Analysis of multilayer electro-active tubes under different constraints

Bortot, Eliana

doi:10.1177/1045389x18803449

Cited by 8 publications

(7 citation statements)

References 46 publications

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“…Other standard instabilities in the multilayered soft dielectrics, including loss of strong ellipticity, bifurcation, and electric breakdown, were also examined [36,37]. The recent work of [38] considered the nonlinear response of a multilayer electro-active tube and investigated in detail the effects of geometrical properties and constraint conditions on the deformation. Also, [39] studied the intelligent bending deformation and the associated bifurcation instability.…”

Section: Introductionmentioning

confidence: 99%

Axisymmetric vibration and stability of dielectric-elastic tubular bilayer system

Almamo,

Su,

Chen

et al. 2024

Proc. R. Soc. A.

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Modern transducers and actuators may have functional layers with multi-field coupling and some elastic layers. This paper considers a tubular bilayer system consisting of a thin dielectric tube coated with a thick elastic layer. We study the nonlinear electromechanical response and the linear axisymmetric vibration of the system subject to different applied voltages and inner/outer pressures within the framework of the general nonlinear theory of electro-elasticity, the related linear incremental theory, and by considering the continuity conditions at the interface. We investigate instability behaviour using the same basic formulae. The state-space method provides efficient and accurate free vibration analysis, considering the dynamic response at the lowest frequencies, so we can neglect the viscous and damping effects, which is well suited to this problem. New results indicate that the bilayer system improves its frequency capability and stability compared to the monolayer dielectric tube. The thick outer elastic layer stiffens the bilayer system against axisymmetric bifurcation, bulging and necking instabilities. It also performs better in front of axisymmetric instability, increasing the system’s capability to receive or produce higher voltages, especially for long waves.This work thoroughly explains bilayer functional systems’ behaviour when exposed to extreme environments such as high voltage or pressure.

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Section: Introductionmentioning

confidence: 99%

Axisymmetric vibration and stability of dielectric-elastic tubular bilayer system

Almamo,

Su,

Chen

et al. 2024

Proc. R. Soc. A.

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“…To model electrode protection from aggressive agents, achieve greater actuation and improve the efficiency of energy harvesting, some researchers have proposed laminated or stacked SEA actuators and energy harvesters (Kovacs et al, 2009;Tutcuoglu and Majidi, 2014;Calabrese et al, 2018), which have been recently studied theoretically by Gei et al (2013), Cohen (2017), or Bortot (2019).…”

Section: Introductionmentioning

confidence: 99%

Nonlinear response and axisymmetric wave propagation in functionally graded soft electro-active tubes

Wu,

Destrade,

Chen

2020

Preprint

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Soft electro-active (SEA) materials can be designed and manufactured with gradients in their material properties, to modify and potentially improve their mechanical response in service. Here, we investigate the nonlinear response of, and axisymmetric wave propagation in a soft circular tube made of a functionally graded SEA material and subject to several biasing fields, including axial pre-stretch, internal/external pressure, and through-thickness electric voltage. We take the energy density function of the material to be of the Mooney-Rivlin ideal dielectric type, with material parameters changing linearly along the radial direction. We employ the general theory of nonlinear electro-elasticity to obtain explicitly the nonlinear response of the tube to the applied fields. To study wave propagation under inhomogeneous biasing fields, we formulate the incremental equations of motion within the state-space formalism. We adopt the approximate laminate technique to derive the analytical dispersion relations for the small-amplitude torsional and longitudinal waves superimposed on a finitely deformed state. Comprehensive numerical results then illustrate that the material gradients and biasing fields have significant influences on the static nonlinear response and on the axisymmetric wave propagation in the tube. This study lays the groundwork for designing SEA actuators with improved performance, for tailoring tunable SEA waveguides, and for characterizing non-destructively functionally graded tubular structures.

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“…Much effort has been devoted to the development of this theory in the last two decades (Ericksen, 2007;Suo et al, 2008;Liu, 2013;Dorfmann and Ogden, 2016), driven by recent applications in the real-world. So far, several finite deformations of dielectric structures have been investigated theoretically, including simple shear of a dielectric slab (Dorfmann and Ogden, 2005), inplane homogeneous deformation of a dielectric plate (Dorfmann and Ogden, 2014a), extension and inflation of a dielectric tube (Dorfmann and Ogden, 2006;Zhu et al, 2010) and a multilayer dielectric tube (Bortot, 2018), inflation of a dielectric sphere (Li et al, 2013;Dorfmann and Ogden, 2014b) and of a multilayer dielectric sphere (Bortot, 2017). Figure 1: Bending deformations in dielectric devices: (a) A strain sensor consisting of a stretchable dielectric sandwiched between two flexible ionic conductors attached to a straight finger: the bending of the finger stretches the sensor (Sun et al, 2014); (b) A 4-finger dielectric gripper: this actuator induces voltage-driven bending to lift a rock (Bar-Cohen, 2002); (c) Bending variations of the soft body and fins of a soft electronic "fish" made of dielectric elastomer and ionically conductive hydrogel: the fish can swim at a fast speed driven by periodical bending deformations (Li et al, 2017); (d) A dielectric actuator with a significant voltage-driven bending response (Bar-Cohen, 2002).…”

Section: Introductionmentioning

confidence: 99%

Finite bending and pattern evolution of the associated instability for a dielectric elastomer slab

Su¹,

Wu²,

Chen³

et al. 2019

International Journal of Solids and Structures

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We investigate the finite bending and the associated bending instability of an incompressible dielectric slab subject to a combination of applied voltage and axial compression, using nonlinear electro-elasticity theory and its incremental version. We first study the static finite bending deformation of the slab. We then derive the three-dimensional equations for the onset of small-amplitude wrinkles superimposed upon the finite bending. We use the surface impedance matrix method to build a robust numerical procedure for solving the resulting dispersion equations and determining the wrinkled shape of the slab at the onset of buckling. Our analysis is valid for dielectrics modeled by a general free energy function. We then present illustrative numerical calculations for ideal neo-Hookean dielectrics. In that case, we provide an explicit treatment of the boundary value problem of the finite bending and derive closed-form expressions for the stresses and electric field in the body. For the incremental deformations, we validate our analysis by recovering existing results in more specialized contexts. We show that the applied voltage has a destabilizing effect on the bending instability of the slab, while the effect of the axial load is more complex: when the voltage is applied, changing the axial loading will influence the true electric field in the body, and induce competitive effects between the circumferential instability due to the voltage and the axial instability due to the axial compression. We even find circumstances where both instabilities cohabit to create two-dimensional patterns on the inner face of the bent sector. H 1 J 2 J flexible electrodes O 3 J A L l

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Analysis of multilayer electro-active tubes under different constraints

Cited by 8 publications

References 46 publications

Axisymmetric vibration and stability of dielectric-elastic tubular bilayer system

Axisymmetric vibration and stability of dielectric-elastic tubular bilayer system

Nonlinear response and axisymmetric wave propagation in functionally graded soft electro-active tubes

Finite bending and pattern evolution of the associated instability for a dielectric elastomer slab

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