Manufacturing issues of thin film NiTi microwrapper

Gill, John; Chang, David T.; Momoda, L.A.; Carman, Greg P.

doi:10.1016/s0924-4247(01)00646-x

Cited by 126 publications

(75 citation statements)

References 22 publications

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“…In contrast with many works which consider bending of bi-layer films consisting of a transforming (active) film on a passive substrate (e.g. see recent paper [1][2][3][4] ) we consider films or plates containing more than two active and passive layers.…”

Section: Introductionmentioning

confidence: 99%

Theory of Multilayer SMA Actuators

Roytburd

Slutsker

2002

Mater. Trans.

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Two types of multilayer actuators based on a shape memory alloy (SMA) film as an active component are explored theoretically. One of them uses the bending of an actuator due to the movement of an austenite/martensite interface of a SMA film parallel to a film plane. Another type of actuation uses the combination of passive layers with different coefficients of thermal expansion for engineering curvature. It is shown that in both cases the actuating deformation of the multilayer actuators can be optimized by the combination of the layers with different elastic properties, misfits and thickness.

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Section: Introductionmentioning

confidence: 99%

Theory of Multilayer SMA Actuators

Roytburd

Slutsker

2002

Mater. Trans.

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“…However, microdevices using functionally graded films [37,38] or bimorph principles [29,43,49,66,79,102] can achieve two-way, out-of-plane displacements with smaller footprints than conventional micromechanisms. Finally, superelastic NiTi thin films are being considered for high-strength surface coatings in MEMS devices, and they have potential for microscale mechanical energy storage devices, and vibration dampeners in microelectronics packaging [39,42].…”

Section: Applicationsmentioning

confidence: 99%

A homogenized free energy model for hysteresis in thin-film shape memory alloys

Massad

Smith

2005

Thin Solid Films

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Thin-film shape memory alloys (SMAs) have become excellent candidates for microactuator fabrication in MEMS due to their capability to achieve very high work densities, produce large deformations, and generate high stresses. In general, the material behavior of SMAs is nonlinear and hysteretic. To achieve the full potential of SMA actuators, it is necessary to develop models that characterize the nonlinearities and hysteresis inherent to the constituent materials. We develop a model that quantifies the nonlinearities and hysteresis inherent to SMAs. The model is based on free energy principles combined with stochastic homogenization techniques. The fully thermomechanical model predicts rate-dependent, polycrystalline SMA behavior, and it accommodates heat transfer issues pertinent to thin-film SMAs. We illustrate aspects of the model through comparison with thin-film SMA superelastic and shape memory effect hysteresis data.

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“…In micro-pumps, a bias force is applied on a SMA membrane by the fluid pressure [9][10][11]. Some micro-actuators used a bilayer (unimorph) structure in which the bias force is applied by an elastic layer attached to the SMA layer [12]. In order to use the full strain capability of the SMA, the SMA layer has to be deformed (detwinned) prior of being connected to the elastic layer.…”

Section: Introductionmentioning

confidence: 99%

A novel shape memory alloy microactuator for large in-plane strokes and forces

Kabla

Ben-David

Shilo

2016

Smart Mater. Struct.

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This paper describes a novel concept for in-plane actuators based on a thin free-standing shape memory alloy (SMA) film. The presented guidelines can be used to design a variety of actuators that can provide a combination of large strokes and forces for linear and rotary motions. A prototype actuator demonstrated a displacement of 45 μm related to 4.5% of the SMA film length, and a force of up to 115 mN related to a stress of 230 MPa in the SMA film without plastic deformations. These capabilities allow the actuator to work against the stiff springs that are essential for the devices' ability to sustain vibrations, impacts, and accelerations.

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Manufacturing issues of thin film NiTi microwrapper

Cited by 126 publications

References 22 publications

Theory of Multilayer SMA Actuators

Theory of Multilayer SMA Actuators

A homogenized free energy model for hysteresis in thin-film shape memory alloys

A novel shape memory alloy microactuator for large in-plane strokes and forces

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