High displacement non-linear asymmetrically designed piezoelectric actuators

Giannopoulos, G.; Monreal, J.; Vantomme, John

doi:10.1117/12.658452

Cited by 3 publications

(3 citation statements)

References 7 publications

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“…[41][42][43] These were followed by actuator studies on bistable piezoelectric composites which used energy techniques to estimate performance. [44][45][46] Both the snap-through and bistable studies showed that small amounts of energy invested in piezoelectric actuators could be used to trigger much more energetic processes if the structure and surrounding materials were designed properly. …”

Section: New Discoveries In Structural Mechanicsmentioning

confidence: 99%

Post-buckled precompressed (PBP) solid state adaptive rotor

Barrett

Barnhart

2010

Active and Passive Smart Structures and Integrated Systems 2010

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This paper is centered on a new actuation philosophy executed on an old rotor design. An adaptive rotor employing twist-active piezoelectric root actuators was used as a testbed to investigate the new branch of structural mechanics devoted to low-and zero-net passive stiffness (ZNPS) structures. One of the more common methods to achieve zero net passive stiffnesses in structures is to employ "negative" springs: that is, mechanisms which when combined with the baseline structure null the passive stiffness of the total structural element. This paper outlines the application of such a system via a Post-Buckled Precompression (PBP) technique at the end of a twist-active piezoelectric rotor blade actuator. The basic performance of the system is handily modeled by using laminated plate theory techniques. A dual cantilevered spring system was used to increasingly null the passive stiffness of the root actuator along the feathering axis of the rotor blade. As the precompression levels were increased, it was shown that corresponding blade pitch levels also increased. The PBP cantilever spring system was designed so as to provide a high level of stabilizing pitch-flap coupling and inherent resistance to rotor propeller moments. Experimental testing showed pitch deflections increasing from just 8° peak-to-peak deflections at 650 V/mm field strength to more than 26° at the same field strength with design precompression levels. Dynamic testing showed the corner frequency of the linear system coming down from 63 Hz (3.8/rev) to 53Hz (3.2/rev). Thrust coefficients manipulation levels were shown to increase from 0.01 to 0.028 with increasing precompression levels. The paper concludes with an overall assessment of the actuator design and conclusions on overall feasibility.

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Section: New Discoveries In Structural Mechanicsmentioning

confidence: 99%

Post-buckled precompressed (PBP) solid state adaptive rotor

Barrett

Barnhart

2010

Active and Passive Smart Structures and Integrated Systems 2010

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“…Although the general case has been examined and the corresponding formulation has been established, the existence of continuous piezoelectric layers that provide actuation in the whole length of the beam corresponds to more realistic applications. However, in the work of Giannopoulos et al [12] it has been shown that asymmetric bimorph actuators can be used with impressive results. The formulation presented in the previous section is simplified in order to describe the continuous actuation problem.…”

Section: Continuous Piezoelectric Actuatorsmentioning

confidence: 99%

Snap-through buckling behavior of piezoelectric bimorph beams: I. Analytical and numerical modeling

Giannopoulos¹,

Monreal²,

Vantomme³

2007

Smart Mater. Struct.

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Piezoelectric structures are used in a variety of applications where instant response, high energy conversion efficiency and accurate control are required. However, it is widely known that piezoelectric structures suffer from a series of drawbacks, among which the most important is the small displacement capacity. A number of techniques have been used in order to transform the micron-scale displacements of PZT layers into meaningful millimeter-scale ones. Non-linear mechanics belong to this category, providing the possibility to transform a traditional bimorph linear output structure into a non-linear high displacement actuator with increased combination of force/displacement output. In the present work the analytical modeling and the subsequent analysis of non-linear actuators with enhanced characteristics in terms of displacement is presented. The piezoelectric structure that is studied is a traditional bimorph structure with two piezoelectric layers and an aluminum substrate. The main concept is to leverage non-linear mechanics, and more specifically snap-through buckling, so that large displacements can be achieved with the transition of the structure from one equilibrium position to another. During the development process the importance of boundary conditions has been revealed and thus special attention has been provided to this issue. A modified analytical model was elaborated in order to come up with a closed form solution including relaxed boundary conditions. The experimental verification of the analytical and numerical model is presented in part II.

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“…Several related studies were conducted on structures which exhibited negative stiffnesses through buckling effects associated with snap-through events [40][41][42]. These were followed by actuator studies on bistable piezoelectric composites which used energy techniques to estimate performance [43][44][45]. Both the snap-through and bistable studies showed that small amounts of energy invested in piezoelectric actuators could be used to trigger much more energetic processes if the structure and surrounding materials were designed properly.…”

Section: New Discoveries In Structural Mechanicsmentioning

confidence: 99%

Solid State Adaptive Rotor Using Postbuckled Precompressed, Bending-Twist Coupled Piezoelectric Actuator Elements

Barrett

Barnhart

2012

Smart Materials Research

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This paper is centered on a new actuation mechanism which is integrated on a solid state rotor. This paper outlines the application of such a system via a Post-Buckled Precompression (PBP) technique at the end of a twist-active piezoelectric rotor blade actuator. The basic performance of the system is handily modeled by using laminated plate theory techniques. A dual cantilevered spring system was used to increasingly null the passive stiffness of the root actuator along the feathering axis of the rotor blade. As the precompression levels were increased, it was shown that corresponding blade pitch levels also increased. The PBP cantilever spring system was designed so as to provide a high level of stabilizing pitch-flap coupling and inherent resistance to rotor propeller moments. Experimental testing showed pitch deflections increasing from just 8 • peak-to-peak deflections at 650 V/mm field strength to more than 26 • at the same field strength with design precompression levels. Dynamic testing showed the corner frequency of the linear system coming down from 63 Hz (3.8/rev) to 53 Hz (3.2/rev). Thrust coefficients manipulation levels were shown to increase from 0.01 to 0.028 with increasing precompression levels. The paper concludes with an overall assessment of the actuator design.

show abstract

High displacement non-linear asymmetrically designed piezoelectric actuators

Cited by 3 publications

References 7 publications

Post-buckled precompressed (PBP) solid state adaptive rotor

Post-buckled precompressed (PBP) solid state adaptive rotor

Snap-through buckling behavior of piezoelectric bimorph beams: I. Analytical and numerical modeling

Solid State Adaptive Rotor Using Postbuckled Precompressed, Bending-Twist Coupled Piezoelectric Actuator Elements

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