Tuning the mechanical behaviour of structural elements by electric fields

Lillo, Luigi Di; Raither, Wolfram; Bergamini, Andrea; Zündel, Manuel; Ermanni, Paolo

doi:10.1063/1.4809728

Cited by 25 publications

(31 citation statements)

References 17 publications

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“…Previously, EBL has been used for vibration suppression [6], with limited investigation into the use of variable stiffness as a function in its own right [2].…”

Section: Existing Literaturementioning

confidence: 99%

“…The intention is to assess the achievable change in bending stiffness resulting from the application of electrostatic adhesion at the mid-plane in a variety of beams. Existing research in this field has, to the best of the authors' knowledge, only considered the use of electrostatic adhesion in this manner for thin plate structures in bending [2], and only for relatively low forces in sandwich structures [3]. This research aims to consider sandwich structures at higher levels of force to extend the use of such technology to a wider range of applications.…”

Section: Introductionmentioning

confidence: 99%

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Electrostatic adhesion for added functionality of composite structures

Heath

Bond

Potter

2016

Smart Mater. Struct.

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Electrostatic adhesion can be used as a means of reversible attachment. The incorporation of electrostatic adhesion into fibre reinforced polymer (FRP) composite structures could provide significant value added functionality. Imparting large potential differences (~ 2 kV) across electrodes generates an attractive force, thus providing a means of attachment. This could be used as a reversible latching mechanism or as a means of controllable internal connectivity. Varying the connectivity for discrete elements of a substructure of a given design allows for control of internal load paths and moment of area of the cross section. This could facilitate variable stiffness (both in bending and torsion). Using a combination of existing fabrication techniques, functional electrodes have been integrated within a FRP. Copper polyimide thin film laminate material has been both co-cured with carbon fibre reinforced epoxy (CFRP) and bonded to PVC closed cell foam core material to provide a range of structural configurations with integrated electrodes. The ability of such integrated devices to confer variations in global bending stiffness of basic beam structures is investigated. Through the application of 4 kV across integrated electrostatic adhesive devices, a 112% increase in flexural stiffness has been demonstrated for a composite sandwich structure.

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“…Previously, EBL has been used for vibration suppression [6], with limited investigation into the use of variable stiffness as a function in its own right [2].…”

Section: Existing Literaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrostatic adhesion for added functionality of composite structures

Heath

Bond

Potter

2016

Smart Mater. Struct.

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“…The aforementioned tests used thin polyimide copper devices that would have a far increased conformability than the PU mounted devices considered herein, as demonstrated by the low load to deflection behaviour demonstrated in the three-point flexural tests in (Di Lillo et al, 2013). Even at low voltages, flexible EBL devices would allow for a greater degree of 'pull-in' due to the electrostatic force of attraction between the electrodes, potentially further reducing the air gap thickness.…”

Section: Resultsmentioning

confidence: 99%

“…This concept was extended, replacing the permanent adhesive between adjacent layers in a composite beam structure with reversible electrostatic bonding (Bergamini, 2009;Bergamini et al, 2006Bergamini et al, , 2007. The potential applications for EBL devices are numerous, including morphing structure applications (Previtali et al, 2015;Raither et al, 2012Raither et al, , 2013Raither et al, , 2014, vibration suppression (Bergamini et al, 2006(Bergamini et al, , 2007, or variable stiffness functionality (Di Lillo et al, 2013;Heath et al, 2016a). Significant progress has been made in increasing the level of electrostatic holding force generated, with greater understanding of thin film dielectrics used for EBL devices (Di Lillo et al, 2011) and improved close contact between structurally integrated electrodes through fabrication process enhancements (Heath et al, 2016a).…”

Section: Figure 1: Example Of An Ebl Configurationmentioning

confidence: 99%

“…Strong electric fields generated from closely spaced electrode elements can generate significant electrostatic forces of attraction which can be utilised to control the structural coupling of laminated elements (Bergamini et al, 2006;Di Lillo et al, 2013;Heath et al, 2016a;Raither et al, 2014;Tabata et al, 2001). Figure 1 is an example of an EBL device, showing conductive elements attached to a host structure and separated by a thin dielectric layer.…”

Section: Introductionmentioning

confidence: 99%

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Interlocking electro-bonded laminates

Heath¹,

Bond

Potter

2016

Journal of Intelligent Material Systems and Structures

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Laminates (EBL) are structures that utilise the electrostatic force of attraction, generated between closely spaced electrode elements when subject to high potential difference (~2 kV), to control internal structural coupling.Control of internal connectivity allows for flexural stiffness modulation, with significant potential applications including vibration suppression and morphing applications. Existing EBL devices use parallel planar electrode elements. For this study Polyurethane (PU) core structures were cast with interlocking geometries based on a simple cosine wave form. By introducing this additional complexity to the electrodes, additional electrodeelectrode contact area is available within a set external geometric profile, whilst also introducing directional resistance to sliding motion between the two surfaces. Interlocking Electro-Bonded Laminate (iEBL) devices are demonstrated with electrostatic holding force capabilities similar to equivalent planar devices, with the added benefit of alignment and sliding restrictions provided by the directional elements. A novel enhancement to the existing EBL technology has thus been demonstrated.

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Materials with Electroprogrammable Stiffness

Levine

Turner

2021

Advanced Materials

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Stiffness is a mechanical property of vital importance to any material system and is typically considered a static quantity. Recent work, however, has shown that novel materials with programmable stiffness can enhance the performance and simplify the design of engineered systems, such as morphing wings, robotic grippers, and wearable exoskeletons. For many of these applications, the ability to program stiffness with electrical activation is advantageous because of the natural compatibility with electrical sensing, control, and power networks ubiquitous in autonomous machines and robots. The numerous applications for materials with electrically driven stiffness modulation has driven a rapid increase in the number of publications in this field. Here, a comprehensive review of the available materials that realize electroprogrammable stiffness is provided, showing that all current approaches can be categorized as using electrostatics or electrically activated phase changes, and summarizing the advantages, limitations, and applications of these materials. Finally, a perspective identifies state‐of‐the‐art trends and an outlook of future opportunities for the development and use of materials with electroprogrammable stiffness.

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Tuning the mechanical behaviour of structural elements by electric fields

Cited by 25 publications

References 17 publications

Electrostatic adhesion for added functionality of composite structures

Electrostatic adhesion for added functionality of composite structures

Interlocking electro-bonded laminates

Materials with Electroprogrammable Stiffness

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