Document Type

Conference Paper

Publication Date

9-2-2026

Abstract

Dielectric elastomers are soft electro-active materials that deform under applied electric fields, making them compelling candidates for next-generation sensing, actuation, and energy-generation technologies. Simulation-based design and real-time control of such devices require constitutive models with genuine predictive capability, which is difficult given the highly nonlinear, tightly coupled electro-mechanical response of dielectric elastomers. A persistent open question in the community is whether the permittivity of neat, unfilled dielectric elastomers is stretch-dependent. Existing measurements are largely confined to biaxial loading, and the comparatively few studies under uniaxial tension are limited to modest stretches (λ ≤ 6), a constraint likely arising from edge effects and mixed stress states inherent to the rectangular specimen geometries employed. This is despite recent experiments and micromechanical arguments (e.g., chain alignment and dipole reorientation along the loading direction) suggesting that a dielectric elastomer’s permittivity–stretch response depends on the state of stretch, not just stretch magnitude alone. Thus, the overarching goal of this research is to experimentally quantify the stretch-dependence of permittivity in VHB 4910 under uniaxial tension using an upscaled ASTM D412 dogbone specimen, designed to ensure a genuinely uniaxial stress state at extreme stretches, together with a compliant, co-deforming carbon grease electrode representative of practical soft actuator configurations. Through-thickness relative permittivity was determined from measured capacitance and electrode area at 1 kHz up to an extreme axial stretch of λ = 8.72, well beyond previously reported uniaxial stretch ranges. The relative permittivity decreases modestly and monotonically from 4.90 at λ = 1 to 4.29 at λ = 8.72 (a 12% reduction), consistent with stretch-induced dielectric anisotropy. Given that the degree of stretch-induced anisotropy is expected to depend on loading state, it is therefore recommended that permittivity–stretch curves acquired in different deformation modes (e.g., equi-biaxial tension and uniaxial tension) not be directly compared, and that loading state should be regarded as a reported test condition on equal footing with measurement frequency.

Keywords

Elastomer, Soft Robotics, Dielectric Elastomer Actuator, Electromechanical, Artificial Muscles

Disciplines

Applied Mechanics | Electro-Mechanical Systems

Comments

Thanks to the University of Dayton Honors Program and the Berry Summer Thesis Institute for enabling this research experience over the summer with their work, funding, and support. Also, thanks to the Berry family for their financial contribution and their efforts to offer great research experiences, and professional and academic development, to the next generation. Special thanks to the Behavior of Advanced Materials and Structures Laboratory members, my graduate mentor Samuel Conley, my mentor at Oakland University, Dr. Christopher Cooley, my faculty mentor Dr. Robert Lowe, and our AFRL collaborator Dr. Matt Grasinger for their support, guidance, and help this summer. 

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