介电弹性体驱动器在单轴预拉伸条件下的机电稳定性分析

On Electromechanical Stability Analysis for the DE Actuator with Uniaxial Pre -stretch

介电弹性体在外加电场作用下具有超大的可逆变形能力，其质量轻、驱动电压低、响应快、输出力大，与外界环境适应性好，这些特点使其成为新型智能驱动器的佼佼者。在外加电场的激励下，介电弹性体驱动器的厚度会减小，从而引起电场强度增大，增大的电场强度进一步加剧驱动器厚度的减小，这一反馈过程会导致驱动器发生电击穿。本文采用Neo—Hookean应变能函数，根据稳定状态下系统自由能对应的海森矩阵正定的特性，建立了介电弹性体驱动器在单轴预拉伸条件下的机电稳定性条件，并采用有限元方法计算了单轴预拉伸条件下驱动器的机电响应，仿真计算结果和理论分析结果完全吻合，得到的稳定性条件和有限元建模方法可以为驱动器的设计提供参考。

Dielectric elastomer has large reversible deformation ability under the action of external electric field, its light weight, low driving voltage, fast response, large output force, and adaptability to the environment, these features make it the best model of intelligent actuator. When an external electric field is applied, dielectric elastomer actuator thickness will decrease, thus cause increasing of electric field strength, the stronger electric field strength furtherly decreases actuator thickness, this feedback process leads to actuator electrical breakdown. Based on Neo -Hookean strain energy function, according to the theory that at the equilibrium state, the Hessian Matrix of the system free energy must be positive definite, the equilibrium equations which describe the relationships between input and output are derived. The behaviour of the actuator with uniaxial pre - stretch and voltage is simulated by ABAQUS as well. The simulation results agree well with the analytic results. And the equilibrium equations obtained and the method used in the FEM can be used in the design of DE actuators.