Meso scale flextensional piezoelectric actuators

York, Peter A.; Jafferis, Noah T.; Wood, Robert J.

doi:10.1088/1361-665x/aa9366

Cited by 17 publications

(16 citation statements)

References 26 publications

(34 reference statements)

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“…Designing metallic structures capable of large thermal expansion involves engineering mesoscale architectures that can leverage the small thermal strains typical of metals (∼ 10 −6 / • C) to produce large global displacements. In other contexts, e.g., to amplify piezoelectric strains [40][41][42][43][44][45][46], to harvest energy [47,48] or attenuate vibrations [49][50][51], a similar goal has been achieved using displacement amplification mechanisms. Typically, these mechanisms comprise a combination of rigid links and compliant hinges designed to leverage geometric constraining.…”

Section: Introductionmentioning

confidence: 99%

Temperature-induced shape morphing of bi-metallic structures

Taniker

Celli

Pasini

et al. 2020

International Journal of Solids and Structures

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In this work, we study the thermo-mechanical behavior of metallic structures designed to significantly change shape in response to thermal stimuli. This behavior is achieved by arranging two metals with different coefficient of thermal expansion (CTE), Aluminum and Titanium, as to create displacement-amplifying units that can expand uniaxially. In particular, our design comprises a low-CTE bar surrounded by a high-CTE frame that features flexure hinges and thicker links. When the temperature increases, the longitudinal expansion of the high-CTE portion is geometrically constrained by the low-CTE bar, resulting in a large tangential displacement. Our design is guided by theoretical models and numerical simulations. We validate our approach by fabricating and characterizing individual units, one dimensional arrays and three-dimensional structures. Our work shows that structurally robust metallic structures can be designed for large shape changes. The results also demonstrate how harsh environmental conditions (e.g., the extreme temperature swings that are characteristic of extraterrestrial environments) can be leveraged to produce function in a fully passive way.

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Section: Introductionmentioning

confidence: 99%

Temperature-induced shape morphing of bi-metallic structures

Taniker

Celli

Pasini

et al. 2020

International Journal of Solids and Structures

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“…A microgripper implementation has recently been reported by York et al, achieving a 106 µm free displacement and 73 mN of blocked force, from an 8 mm long piezoelectric beam [3] and 300 V. A photograph of this microgripper illustrating clearly the bridge-and-lever structure combination is shown in Fig. 13.…”

Section: Flextensional Mechanismsmentioning

confidence: 97%

“…Both methods can result in motion output in the tens of nanometers per volt range. For example, the PZT beam of [3] achieves displacement of several micrometers at 300 V, while the Multi Layer Actuators of Cedrat Technologies provide displacements up to 20 µm [4]. The ultimate limiting factor of practically achievable stroke by an active material layer is its tensile strength or dielectric breakdown limit.…”

Section: Actuation Mechanismsmentioning

confidence: 99%

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Micro Motion Amplification–A Review

et al. 2020

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Many motion-active materials have recently emerged, with new methods of integration into actuator components and systems-on-chip. Along with established microprocessors, interconnectivity capabilities and emerging powering methods, they offer a unique opportunity for the development of interactive millimeter and micrometer scale systems with combined sensing and actuating capabilities. The amplification of nanoscale material motion to a functional range is a key requirement for motion interaction and practical applications, including medical micro-robotics, micro-vehicles and micro-motion energy harvesting. Motion amplification concepts include various types of leverage, flextensional mechanisms, unimorphs, micro-walking / micro-motor systems, and structural resonance. A review of the research stateof-art and product availability shows that the available mechanisms offer a motion gain in the range of 10. The limiting factor is the aspect ratio of the moving structure that is achievable in the microscale. Flexures offer high gains because they allow the application of input displacement in the close vicinity of an effective pivotal point. They also involve simple and monolithic fabrication methods allowing combination of multiple amplification stages. Currently, commercially available motion amplifiers can provide strokes as high as 2% of their size. The combination of high-force piezoelectric stacks or unimorph beams with compliant structure optimization methods is expected to make available a new class of high-performance motion translators for microsystems.

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“…In both cases, the size of the final components was a few centimeters, but neither work characterized the dynamic behavior of the compliant element. York et al [24] designed an actuator 8 mm in length, with a travel range of a few hundredths of a millimeter. A transient response analysis was also conducted, in preparation for high speed actuation applications.…”

Section: Literature Reviewmentioning

confidence: 99%

Modal Analysis of a New Thermosensitive Actuator Design for Circuit Breakers Based on Mesoscale U-Shaped Compliant Mechanisms

Ahuett–Garza

Melecio

Orta

2018

Mathematical Problems in Engineering

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A new mesoscale thermosensitive actuator design for circuit breakers based on a U-shaped compliant mechanism was introduced as a potential replacement for bimetal strips in miniature circuit breakers. In a previous study, the response of this design to the thermal fields produced by a steady current flow was analyzed. This article presents a modal analysis of the compliant mechanism. The goal of the analysis is to compare the natural frequencies of the mechanism with the frequency of the magnetic loads caused by the flow of the alternating currents. Simulations with simple beam elements and 3D elements are presented and results are compared with experimental measurements. The study finds that the natural frequency of the mechanism differs by a factor of about 8 with the AC frequency. The conclusion is that the proposed compliant mechanism design’s performance as a thermal actuator will not be affected by the cyclic loads generated by the forces induced by the AC magnetic fields.

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Meso scale flextensional piezoelectric actuators

Cited by 17 publications

References 26 publications

Temperature-induced shape morphing of bi-metallic structures

Temperature-induced shape morphing of bi-metallic structures

Micro Motion Amplification–A Review

Modal Analysis of a New Thermosensitive Actuator Design for Circuit Breakers Based on Mesoscale U-Shaped Compliant Mechanisms

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