Reliability evaluation of dielectric elastomer balloon subjected to harmonic voltage and random pressure

Abstract

Subjected to electric and/or mechanical stimuli, either deterministically or stochastically, dielectric elastomer structures may undergo remarkable oscillations which can deteriorate the operating performance or even induce complete failure. This work investigates the reliability evaluation of ideal dielectric elastomer balloon subjected to harmonic voltage and random pressure simultaneously, with the objective to provide some guidance on the design of dielectric elastomer structures/ components. The operating safety domain is determined by the material strength of dielectric elastomer material, while the reliability evaluation comes down to solving a first-passage failure problem in mathematics. The stochastic differential equations with respect to the first integral and phase difference are derived by executing a special transformation and stochastic averaging. The reliability function (i.e., the probability of system states being in a specified safety domain in a given time interval) is then obtained by numerically solving the associated backward Kolmogorov equation. The influences of some crucial parameters (e.g., the initial energy, the intensity of random pressure, the amplitude and frequency of harmonic voltage) on the reliability are discussed in detail.