Manipulating torsional motions of soft dielectric tubes

Abstract

Tubular dielectric elastomers function as actuators by application of a radial voltage difference. This work demonstrates how the applied electric field can be exploited to manipulate their torsional motion. The approach employed considers torsional elastic waves superposed on a finitely deformed configuration, which depends on bias electromechanical loadings. The theory of nonlinear electroelasticity is utilized to derive the corresponding governing equations. These are analyzed analytically and numerically, as functions of the thickness of the tube, the mechanical constraints, and most importantly the applied voltage. The analysis shows how dispersive waves beyond a certain length are filtered across a frequency band, and are significantly accelerated above it. This phenomenon observed to strongly depend on the applied voltage, in a non-linear manner.

On propagation of axisymmetric waves in pressurized functionally graded elastomeric hollow cylinders

“…Therefore, the interested reader can be referred to Wu et al [4] for more details. In addition to the circumferential waves, much effort has been also devoted to the investigation of guided elastic waves propagating along the longitudinal (or axial) direction in (soft) hollow cylinders [14][15][16][17][18][19][20][21][22][23][24][25][27][28][29][30], which is also very important to ultrasonic non-destructive evaluation, signal processing in electronic devices, phononic crystals and metamaterials, etc. [1,3].…”

“…Interestingly, the inhomogeneous deformations and stresses generated by the combination of the pressure difference and axial pre-stretch have been used to realize hyperelastic cloaking and tunable elastodynamic band gaps of anti-plane elastic waves [11,12]. More recently, Shmuel and deBotton [29], Shmuel [30], and Wu et al [4] considered respectively the axisymmetric, torsional, and circumferential waves propagating in soft electroactive tubes subjected to a radially applied electric field as well as an axial mechanical force. The application of an electric voltage difference to the inner and outer surfaces of the soft electroactive tube will also result in radially inhomogeneous deformation fields, similar to the case of a radial pressure difference.…”

Nonlinear electroelasticity: material properties, continuum theory and applications

“…Several papers dealing with small-amplitude waves and motions superposed on finite deformations in the presence of an electric field have been investigated by Shmuel & deBotton [146,147], Shmuel et al [148], Shmuel [149,150], Su et al [151] and Wu et al [152] based on the general quasi-electrostatic approximation theory in Dorfmann & Ogden [49], wherein the theory was applied to electroelastic surface waves propagating on a half-space.…”

Tuning sound with soft dielectrics

“…The response of a soft dielectric tube subjected to a radial electric field has been reported in several instances (Singh 1966, Zhu et al 2010, Zhou et al 2014a, Shmuel 2015; herein, we apply the derivation in Shmuel and deBotton (2013) to a tube made of an elastomer exhibiting strain-stiffening at large deformations.…”