Effect of bending on the performance of spool-packaged shape memory alloy actuators

Redmond, John A.; Brei, Diann; Luntz, Jonathan; Browne, Alan L.; Johnson, Nancy L.

doi:10.1117/12.816666

Cited by 2 publications

(1 citation statement)

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“…All wires were 'trained' through a thermo-mechanical cyclic process by the manufacturer prior to subsequent surface treatment. See [32][33][34][35] for representative applications and for more details on the thermo-mechanical behavior of Flexinol R wires. Typically these wires exhibit a dark surface due to their natural oxide layer which is (approximately) 400 nm thick [36].…”

Section: Surface Treatmentsmentioning

confidence: 99%

Adhesion of nickel–titanium shape memory alloy wires to thermoplastic materials: theory and experiments

Antico¹,

Zavattieri²,

Hector³

et al. 2012

Smart Mater. Struct.

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We present a combined experimental/theoretical study aimed at enhancing adhesion between a NiTi wire and a thermoplastic polyolefin (TPO) matrix in which it is embedded. NiTi wire surfaces were subjected to the following surface treatments prior to pull-out tests: (i) treatment with an acid etch or chemical conversion coating and (ii) application of a surface microgeometry to enhance mechanical interlocking between the wire and the TPO matrix. Nanometer to micron-scale NiTi wire surface features were examined with atomic force microscopy. The extent to which each treatment increased the pull-out force was quantified. Existing theoretical models of wire pull-out based upon strength of materials and linear elastic fracture mechanics are reviewed. Results from a finite element model (FEM), wherein the NiTi/TPO matrix interface is modeled with a cohesive zone model, suggest that the interface behavior strongly depends on the cohesive energy. The FEM model properly accounts for energy dissipation at the debonding front and inelastic deformation in a NiTi wire during pull-out. We demonstrate that residual stresses from the molding process significantly influence mode mixity at the debonding front.

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Section: Surface Treatmentsmentioning

confidence: 99%

Adhesion of nickel–titanium shape memory alloy wires to thermoplastic materials: theory and experiments

Antico¹,

Zavattieri²,

Hector³

et al. 2012

Smart Mater. Struct.

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The Design and Experimental Validation of an Ultrafast Shape Memory Alloy ResetTable (SMART) Latch

Redmond

Brei

Luntz

et al. 2010

Journal of Mechanical Design

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Latches are essential machine elements utilized by all sectors (military, automotive, consumer, manufacturing, etc.) with a growing need for active capabilities such as automatic release and reset, which require actuation. Shape memory alloy (SMA) actuation is an attractive alternative technology to conventional actuation (electrical, hydraulic, etc.) because SMA, particularly in the wire form, is simple, inexpensive, lightweight, and compact. This paper introduces a fundamental latch technology, referred to as the T-latch, which is driven by an ultrafast SMA wire actuator that employs a novel spool-packaged architecture to produce the necessary rotary release motion within a compact footprint. The T-latch technology can engage passively, maintain a strong structural connection in multiple degrees of freedom with zero power consumption, actively release within a very short timeframe (<20 ms, utilizing the SMA spooled actuator), and then repeat operation with automatic reset. The generic architecture of the T-latch and governing operational behavioral models discussed within this paper provide the background for synthesizing basic active latches across a broad range of applications. To illustrate the utility and general operation of the T-latch, a proof-of-concept prototype was designed, built, and experimentally characterized regarding the basic functions of engagement, retention, release, and reset for a common case study of automotive panel lockdown. Based on the successful demonstration and model validation presented in this study, the T-latch demonstrates its promise as an attractive alternative technology to conventional technologies with the potential to enable simple, low-cost, lightweight, and compact active latches across a broad range of industrial applications.

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Effect of bending on the performance of spool-packaged shape memory alloy actuators

Cited by 2 publications

References 0 publications

Adhesion of nickel–titanium shape memory alloy wires to thermoplastic materials: theory and experiments

Adhesion of nickel–titanium shape memory alloy wires to thermoplastic materials: theory and experiments

The Design and Experimental Validation of an Ultrafast Shape Memory Alloy ResetTable (SMART) Latch

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