圆形电场活化聚合物致动器中的褶皱和吸合不稳定性

Wrinkling and pull-in instabilities of circular dielectric elastomer actuators

电场活化聚合物(Dielectric Elastomer,DE)具有优异的力学性能,在电场作用下应变可达100%以上.作为一种新型的致动器,它被广泛地应用于医疗设备、适应性光学仪器和机器人等领域.根据Tommasi等人研究DE薄膜稳定性的方法,本文着力分析了圆形电场活化聚合物致动器中的褶皱和吸合不稳定性,旨在方便、直接地指导致动器设计.基于简单的几何和材料假定,作者考虑了预拉伸、致动区尺寸和材料模型这些影响DE技术应用的重要因素,采用一种解析方法有效地描述了褶皱和吸合失稳,并对失稳机理做出了清晰的物理解释.作为结果,本文给出了不同预拉伸值时失稳的一系列临界参数,找到了满足不同需求的最优预拉伸值,并与实验比较吻合较好.

When subject to an electric field, a dielectric elastomer （DE） deforms, possibly straining over 100%. Due to their distinctive mechanical properties, the DEs are being developed as actuators for broad applications, such as armaria, adaptive optics, and robots. According to a method to study instabilities of DE films proposed by Tommasi et al, this paper focuses on analyzing wrinkling and pull-in instabilities of circular dielectric elastomer actuators in order to guide the design of actuators conveniently and directly. Based on simple geometrical and material assumptions, the authors consider the effects of pre-stretch, the size of activated region and material model, which are all crucial in technological applications of DEs. A valid analytical method is used to describe the occurrence of wrinkling and pull-in, which gives clear physical interpretations of these failure mechanisms. As a result, this paper gives a series of critical parameters corresponding to instabilities in different pre-stretch values and the optimal pre-stretch values for some needs. They agree with the experiments well.