电活性聚合物薄膜万能肌肉作动器的力电非线性变形分析

THE MECHANICAL-ELECTRO NONLINEAR DEFORMATION ANALYSIS OF UNIVERSAL MUSCLE ACTUATORS MADE OF ELECTRO-ACTIVE POLYMER MEMBRANE

该文针对美国人工肌肉公司(Artificial Muscle Inc.)开发的一款电活性聚合物薄膜作动器,建立了该产品核心部件即上下表面附着有柔顺电极的圆环形电活性聚合物薄膜在力电作用下产生面外轴对称大变形的力学模型,利用热力学的基本理论,推导得到了圆环形薄膜在受力电载荷作用时产生面外大变形的控制方程,采用打靶法对控制方程进行了数值求解,结果表明:圆环形薄膜的变形是非常不均匀的,在靠近圆环中心处的薄膜变形较大,而靠近圆环边缘处的薄膜变形较小,导致薄膜中的电场从外向内逐渐变大。变形场的非均匀性导致薄膜内的大部分材料并没有被有效地利用,造成了材料的浪费。该文的研究结果对该商业化产品的优化设计具有实际的指导意义。

This paper focuses on investigating the axisymmetric out-of plane nonlinear deformation of an actuator made of electro-active polymer membrane and designed by American Artificial Muscle Inc.. The essential part of the actuator is a layer of annular electro-active polymer membrane sandwiched between two compliant electrodes. The mechanical model describing the axisyrnmetric nonlinear deformation of such annular membrane is formulated, and the equilibrium equations characterizing the large deformation of the annular membrane subject to a concentrated force and a voltage are derived by thermodynamics. The derived state equations are solved by using shooting method. The obtained numerical results show that the deformation field in the membrane is highly inhomogeneous. The deformation near the central part of the membrane is large while the deformation near the edge of the membrane is small, which leads to the induced electric field in the membrane where the deformation increases monotonically from the edge to the central part and reaches the maximum at the central part of the membrane. Due to the irthomogeneity of deformation field, the membrane material is not utilized efficiently, which results in material waste.