investigated by tuning the process parameters. To this end, twelve parameters’ sets are selected to fabricate fully‐dense NiTi specimens. Damping is evaluated through loss factor index, mechanical loading cycles (up to 104 cycles), solicitation frequency and strain amplitude. Results confirm that NiTi fabricated through selective laser‐beam melting is an excellent candidate to substitute conventional materials when used in the martensite phase. Furthermore, the selected process parameters enable specific damping performances that can be collected in damping maps which turn out to be practical tools for the fabrication of NiTi parts with tunable damping response.

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Design, characterization and perspectives of shape memory alloy elements in miniature sensor proof of concept

Cited by 19 publications

References 28 publications

Functional properties and morphology of NiTi articulated actuation elements during thermo-mechanical cyclic tests

Functional properties and morphology of NiTi articulated actuation elements during thermo-mechanical cyclic tests

Design and experimental characterization of a NiTi-based, high-frequency, centripetal peristaltic actuator

A Study on Damping Property of NiTi Elements Produced by Selective Laser‐Beam Melting

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