Tunable morphing of electroactive dielectric-elastomer balloons

Abstract

Designing smart devices with tunable shapes has important applications in industrial manufacture. In this paper, we investigate the nonlinear deformation and the morphological transitions between buckling, necking and snap-through instabilities of layered dielectric elastomer (DE) balloons in response to an applied radial voltage and an inner pressure. We propose a general mathematical theory of nonlinear electro-elasticity able to account for finite inhomogeneous strains provoked by the electro-mechanical coupling. We investigate the onsets of morphological transitions of the spherically symmetric balloons using the surface impedance matrix method. Moreover, we study the nonlinear evolution of the bifurcated branches through finite-element numerical simulations. Our analysis demonstrates the possibility to design tunable DE spheres, where the onset of buckling and necking can be controlled by geometrical and mechanical properties of the passive elastic layers. Relevant applications include soft robotics and mechanical actuators.

Axisymmetric vibration and stability of dielectric-elastic tubular bilayer system

“…We note that ηo=1 represents the case of the monolayer system. As the thickness of the elastic layer outside the dielectric tube increases, the bilayer system needs more axial compression to suffer from buckling instability, agreeing well with the result of [51]. For long tubes (αfalse^⪅1.9), the existence of the elastic layer has a negligible influence on the buckling behaviour of the bilayer system.…”

“…Motivated by the findings of Su et al . [51], which showed that the existence of the elastic layer outside the dielectric balloon can enhance the stability behaviour of the solid, we examine the stability of the bilayer system against buckling under a specific value of negative applied pressure and by reusing equation (3.48). We plot in figure 10 the critical axial stretch λz,cr as a function of the wavenumber αfalse^ with fixed ηi=0.85 and varying ηo=0.9,0.95,1, subject to Vfalse^=0.1 and normalΔPfalse^=−0.5.…”

Electromechanical Deformations and Bifurcations in Soft Dielectrics: A Review

“…For demonstrative purposes, specific forms of energy functions, including the neo-Hookean, Gent, and Ogden models, were utilized in numerical analyses for scenarios with either a fixed potential difference or a fixed charge distribution. Su et al [34] explored the nonlinear deformation in layered DE balloons, where an elastic layer is attached outside the DE balloon. They developed a comprehensive mathematical model that is capable of explaining the finite inhomogeneous strains caused by electro-mechanical interactions in the solid.…”

“…In recent years, with the widespread application of DEs capable of undergoing significant deformation, there has been a renewed interpretation and development of nonlinear electorelastic theory [17][18][19]. At this stage, this theory was extensively used in the study of various mechanical properties of the DE materials and structures, including nonlinear response [20][21][22], vibration [23][24][25][26][27], wave motion [28][29][30][31], instability [32][33][34], Photonics [35][36][37], etc.…”

Ultrasound generation in water via quasi-periodically snapping polymeric core–shell micro-bead excited with radiowaves

“…It is worth noticing that the succession of the Phases 1, 2 and 3, corresponds overall to a “snap-through-buckling” mechanism. Several groups have already investigated the (conditions of) occurrence of this mechanism in a broad plethora of structural elements theoretically and experimentally 17 – 19 .…”