Model-Based Investigation of Distributed Sensing in Dielectric Elastomer Membranes

When a dielectric elastomer (DE) membrane is used as a deformation sensor, changes in its electrical capacitance can be exploited to reconstruct the transducer average strain. At sufficiently high frequencies, however, a DE behaves more like an RC transmission line than just a capacitor. By detecting changes in the frequency response of the resulting DE transmission line, one can implement advanced sensing paradigms in which single-port measurements of the impedance allow estimating a distributed deformation pattern along the membrane. In this work, we present a parametric study aimed at evaluating how material properties, geometry, and deformation patterns influence a DE membrane’s impedance frequency response, which in turns provides a measure of the membrane’s ability to work as a distributed sensor. The analysis relies on a previously validated physicsbased continuum model, used to estimate the impedance frequency response at the input port of a deformed DE membrane. Parametric studies show that the ability of the system to resolve deformation patterns (i.e., generating different impedance profiles) strongly depends on some specific parameters, such as the dependence of the electrode sheet resistance on the stretch. The results provide useful insights on the material requirements for the dielectric and electrode materials, and the limits in terms of measurable deformation profiles.